No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Immobilization stress-induced antioxidant defense changes in rat plasma: Effect of treatment with reduced glutathione
Abstract
1.1. We examined immobilization stress-induced antioxidant defense changes in rat plasma and observed the antioxidant effect of reduced glutathione (GSH) administration on these changes.2.2. Immobilization stress induced severe bleeding in the stomach and a significant increase in plasma levels of thiobarbituric acid receives substances (TBARS).3.3. Immobilization stress induced a significant decrease in plasma iron-binding, ironoxidizing protections and radical scavenging activity.4.4. Plasma levels of ascorbic acid, ascorbyl radical and superoxide dismutase activity remained unchanged following immobilization stress.5.5. Treatment with GSH showed a significant protective effect on stomach bleeding, on the increase in plasma TEARS, and on the decrease of iron-binding, iron-oxidizing protection and radical scavenging activity in plasma.6.6. These results suggest that immobilization stress induces generation of reactive oxygen species and decreases the endogenous antioxidant defenses, which can be attenuated by extracellular administration of antioxidant GSH.
... Moreover, several preclinical and clinical studies have shown that mitochondrial dysfunction in the brain is linked to affective mood disorders such as anxiety and depression (Allen et al., 2018;Hollis et al., 2015). Previous studies have proven that prolonged stress exposure impairs mitochondrial function and the antioxidant defense system which in turn leads to oxidative damage through shifting the balance between oxidant and antioxidant factors (Liu et al., 1994;Maes et al., 2011). A number of studies have also demonstrated increased ROS levels in major depression (Smaga et al., 2015;Maes et al., 2011) and antidepressants with antioxidant properties have been shown to improve clinical symptoms of depression (Lee et al., 2013). ...
... Under physiological conditions, endogenous antioxidant system, including enzymatic and non-enzymatic antioxidants, neutralizes free radicals (Salim, 2017). Nevertheless, stress exposure impairs the detoxification capacity of the antioxidant defense system through shifting the balance between oxidant and antioxidant factors and ultimately resulting in oxidative stress (Liu et al., 1994;Maes et al., 2011). Moreover, it has been established that oxidative stress and excessive production of ROS and reactive nitrogen species are primary factors in the pathogenesis of depression and anxiety (Smaga et al., 2015;Zafir and Banu, 2009;de Souza Balk et al., 2010;Maria Michel et al., 2012;Maes et al., 2011) and many agents with antioxidant properties improve symptoms of depression (Lee et al., 2013). ...
... Among the organs in the human body, the CNS takes more than its share of oxidative abuse [1,12,13]. The main factors that contribute 2 Evidence-Based Complementary and Alternative Medicine to the vulnerability of brain to oxidative damage include high content of polyunsaturated fatty acids in the membranes and low levels of enzymatic and nonenzymatic antioxidants [14]. One of the most important consequences of the generation of free radical is the peroxidation of membrane lipids. ...
... Although acetylcholine induces contraction of skeletal muscle, it acts via a different type of receptor (muscarinic) to inhibit contraction of cardiac muscle fibres [14]. Oxidative stress is discussed as a contributor to the initiation or progression of cellular damage and has been implicated in the pathophsiology of many neurodegenerative diseases by inducing the reactive oxygen species (ROS) that oxidize vital cellular components such as lipids, proteins and DNA which produces potentially harmful effects [15]. The cerebellum plays an important role in motor control, and it is involved in some cognitive functions such as attention and language, and probably in some emotional functions such as regulating fear and pleasure responses [16]. ...
Xanax is an agent with hypnogenic, anxiolytic, anticonvulsant, and muscle relaxant properties and has generally been used as a hypnotic/tranquilizer. The aim of this paper was to investigate the effect of Xanax on acetylcholinesterase and glutathionestransferase enzyme activities on the cerebellar tissues of male mice. Sixty male mice were randomly assigned into four groups (15 mice/each) according to their approximately equal mean body weight. Mice that received orally by gavage 0.5 ml saline solution of 0.9% NaCl were considered as a control mice. Other experimental mice were daily administered orally by gavage with 0.5 ml of different three doses of Xanax (0.5, 1 and 1.5 mg/kg bw), for two months. Biochemical analyses revealed significant decreases in the activities of acetylcholinesterase and glutathionestransferase enzyme in the brain tissues of mice administered with the three doses of Xanax. The major mechanism involved appears to be the result of oxidative stress scavenging action on the neuronal cells of cerebellar cortex of male mice.
... Based on above facts, we hypothesized that CG plus can be a potential candidate modulating stress-derived hepatotoxicity. We herein adopted a mouse model of immobilization which has been adapted as a physical and psychological severe stress (Liu et al., 1994). And then we investigated the hepatoprotective effects of CG plus and its underlying corresponding mechanisms on stress-related hepatic damage. ...
Introduction
Stress is a well-known factor for inflammation in diverse organs/tissues. Stress also leads to liver injury, which was supported by clinical observations and animal studies. We herein investigated the hepatoprotective property of an herbal formula (called as CGplus) consisting of Artemisia gmelinii Weber ex Stechm. (syn, Artemisia iwayomogi Kitamura), Wurfbainia villosa var. xanthioides (Wall. ex Baker) Skornick. & A.D.Poulsen (syn, Amomum xanthioides Wallich), and Salvia miltiorrhiza Bunge against stress-induced hepatic damage.
Methods
Male BALB/c mice were orally administered water extract of CGplus (0, 50, 100, or 200 mg/kg) daily for 5 days, and then subjected to immobilization stress for 6 h on the 5th day.
Results
Acute immobilization stress elevated remarkably serum concentrations of stress hormones (corticosterone and adrenaline) and two hepatic injury parameters (ALT and AST), while these alterations were significantly attenuated by the administration of CGplus. The increases of oxidative parameters (ROS, NO, lipid peroxidation, and protein carbonyl) and deviation of IL-1β and IL-10 in opposite directions in hepatic tissues were significantly normalized by CGplus. Pre-treatment with CGplus also notably ameliorated the abnormal activation of toll-like receptor 4 (TLR4), CD14, and lipopolysaccharide-binding protein (LPB) as well as infiltration of neutrophils in hepatic tissues.
Conclusion
These results suggest that an herbal formula (CGplus) derived from traditional pharmaceutical theory has a potent protective effect against stress-induced hepatic injury via regulation of pro- (IL-1β) and anti-inflammatory (IL-10) cytokines.
... To correlate changes in a marker of oxidative stress, neurotransmitter levels, and PD symptoms, malondialdehyde (MDA), dopamine (DA), and serotonin levels were evaluated in brain tissues. Our results showed that MDA levels were increased in the striatum, the prefrontal cortex, and the hippocampus of maternally separated (MS) rats in agreement with studies by Mabandla and Russell [29], who showed that 6-OHDA is an oxidative stress-induced neurodegeneration [77][78][79][80][81][82]. As our stereotaxic injection of 6-OHDA into the MFB (to disrupt striatal, prefrontal cortex, and hippocampal innervation) also provided a good measurement of oxidative damage in the brain, it was evident that the lesion contributed to the observed decreased use of the right forelimb (impaired) of MS rats in the cylinder test. ...
Nonmotor symptoms (NMS) such as anxiety, depression, and cognitive deficits are frequently observed in Parkinson’s disease (PD) and precede the onset of motor symptoms by years. We have recently explored the short-term effects of Fluvoxamine, a selective serotonin reuptake inhibitor (SSRI) on dopaminergic neurons in a parkinsonian rat model. Here, we report the long-term effects of Fluvoxamine, on early-life stress-induced changes in the brain and behavior. We specifically evaluated the effects of Fluvoxamine on brain mechanisms that contribute to NMS associated with PD in a unilateral 6-hydroxydopamine-lesioned rat model. A 14-day early postnatal maternal separation protocol was applied to model early-life stress followed by unilateral intracerebral infusion of 6-hydroxydopamine (6-OHDA) to model aspects of parkinsonism in rats. The anxiolytic, antidepressant, and cognitive effects of Fluvoxamine were confirmed using the elevated plus-maze (EPM) test, sucrose preference test (SPT), and Morris water maze (MWM) test. Further to that, our results showed that animals exposed to early-life stress displayed increased plasma corticosterone and malondialdehyde (MDA) levels which were attenuated by Fluvoxamine treatment. A 6-OHDA lesion effect was evidenced by impairment in the limb-use asymmetry test as well as decreased dopamine (DA) and serotonin levels in the striatum, prefrontal cortex, and hippocampus. These effects were surprisingly attenuated by Fluvoxamine treatment in all treated rats. This study is the first to suggest that early and long-term treatment of neuropsychological diseases with Fluvoxamine may decrease the vulnerability of dopaminergic neurons that degenerate in the course of PD.
... This effect could bedue to sedative action as well as ataxic action of alprazolam and Ocimum sanctum and might be acting through the serotonergic system or it could be due to the change in the humoral response as reported by Mediratta et al have reported that Ocimum sanctum modulates the humoral response by acting at various levels in the immune mechanism such as antibody production, release of mediators of hypersensitivity reactions and tissue response to thesemediators. 10,11 Although mechanism of action of anti-stress activity of alprazolam is well known but the exact mechanism of action of Ocimum sanctum is yet to be ascertained. Ocimum sanctum plant contains alkaloids, glycosides, tannins and saponins. ...
Background: Stress is the physiological, psychological and behavioral response by individuals when they perceive a lack of equilibrium between the demands placed upon them and their ability to meet those demands, which over a period of time leads to ill health. There are several ways of coping with stress. Some techniques of time management may help a person to control stress.Methods: Forced swim test- mice were randomized into two groups according to the body weights. Each group contains six animals. Each individual animal was allowed to swim inside the jar (25-12-25 cm) containing fresh water up to 15 cm height. Mice were allowed swim for 6 min. After initial struggle to escape the animal became immobile. Total immobility period was measured. Rotarod test- mice were randomized into two groups according to body weights. Each group contains six animals. Rats were placed on the lanes. Latency period was recorded at which each rat falls off the rod.Results: In first experiment, anti-stress activity of Ocimum sanctum in mice was demonstrated by measuring the immobility period during forced swim test and in the second experiment the measurement of the latency period of rats in rotarod apparatus was performed. Both the experimental procedures were compared with standard anti stress drug alprazolam.Conclusions: The present study suggests that Ocimum sanctum possess significant anti stress activity but less when compared to alprazolam.
... This effect could bedue to sedative action as well as ataxic action of alprazolam and Ocimum sanctum and might be acting through the serotonergic system or it could be due to the change in the humoral response as reported by Mediratta et al have reported that Ocimum sanctum modulates the humoral response by acting at various levels in the immune mechanism such as antibody production, release of mediators of hypersensitivity reactions and tissue response to thesemediators. 10,11 Although mechanism of action of anti-stress activity of alprazolam is well known but the exact mechanism of action of Ocimum sanctum is yet to be ascertained. Ocimum sanctum plant contains alkaloids, glycosides, tannins and saponins. ...
... Thus, GSH levels may be found to be increased in the recovery period after stress. There have been many reports of stress-induced lipid peroxidation in plasma (Liu et al. 1994) and in different tissues (Oishi et al. 1999;Gumuslu et al. 2002;Seckin et al. 1997) of animals. These results agree with the result of this study. ...
The aim of this study was to investigate the effects of acute, repeated and chronic restraint stress on the antioxidant status and lipid peroxidation. For this purpose, 48 male Wistar rats, aged three months were used in this study. Rats were separated into six groups as follows; control (C), acute stress (AS), restrained for 7 days (1 h/day) (RS), restrained for 21 days (1 h/day) (CS1), restrained for 28 days (1 h/day) (CS2) and restrained for 21 days (1 h/day) and allowed to recovery for 7 days (CS3). Copper, zinc-superoxide dismutase (Cu, Zn-SOD), catalase (CAT) and selenium-dependent glutathione peroxidase (Se-GSH-Px) activities, corticosterone, reduced glutathione (GSH) and thiobarbituric acid-reactive substances (TBARS) levels were measured in blood samples. Corticosterone levels of all groups were found to be elevated after stress compared to group C. Cu, Zn-SOD activity was lower in all stress groups than in group C. CAT and Se-GSH-Px activities were increased in all stress groups. All stress models decreased GSH levels except for the CS3 group. TBARS levels were higher in stress groups than in C group except for AS group. The highest corticosterone level, CAT and Se-GSH-Px activity and TBARS level were seen in group RS. The lowest Cu, Zn-SOD activity and GSH level were seen in group CS2. These results may have an important implication for impaired erythrocyte antioxidant enzyme activities and glutathione levels resulting from exposure to different stress models (acute, repeated and chronic restraint stress).
... [8] Restraint stress has also been reported to bring out the antioxidant defense changes in rat liver. [36] SOD, CAT, and GST play a vital role in scavenging oxy-radicals and their products. [22,37] The stability of living organism must be maintained by its balance between oxidative and antioxidant defense. ...
Introduction
This study was carried out to evaluate the antioxidant potential of crude extract of Solanum nigrum leaves and its active constituents as treatment against restraint stress in rat’s liver.
Methods
For this purpose, male albino Wistar rats were treated with crude extract of leaves and its alkaloid and flavonoid fractions both before and after 6 h of acute restraint stress. Prooxidant status of rat liver was assessed by determining the levels of thiobarbituric acid reactive substances, reduced glutathione, alkaline phosphatase, alanine transaminase, aspartate aminotransferase, and the activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST).
Results
Six hours of restraint stress generated oxidative stress in rat’s liver resulted in a significant rise in the level of the aforementioned liver enzymes. On the other hand, SOD, CAT, and GST enzymatic activities showed a significant decline in their level. The administration of crude leaves extract, both before and after stress exposure, significantly prevented the rise in the level of liver enzymes and reverted the activities of studied biochemical parameters toward their normal control values. However, the reversion was found to be more prominent in after-stress group.
Conclusion
The aforementioned results highlight the significant antioxidant potential of S. nigrum extracts. On the basis of our study, we suggest the possible use of S. nigrum leaves extract as a nutritional supplement for combating oxidative stress induced damage.
... The mechanism of induction of stress-related damage to the CNS is still under debate, but it is believed that there is an imbalance between the antioxidant defenses and the generation of reactive species and/or free radicals causing oxidative damage. Under pathological conditions, the brain is the main organ undergoing oxidative damage, as it has low levels of antioxidants and a high content of polyunsaturated fatty acids in its membranes, becoming more vulnerable to the attack of reactive oxygen species (ROS) (Halliwell and Gutteridge 1985;Floyd 1991;Liu et al. 1994Liu et al. , 1996Zaidi and Banu 2004). To this regard, it is known that the daily intake of antioxidants that cross the blood-brain barrier (BBB) and reach the CNS is fundamental to afford protection against the possible stress affecting the body homeostasis (Zaidi and Banu 2004;Colín-González et al. 2015;Becerril-Chávez et al. 2017). ...
Positive influence of yerba mate (Ilex paraguariensis) on human health issues has been attributed to its frequent consumption in South American countries and is assumed to be due to its high content of antioxidant compounds, including chlorogenic acid (CGA); however, hard evidence about its positive effects under chronic stress conditions is still required. In this study, the effects of yerba mate extracts (IpE), and its main compound chlorogenic acid (CGA), on behavioral and morphological endpoints of brain damage induced by chronic restraint stress (CRS) to rats were evaluated and compared. CRS sessions were performed during 21 days. IpE (200 mg/mL, p.o.) or CGA (2 mg/mL, p.o.) were administered daily 30 min before stress. Behavioral tests comprised motor skills and anxiety-like activity. Histological (H&E) and histochemical changes were explored in three brain regions: cortex (Cx), hippocampus (Hp), and striatum (S). Rats subjected to CRS exhibited hypoactive patterns of locomotor activity. Rats receiving IpE before CRS preserved the basal locomotor activity. Stressed animals also augmented the anxiety-like activity, whereas IpE normalized exploratory behavior. Stressed animals presented cell damage in all regions. Morphological damage was more effectively prevented by IpE than CGA. Stressed animals also augmented the expression/localization pattern of the tumor necrosis factor alpha in the striatum and the expression of the glial fibrillary acidic protein in the hippocampus (stratum moleculare) and cortex, whereas IpE and CGA reduced the expression of these molecules. In turn, CGA exhibited only moderate protective effects on all markers analyzed. Our findings support a protective role of IpE against CRS, which may be related to the antioxidant and anti-inflammatory properties of its compounds. Since CGA was unable to prevent all the alterations induced by CRS, it is concluded that the protective properties of the whole extract of Ilex paraguariensis are the result of the combined effects of all its natural antioxidant compounds, and not only of the properties of CGA.
... Stress has been well documented to enhance the production of free radicals (Liu et al., 1994). Increase free radicals has been linked to hyper-activation of the hypothalamic-pituitary-adrenal axis with resultant increase in corticosterone secretion (Liu et al., 1996). ...
Introduction
As stress affects the brain both physiologically and chemically, researchers try to find novel anti-stress compounds with beneficial therapeutic effects. In this regard, the effect of stress and its modulation by Morin hydrate was studied using different acute models in mice.
Methods
The models employed were anoxic tolerance, swimming endurance, and acute restraint test. Morin hydrate or the vehicle was administered 30 minutes prior to each stress exposure while in the acute restraint test; the animals were pretreated for 7 days with Morin hydrate, vehicle, imipramine, or diazepam before stress exposure. The measured parameters were the onset of convulsion and immobility time in the anoxic tolerance and swimming endurance test, respectively, while in the acute restraint test, the animals were assessed for stress-induced anxiety using the elevated plus maze and depression using the forced swim test. Thereafter blood was withdrawn from the retro-orbital plexus and plasma separated, the brain was also isolated, homogenized, centrifuged, and the supernatant was obtained for biochemical estimation.
Results
Morin hydrate (5, 10, 20 mg/kg) produced a significant reduction in immobility time in the swimming endurance test, while significantly increased the anoxic stress tolerance time. Acute restraint stress caused a significant decrease in reduced glutathione levels (which was reversed by Morin hydrate) and increased the level of malondialdehyde, a thiobarbituric acid reactive substance which is an index of oxidative stress and nitrite. These effects were attenuated by Morin hydrate. Also, pretreatment with Morin hydrate attenuates acute restraint stress-associated anxiety and depression, reversed the hyperglycemia evoked by the stressful exposure and normalized serum cholesterol levels.
Conclusion
These findings suggest that Morin hydrate exhibits anti-stress effects and may be useful in the relief of stress.
... Diabetes-associated hyperglycemia causes excessive production of ROS, which directly induces vascular endothelial dysfunction and indirectly reacts with intracellular NO to form peroxynitrite, a cytotoxic substance associated with diabetic cardiovascular diseases, including endothelial dysfunction and heart failure (42,43). Immobilization stress has been shown to cause ROS formation and change antioxidant defenses in rat plasma (33). Inflammatory responses due to excess ROS formation are also important in the development of cardiac abnormalities (13). ...
Although stress is one of the risk factors of diabetes, few studies have assessed the effects of stress on diabetic rats. This study therefore analyzed differences in cardiovascular-related factors among control, non-stressed diabetic, and stressed diabetic rats, as well as assessed the effects of linalyl acetate (LA) on stressed diabetic rats. Male Sprague-Dawley rats were subjected to immobilization stress throughout the entire experimental period, and diabetes was induced on day 15 by a single injection of streptozotocin. After confirming the induction of diabetes, stressed diabetic rats were administered LA (10 mg/kg or 100 mg/kg) or metformin (500 mg/kg) for the last 7 days. Compared with non-stressed diabetic rats, stressed diabetic rats had significantly lower body weight, body fat percentage, ACh-induced vasorelaxation, systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and NF-κB expression, as well as increased serum nitrite concentration. Although metformin increased serum insulin concentration significantly, LA 100 mg/kg showed only an increasing tendency. However, treatment with LA 100 mg/kg not only reduced serum glucose and NF-κB expression, but restored ACh-induced vasorelaxation, SBP, DBP, HR, AMP-activated protein kinase (AMPK) expression and serum nitrite almost to control levels. Importantly, LA 100 mg/kg was more effective than metformin in ameliorating serum glucose, eNOS expression, HR, and serum nitrite. These findings suggest that chronic stress can aggravate endothelial dysfunction and hemodynamic alterations in diabetes and that LA may have potent therapeutic efficacy in diabetic patients with cardiovascular disease complications or chronic stress.
... In the present study, CS and CUS brought about noteworthy rise of MDA (a marker of lipid peroxidation) and decrease in the levels of GSH (an endogenous anti-oxidant). According to previous reports, free radicals have been produced by stress [33], which further increase corticosterone secretion through hyper-actuation of the HPA axis [34]. On the other hand, HPA over-stimulation brought about by free radicals elevates corticosterone secretion by disrupting hippocampal neurons, which sustain the homeostasis of the HPA axis by negative feedback system [35]. ...
Background:
Oxitard, a polyherbal formulation comprising the extracts of Withania somnifera, Mangifera indica, Glycyrrhiza glabra, Daucus carota, Vitis vinifera, powders of Syzygium aromaticum, Yashada bhasma and Emblica officinalis; and oils of Triticum sativum.
Objective:
Current study deals with the assessment of Oxitard (a marketed polyherbal formulation) for its adaptogenic potential in chronic unpredictable stress (CUS) and chronic stress (CS) induced dysfunctional homeostasis in rodents.
Materials & methods:
Animals were immobilized for 2 h every day for ten days to induce CS. In order to induce CUS, animals were employed in a battery of stressors of variable value and duration for ten days. Following administration of Oxitard, stress was induced in the animals. Stress-induced efficient changes were evaluated by assessing organ (adrenal gland) weights, ulcer index, hematological parameters and biochemical levels of reduced glutathione (GSH), thiobarbituric acid reactive substances (TBARS) and catalase (CAT).
Results:
CS and CUS significantly modified the oxidative stress parameters (increased MDA and decreased GSH). Furthermore, CS and CUS lead to weight reduction, adrenal hypertrophy and gastric ulceration. Pre-treatment with Oxitard (200 and 400 mg/kg, p.o.) significantly modified CS and CUS induced hematological changes, oxidative stress parameters and pathological effects.
Conclusion:
In conclusion, Oxitard-intervened antioxidant actions are accountable for its adaptogenic effects in stress-induced dysfunctional homeostasis.
... Studies have shown that exposure to stress induces lipid peroxidation in the brain (Liu et al., 1994;Matsumoto et al., 1999;Madrigal et al., 2001). The positive correlation between plasma corticosterone concentration and lipid peroxidation suggests that elevated corticosterone concentration plays a role in increasing lipid peroxidation (Sahin and Gumuslu, 2004). ...
... In our study, GSH, the most abundant antioxidant thiol present in mammalian cells, was decreased in rats exposed to PUS, neonatal poly (I:C) and poly(I:C) + PUS. Previous experiments have shown that immobilization stress in rodents induces generation of reactive oxygen species and decreases endogenous antioxidant defenses, which can be attenuated by extracellular administration of antioxidant GSH [45]. Decreased brain levels of GSH is also a core brain alteration observed in animal models of schizophrenia [8,46] and in schizophrenia postmortem patients [39]. ...
Schizophrenia is considered to be a developmental disorder with distinctive sex differences. Aiming to simulate the vulnerability of the third trimester of human pregnancy to the developmental course of schizophrenia, an animal model was developed, using neonatal poly(I:C) as a first-hit, and peripubertal stress as a second-hit, i.e. a two-hit model. Since, to date, there have been no references to sex differences in the two-hit model, our study sought to determine sex influences on the development of behavior and brain oxidative change in adult rats submitted to neonatal exposure to poly(I:C) on postnatal days 5-7 as well as peripubertal unpredictable stress (PUS). Our results showed that adult two-hit rats present sex-specific behavioral alterations, with females showing more pronounced deficits in prepulse inhibition of the startle reflex and hyperlocomotion, while males showing more deficits in social interaction. Male and female animals exhibited similar working memory deficits. The levels of the endogenous antioxidant, reduced glutathione, were decreased in the prefrontal cortex (PFC) of both male and female animals exposed to both poly(I:C) and poly(I:C)+PUS. Only females presented decrements in GSH levels in the striatum. Nitrite levels were increased in the PFC of male and in the striatum of female poly(I:C)+PUS rats. Increased lipid peroxidation was observed in the PFC of females and in the striatum of males and females exposed to poly(I:C) and poly(I:C)+PUS. Thus, the present study presents evidence for sex differences in behavior and oxidative brain change induced by a two-hit model of schizophrenia.
... Stress also induces redox imbalance associated with reactive oxygen spices (ROS) production via numerous cellular cascades [11][12][13]. Gostner et al. [14] reviewed the key functions that ROS and other redox-active molecules fulfill in immunity. Stress is now considered as an important modulator of the immune system [15][16][17] and a major cause of increased risk for immune-related diseases, such as inflammatory diseases, infection, and cancer [18][19][20]. ...
We investigated if the orally administered Lactobacillus pentosus strain S-PT84 (S-PT84) might show anti-stress activity and ameliorate stress-induced immune suppression in mice. Stress of mice induced an increase in serum corticosterone and a decrease in splenic natural killer activity and in the number of splenocytes versus control mice. However, these changes were not observed in stressed mice that had been administered S-PT84. Furthermore, interleukin (IL)-12 and IL-10 production, which was downregulated in lipopolysaccharide-activated macrophages from stressed mice, was maintained at control levels in the macrophages of stressed mice that had been fed S-PT84. Interferon-γ production, which was downregulated in concanavalin A-activated splenocytes from stressed mice, tended to be maintained at control levels in stressed mice that had been fed S-PT84, although IL-4 production by these cells was not influenced by S-PT84 administration. Additionally, reduced glutathione (GSH) levels were decreased in serum and peritoneal macrophages from stressed mice versus controls, but these GSH levels were significantly higher in stressed animals that had been administered S-PT84 compared with those that had not. These results suggest that S-PT84 exerts anti-stress activity through immune modulation and/or antioxidative activity.
... In our study, GSH, the most abundant antioxidant thiol present in mammalian cells, was decreased in rats exposed to PUS, neonatal poly (I:C) and poly(I:C) + PUS. Previous experiments have shown that immobilization stress in rodents induces generation of reactive oxygen species and decreases endogenous antioxidant defenses, which can be attenuated by extracellular administration of antioxidant GSH [45]. Decreased brain levels of GSH is also a core brain alteration observed in animal models of schizophrenia [8,46] and in schizophrenia postmortem patients [39]. ...
A ‘two-hit’ hypothesis of schizophrenia as an animal model: involvement of brain oxidative alterations
... It is well known that oxidative stress plays a role in the pathogenesis of anxiety and stress (Zafir and Banu, 2007). The association between stress and disease in which reactive oxygen species are involved have been established (Liu et al., 1994). Stress also cause the formation of oxidants and induce oxidative change to lipids, resulting in alterations in membrane functions, protein damage, and reduction in intracellular antioxidants defence in different areas of the brain. ...
... Various stressors viz. immobilization [44,45], restraint [46] and cold stress [47] are known to induce oxidative stress. However an animal model which can be used to get results within a short duration (1 day) was used in our present study, wherein 2 h after restraint there was a significant decrease in plasma total antioxidant activity compared to initial level (0 h) and it was further significantly decreased 4 h after forced swimming exercise. ...
The rhizome of Acorus calamus, an herb widely used in Indian system of medicine for many ailments including epilepsy, mental illness and rheumatism, was subjected to soxhlet extraction to elucidate antioxidant property of different solvent extracts using in vitro assays. The benzene extract was most potent in scavenging hydroxyl and superoxide radicals and in reducing 1,1-diphenyl-2-picryl hydrazyl and ferric reducing antioxidant power. In addition the benzene extract prevented oxidative damage to DNA and mitochondria. It was also effective in preventing stress -induced decrease in total plasma anti-oxidant activity as determined in vivo using rat model wherein stress was induced by exposing to restraint and forced swimming. The minimum effective dose of the benzene extract was 5mg/kg body weight (oral), and at this dose, its effect was similar to the same dose of a standard anti-oxidant, ascorbic acid. The study for the first time, clearly demonstrates a potent anti-oxidant activity of A. calamus combining in vitro and in vivo results. Hence, the therapeutic value of this herb maybe due to its anti-oxidant property.
... Obesity is a pro-inflammatory state that leads to increased oxidative stress markers, such as lipid peroxidation or malondialdehyde (MDA) and diminished antioxidant enzymes like reduced glutathione (GSH) in the brain (Esposito et al., 2006). The role of oxidative stress induced damage in the pathogenesis of depression, anxiety and other psychiatric disorders is reported earlier (Schiepers et al., 2005;Liu et al., 1994). ...
In our earlier study we reported the antidepressant activity of ondansetron in obese mice. The present study investigates the effect of ondansetron on depression and anxiety associated with obesity in experimental mice with biochemical evidences. Male Swiss albino mice were fed with high fat diet (HFD) for 14weeks to induce obesity. Then the subsequent treatment with ondansetron (0.5 and 1mg/kg, p.o.), classical antidepressant escitalopram (ESC) (10mg/kg, p.o.) and vehicle (distilled water 10ml/kg, p.o.) was given daily once for 28days. Behavioral assay for depression including sucrose preference test, forced swim test (FST) and anxiety such as light dark test (LDT), hole board test (HBT) were performed in obese mice. Furthermore, in biochemical estimations oral glucose tolerance test (OGTT), plasma leptin, insulin, corticosterone, brain oxidative stress marker malonaldehyde (MDA), antioxidant reduced glutathione (GSH) and serotonin assays were performed. Results indicated that HFD fed obese mice showed severe depressive and anxiety-like behavior. Chronic treatment with ondansetron inhibited the co-morbid depression and anxiety in obese mice by increasing sucrose consumption in sucrose preference test and reducing the immobility time in FST, increasing time and transitions of light chamber in LDT, improving head dip and crossing scores in HBT compared to HFD control mice. Ondansetron in obese mice inhibited glucose sensitivity in OGTT, improved plasma leptin and insulin sensitivity, reversed hypothalamic pituitary adrenal (HPA) axis hyperactivity by reducing the corticosterone concentration, restored brain pro-oxidant/anti-oxidant balance by inhibiting MDA and elevating GSH concentrations and facilitated serotonergic neurotransmission. In conclusion, ondansetron reversed the co-morbid depression and anxiety associated with obesity in experimental mice by attenuating the behavioral and biochemical abnormalities.
Copyright © 2015. Published by Elsevier Inc.
... Stress is often associated with psychiatric (depression, anxiety, and panic) and neurodegenerative disorders (Alzheimer's disease, Parkinson's disease, etc.). Oxidative stress, a condition involving a mishandled excessive formation of reactive oxygen and nitrogen species (ROS/RNS), produces damage of different molecules, organs and tissues, and it has been documented in studies using different models of stress in animals [16,24,25,41,43]. ...
This simple study was designed to investigate whether acute restraint stress can generate changes in behavioral tests and hippocampal endpoints of oxidative stress in rats, and if the antioxidant S-allyl cysteine (SAC) can prevent these alterations.
We evaluated motor activity, forced swimming and anxiety behavior, as well as the hippocampal levels of lipid peroxidation and the activities of glutathione-related enzymes in animals submitted to mild immobilization. The effect of SAC (100 mg⁄ kg, i.p.), given to rats every day 30 minutes before starting the immobilization session, was also investigated. Immobilization (restraint) stress was induced for a period of 6 h per day for five consecutive days.
Our results indicate that, under the tested conditions, acute restraint stimulates compensatory behavioral tasks (motor activity, anxiety and forced swimming) to counteract the stressing conditions prevailing, and selectively increased the levels of lipid peroxidation and the enzyme activities of glutathione-S-transferase (GST) and glutathione peroxidase (GPx) in the hippocampus also as adaptive responses. SAC exhibited preventive effects in the stressed group as it improved behavior, reduced lipid peroxidation and prevented the increase of GST and GPx activities, suggesting that this antioxidant blunted primary pro-oxidative stimuli induced by restraint stress.
Findings of this work also confirm that the use of antioxidants such as SAC can provide effective protection against the acute oxidative damage associated with anxiety produced by stressing conditions.
Copyright © 2015. Published by Elsevier Inc.
... Free radicals are highly reactive moieties, playing an important role in health and disease. The brain is especially vulnerable to free radical-induced damage because of its high oxygen consumption, abundant lipid content and low levels of enzymatic and non-enzymatic antioxidants [2]. ...
HE aim of the present study was to investigate the effects of taurine administration on biochemical parameters in Wistar rats subjected to acute restraint stress. Twenty four Wistar rats were divided into four groups of six rats each. The control group received distilled water and the other treatment groups were administered taurine at 100, 200 and 400 mg/kg. The treatments were administered once daily by oral gavage. The rats were sacrificed brain and blood samples were collected after 14 days. The brain malondialdehyde, Acetylcholineterase concentrations and the activities of brain antioxidant enzymes were evaluated. The serum samples were analyzed for proteins and enzymes concentration. The results indicated that acute restraint stress induced biochemical alterations in the rats. It is hypothesized that taurine might have decreased the alterations in the biochemical parameters through its antioxidant properties. It is concluded that taurine may be a useful prophylactic agent against biochemical alterations in individuals that are constantly exposed to one form of stress or another, as it counteracted the restraint stress-induced lipid peroxidation and maintained the antioxidant defense system to near normal.
... It is well known that oxidative stress plays a role in the origin and effects of anxiety and stress [35] . The associations between stresses and diseases in which reactive oxygen species are involved have been established [36] . Stress also causes the formation of reactive oxygen species and oxidants and induces oxidative damage to lipids, resulting in alterations in membrane functions, protein damage, and reduction in intracellular antioxidant defence in different areas of the brain. ...
The antidepressant effects of the flavonoid-rich fraction of Monodora tenuifolia seed extract were examined by assessing the extent of attenuation of behavioural alterations and oxidative damage in the rats that were stressed by forced swim test. Compared with the model control group, the altered behavioural parameters were attenuated significantly (P < 0.05) in the group treated with the flavonoid-rich fraction (100 and 200 mg·kg(-1)), comparable to the group treated with the standard drug, fluoxetine (10 mg·kg(-1)). The flavonoid-rich fraction and fluoxetine improved significantly (P < 0.05) the activities of the antioxidant enzymes such as superoxide dismutase and catalase as well as other biochemical parameters such as reduced glutathione, protein, and nitrite in the brain of the stressed rats. These results suggested that the flavonoid-rich fraction of Monodora tenuifolia seed extract exerted the antidepressant-like effects which could be useful in the management of stress induced disease.
Copyright © 2015 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.
... Oxidative stress was observed in hypothalamus [56,57] and hippocampus [42]. However, the CP method has methodological issues that predispose the animals to suffer from isolation and immobilization stress, conditions that generate oxidative stress [74,75]. The MSP with MLP method was the PSD protocol with the proper fashion to control possible environmental variables that generate stress. ...
Because the function and mechanisms of sleep are partially clear, here we applied a meta-analysis to address the issue whether sleep function includes antioxidative properties in mice and rats. Given the expansion of the knowledge in the sleep field, it is indeed ambitious to describe all mammals, or other animals, in which sleep shows an antioxidant function. However, in this article we reviewed the current understanding from basic studies in two species to drive the hypothesis that sleep is a dynamic-resting state with antioxidative properties. We performed a systematic review of articles cited in Medline, Scopus and Web of Science until March 2015 using the following search terms: Sleep or sleep deprivation and oxidative stress, lipid peroxidation, glutathione, nitric oxide, catalase or superoxide dismutase. We found a total of 266 studies. After inclusion and exclusion criteria, 44 articles were included, which are presented and discussed in this study. The complex relationship between sleep duration and oxidative stress is discussed. Further studies should consider molecular and genetic approaches to determine whether disrupted sleep promotes oxidative stress.
... Literatürde, yaygın anksiyete bozukluğunda MDA ve E vitamini düzeylerini araştıran bir çalışmaya rastlanmamıştır. Ancak, deney hayvanlarıyla yapılan çalışmalarda, strese maruz bırakılan ratlarda plazma antioksidan savunma sisteminde azalma gösterilmiştir (33). ...
Altered levels of malondialdehyde and vitamin E in major depressive disorder and generalized anxiety disorder Introduction: Reactive oxygen species (ROS) may play a role in some neuropsychiatric disorders. There is some evidence that the activation of immune-inflammatory processes, an increase in monoamines catabolism and abnormalities in lipid compounds may cause overproduction of ROS and lipid peroxidation. These phenomena may be related to pathophysiology of major depressive disorder and generalized anxiety disorder. Malondialdehyde (MDA) is the end product of lipid peroxidation. Vitamin E is thought to play an important role as an antioxidant against lipid peroxidation. This study aims to investigate the role of oxygen radicals in the etiology of major depressive disorder and generalized anxiety disorder. Method: Plasma MDA and vitamin E levels of patients with major depressive disorder (n=42) and generalized anxiety disorder (n=37) were compared with healthy controls (n=38). To assess depressive symptoms and anxiety symptoms, Hamilton Depression Scale and Hamilton Anxiety Scale were applied. Results: Patients with major depressive disorder and generalized anxiety disorder had higher MDA and lower vitamin E levels than those of healthy controls. Differences between the patient and the control groups according to these two parameters were found statistically significant. Conclusion: Our results support the hypothesis that oxidative stress may affect depressive and anxiety symptoms. As a result, free radical damage and deficiency of antioxidant defence systems may have an important role in major depressive disorder and generalized anxiety disorder.
... In the present study, GSH demonstrated its antioxidant effect when it was able to partially reverse the enzymatic activity inhibited by imidacloprid at the two highest concentrations tested (100 and 1000 μM). Other studies have shown the benefits of GSH treatment, resulting in a reduction in the oxidant burden at the alveolar epithelial surface in the idiopathic pulmonary fibrosis [41], attenuation of reactive oxygen species generation and increased antioxidant defenses [42], attenuation of lipid peroxidation [43] and prevention of neurotoxicity induced by treatment with oxaliplatin without reducing the clinical activity of oxaliplatin [44]. ...
Neonicotinoids represent the most used class of insecticides worldwide, and their precursor, imidacloprid, is the most widely marketed. The aim of this study was to evaluate the effect of imidacloprid on the activity of hepatic δ-aminolevulinate dehydratase (δ-ALA-D), protective effect of potential antioxidants against this potential effect and presence of chemical elements in the constitution of this pesticide. We observed that δ-ALA-D activity was significantly inhibited by imidacloprid at all concentrations tested in a dose-dependent manner. The IC50 value was obtained and used to evaluate the restoration of the enzymatic activity. δ-ALA-D inhibition was completely restored by addition of dithiotreitol (DTT) and partly by ZnCl2, demonstrating that the inhibition occurs by oxidation of thiol groups and by displacement of the Zn (II), which can be explained by the presence of chemical elements found in the constitution of pesticides. Reduced glutathione (GSH) had the best antioxidant effect against to δ-ALA-D inhibition caused by imidacloprid, followed by curcumin and resveratrol. It is well known that inhibition of the enzyme δ-ALA-D may result in accumulation of its neurotoxic substrate (δ-ALA), in this line, our results suggest that further studies are needed to investigate the possible neurotoxicity induced by neonicotinoids and the involvement of antioxidants in cases of poisoning by neonicotinoids.
... For instance, oxidative stress is involved in the pathogenesis of hypercholesterolemia 2 , while biological stress also plays a significant role in the susceptibility, progress, and outcome of CVD 3 . On the other hand, there is also a connection between biological stressors and increased production of free radicals and oxidative damage 4 ...
Hyperlipidemia and stress are important factors affecting cardiovascular health in middle-aged individuals.
We investigated the effects of N-acetylcysteine (NAC) and sesame oil on the lipidemic status, liver architecture and the hypothalamic-pituitary-adrenal (HPA) axis of middle-aged mice fed a cholesterol-enriched diet. We randomized 36 middle-aged C57bl/6 mice into 6 groups: a control group, a
cholesterol/cholic acid diet group, a cholesterol/cholic acid diet group with NAC supplementation, a
cholesterol/cholic acid diet enriched with 10% sesame oil and two groups receiving a control diet enriched
with NAC or sesame oil. NAC administration prevented the onset of the disturbed lipid profile, exhibiting
decreased lipid peroxidation and alkaline phosphatase (ALP) levels, restored nitric oxide bioavailability and
reduced hepatic damage, compared to non-supplemented groups. High-cholesterol feeding resulted in
increased glucocorticoid receptors (GR) levels, while NAC supplementation prevented this effect. NAC
supplementation presented significant antioxidant capacity by means of preventing serum lipid status
alterations, hepatic damage, and HPA axis disturbance due to high-cholesterol feeding in middle-aged mice.
These findings suggest a beneficial preventive action of plant-derived antioxidants, such as NAC, on lipid
metabolism and on the HPA axis.
... Long term emotional stress activated glu-tathione peroxidase, and activation was accompanied by a decrease in superoxide dismutase and glutathione transferase activities (4). Immobilization stress is followed by an increase of lipid peroxidation, measured in plasma and brain, and in the inhibition of antioxidant enzymes (5)(6)(7). Studies of cytosolic fractions of cerebral cortex also demonstrated that there was a significantly greater increase in lipid peroxidation and protein oxidation after immobilization stress (8). ...
CuZn superoxide dismutase (CuZnSOD) activity in hippocampus and brain cortex of Wistar male rats exposed to acute stress (immobilization or cold for 2 h), chronic stress (isolation or social crowding for 21 days), or to their various combinations was examined. The highest CuZnSOD activity in both brain structures was observed in chronic isolation and it decreased after additional exposure to either of the acute stressors. Contrary to that, chronic crowding had no effect on CuZnSOD activity in hippocampus, while in brain cortex it even caused the suppresion of enzyme activity. Additional exposure to acute stresses differently affected the enzyme activity depending on the brain region and type of stress: immobilization increased the activity of CuZnSOD in hippocampus, while cold de-creased it in cortex. Acute stress by immobilization caused the elevation of CuZnSOD ac-tivity in cortex, and acute cold exposure decreased enzyme activity in hippocampus. The observed region specific alterations of SOD activity indicate that neuroendocrine stress most probably generate cellular imbalance between production and elimination of ROS, which may provide some insights into a variety of neuropsychological processes as well as their treatment.
... This coincided with increased plasma malondialdehyde production, a widely accepted general indicator of oxidative damage. Liu et al. (1994) demonstrated a significant increase in plasma lipid peroxidation using similar methods following 6 h of immobilization stress which could be reversed by reduced glutathione treatment, implicating directly the causative role of oxidative damage. ...
Abstract Acute stress leads to the rapid secretion of glucocorticoids, which accelerates cellular metabolism, resulting in increased reactive oxygen and nitrogen species generation. Although the nitrergic system has been implicated in numerous stress-related diseases, the time course and extent of nitrosative changes during acute stress have not been characterized. Outbred male Wistar rats were randomly allocated into control (n=9) or 120 minute acute immobilization stress (n=9) groups. Serial blood samples were collected at 0 (baseline), 60, 90, and 120 minutes. Plasma corticosterone concentrations increased by approximately 350% at 60, 90, and 120 (p<0.001) minutes of stress. The production of nitric oxide, measured as the benzotriazole form of 4-amino-5-methylamino-2',7'-difluorofluorescein, increased during stress exposure by approximately 5%, 10%, and 15% at 60 (p<0.05), 90 (p<0.01) and 120 (p<0.001) minutes respectively compared to controls. Nitric oxide metabolism, measured as the stable metabolites nitrite and nitrate, showed a 40% to 60% increase at 60, 90, and 120 (p<0.001) minutes of stress. The oxidative status of 2', 7'-dichlorofluorescein in plasma was significantly elevated at 60 (p<0.01), 90, and 120 (p<0.001) minutes. A delayed decrease of approximately 25% in the glutathione redox ratio at 120 minutes (p<0.001) also indicates stress-induced cellular oxidative stress. The peroxidation of plasma lipids increased by approximately 10% at 90 (p<0.05) and 15% at 120 (p<0.001) minutes, indicative of oxidative damage. It was concluded that a single episode of stress causes early and marked changes of both oxidative and nitrosative status sufficient to induce oxidative damage in peripheral tissues.
... However, Ghizoni and coworkers showed that acute restraint stress via the inhibition of nitric oxide synthase led to an increase in GSH levels in the cerebellum after 2 and 4 h of immobilization, but not in the cerebral cortex, striatum, and hippocampus (Ghizoni et al., 2006). Evidences indicate that pretreatment with antioxidants, GSH, alpha-tocopherol and N-acetyl cysteine reduced the stress-induced oxidative stress in rats (Liu et al., 1994;Chakraborti et al., 2008). ...
The aim of this study was to evaluate the effect of acute and chronic physical and psychological stressors on the induction of oxidative stress in male rat liver. Male Wistar rats were randomly divided into 3 groups as following: control, physical and psychological stress groups. Stress was induced by communication box for one (acute), fifteen and thirty (chronic) days. Once stressor periods ended, rats were anesthetized and their liver dissected out for later assessments. Exposure to physical stress enhanced liver superoxide dismutase (SOD) (19.44 %) and glutathione S-transferase (GST) (21.84 %) activities and decreased glutathione (GSH) (30.03 %) level on the 1st day (p<0.05). SOD (24.13 and 18.43 %) and GST (27.77 and 21.27 %) activities were significantly increased, while catalase activity (29.74 and 24.41 %) and GSH level (35.05 and 31.05 %) were decreased in psychological stress group after 1 and 15 days (p<0.01 and p<0.05) compared to the 1st day value in control group, respectively. Psychological stress induced an increase in liver malondialdehyde (MDA) (46 %) and plasma corticosterone (36 %) levels on the 1st day (p<0.05). However, all parameters returned to their basal value after 30 days of stress.
The results suggest that exposure to acute physical and psychological stressors induce the production of reactive oxygen species and oxidative stress in rat liver due to GSH depletion and the decreased catalase activity. The elevation of lipid peroxidation and corticosterone level in acute psychological stress may lead to more profound oxidative damage than acute physical stress. Moreover, cell protection in hepatic tissue of chronically stressed rats is indicative of possible late adaptation of the animals to stress.
... Consequently, stressed animals exposed to vehicle odor demonstrated an increase of approximately 15% in plasma lipid peroxidation. Despite the short duration of stress, this increase is similar to that seen in some animal models of chronic stress and is in agreement with previous acute stress studies (Liu et al. 1994;Tagliari et al. 2010). Praescent exposure during stress was effective in preventing all of these stress-induced redox alterations. ...
In this study, we measured typical stress markers in addition to oxidative status and reduced glutathione in erythrocytes,
and plasma lipid peroxidation of restraint-stressed animals exposed to a combination of plant-derived odors (0.03% Z-3-hexen-1-ol, 0.03% E-2-hexenal, and 0.015% α-pinene in triethyl citrate). Male Wistar rats aged 6–7 weeks postnatal were exposed to vehicle (triethyl
citrate, n = 12), plant-derived odors (n = 12), or 1% propionic acid odor (n = 12) under control or stress conditions, and blood samples were collected. Restraint stress increased plasma glucose and
plasma corticosterone concentrations by approximately 10% (P < 0.01) and 125% (P < 0.001), respectively, in vehicle-exposed animals. Similar increases were observed in animals exposed to a 1% propionic
acid odor, indicating the novelty of odor exposure does not alter stress responsiveness. There was also an increase of approximately
15% in both erythrocytic oxidative status (P < 0.001) and plasma lipid peroxidation (P < 0.05), and a decrease of approximately the same magnitude in reduced glutathione (P < 0.05) in restrained animals with vehicle exposure. There were no differences observed between control and stress treatment
with plant-derived odor exposure in any of the measured parameters. It was concluded that exposure to plant-derived odors
reduce corticosterone, glucose, and redox responses elicited by psychological stress.
... Among the organs in the human body, the CNS takes more than its share of oxidative abuse [1,12,13]. The main factors that contribute 2 Evidence-Based Complementary and Alternative Medicine to the vulnerability of brain to oxidative damage include high content of polyunsaturated fatty acids in the membranes and low levels of enzymatic and nonenzymatic antioxidants [14]. One of the most important consequences of the generation of free radical is the peroxidation of membrane lipids. ...
The prophylactic or curative antioxidant efficacy of crude extract and the active constituent of S. nigrum leaves were evaluated in modulating inherent antioxidant system altered due to immobilization stress in rat brain tissues, in terms of measurement of glutathione (GSH), lipid peroxidation (thiobarbituric acid reactive substances, TBARS), and free radical scavenging enzymes activities. Rats were treated with single dose of crude extract of S. nigrum prior to and after 6 h of immobilization stress exposure. Exposure to immobilization stress resulted in a decrease in the brain levels of glutathione, SOD, GST, and catalase, with an increase in thiobarbituric acid reactive substances (TBARS) levels. Treatment of S. nigrum extract and its active constituents to both pre- and poststressed rats resulted in significant modulation in the above mentioned parameters towards their control values with a relative dominance by the latter. Brain is vulnerable to stress induced prooxidant insult due to high levels of fat content. Thus, as a safe herbal medication the S. nigrum leaves extract or its isolated constituents can be used as nutritional supplement for scavenging free radicals generated in the brain due to physical or psychological stress or any neuronal diseases per se.
Objectives:
Apoptosis is common and often comorbid with aging and stress-related mood disorders. Evidence suggests that fresh mitochondria could reverse age-related dysfunctions in organs, especially in the brain. Therefore, this study investigated the effect of young mitochondria administration on the apoptosis process in the prefrontal cortex (PFC) of aged rats exposed to chronic stress.
Materials and methods:
Aged (22 months old) male rats were randomly assigned into four groups: aged control (AC), aged rats treated with young mitochondria (A+M), aged rats subjected to chronic stress for four weeks (A+St), and aged rats subjected to chronic stress and treated with young mitochondria (A+St+M). A+M and A+St+M groups received a single ICV injection (10 μl) of fresh mitochondria isolated from the brain of young rats for five minutes (2 µl/min). Finally, the levels of Malondialdehyde (MDA), Cytochrome c (Cyt c), Bax, Bcl-2, and Caspase-3 expression were investigated in the PFC.
Results:
Young mitochondria administration reduced neuronal apoptosis in the PFC, associated with down-regulation of MDA, Bax, and Caspase-3 and up-regulation of Bcl-2. Moreover, fresh mitochondria partially improved the chronic stress-induced mitochondrial dysfunction in aged rats, as indicated by reduced cytochrome c (Cyt c) release from the mitochondria.
Conclusion:
These results suggest mitotherapy could reverse cell viability and mitochondrial dysfunction-induced apoptosis in the PFC tissue of aged rats subjected to stressful stimuli.
Stress intervenes in the brain’s capability to encode and regain information from a person, it alters the biochemical parameters in specific regions of the brain can cause long-term damage to various parts of brain. The present investigations aid in understanding the effect of the Prunus amygdalus nut extract on CUS induced memory deficits in rats. The methanolic extract with an antioxidant potential (~ 60%) and was selected for in vivo analysis. CUS was induced in rats using different stress paradigms for 10 days. On day 11 and 12, acquisition trials for memory evaluation were performed using Morris Water Maze. On day 13 and 10 days later on, i.e. day 23, short-term and long-term memory retrievals trials were evaluated, respectively. Treatment groups were given test methanolic extract an hour before the subjection of CUS. Biochemical estimations and histopathological studies were carried out using brain tissue homogenate and brain tissue section, respectively. CUS altered the Transfer Latency time in both acquisition and retrieval trials, indicating memory impairment, which was reduced significantly in extract-treated groups. Administration of P. amygdalus nut methanolic extract protected the rat brains against CUS-induced neuroinflammatory changes. The observed beneficial effects could be attributed to the antioxidant potential of P. amygdalus.
Post-traumatic stress disorder (PTSD) may occur after exposure to stressful, fearful or troubling events. Until now, there is no curable medication for this disorder. Cerebrolysin is a neuropeptide, which has an important role in the treatment of vascular dementia. In this study, the probable protective effect of cerebrolysin on PTSD-induced memory impairment was investigated. To induce PTSD, the single prolonged stress (SPS) model was used. Rats were allocated into four groups: control (vehicle-treated), CBL (administrated cerebrolysin 2.5 ml/kg by intraperitoneal route for 4 weeks), SPS (as a model of PTSD and administered vehicle), and CBL-SPS (exposed to SPS and administered cerebrolysin for 4 weeks). Learning and memory were assessed using the radial arm water maze (RAWM). Results showed that SPS impaired both short- and long- term memories; and chronic cerebrolysin administration prevented such effect. Cerebrolysin also prevented decreases in hippocampal GSH levels and GSH/GSSG ratios, and increased GSSG and TBARs, levels induced by PTSD. In conclusion, a protective effect of cerebrolysin administration against SPS model of PTSD induced short- and long- term memory impairment was characterized. This protection could be accomplished, at least partly, by prevention of PTSD induced increase in oxidative stress in the hippocampus via the use of cerebrolysin.
Sleep deprivation (SD) influences physiological processes such as cognitive function. The balance of oxidant and
antioxidant markers, neurotrophic factors and magnesium are affected by sleep deprivation but there is no
difference between pre and post training sleep deprivation. This study was designed to investigate memory
retrieval and biochemical factors such as oxidant and antioxidant enzyme, brain-derived neurotrophic factor
(BDNF) and magnesium levels in the hippocampus following pre and post-training sleep deprivation.
Male Wistar rats (weighing 200 ± 20 g) in below groups were used: control 1, 24, 48 and 72 h SD before
training groups, control2, 24 h SD1 after training (being evaluated 24 h after training) and SD2 24 after training
(being evaluated 48 h after training). Memory was evaluated 90 min, 24 h or 48 h after training by step-through
passive avoidance apparatus. Multiple platforms method was used to induce SD. Oxidant and antioxidant
markers including glutathione (GSH), glutathione reductase (GPx), malonedialdehyde (MDA), Total antioxidant
concentration, catalase, superoxide dismutase (SOD), magnesium and BDNF were assessed in the hippocampus
or/and brain.
72 h pre-training SD impaired short and long-term memory significantly. There was no significant difference
in hippocampus oxidant and antioxidant markers compared to control. Hippocampal BDNF and magnesium did
not show any changes in all SD groups.
Lack of correlation between memory impairment and levels of BDNF, magnesium and/or oxidant and antioxidant
balance in the hippocampus is likely to be related to animal locomotor activity in the multiple platforms
method. More research is needed to clarify the role of neurochemical systems.
Post-traumatic stress disorder (PTSD) is a mental health disorder that can develop after a terrifying or life threatening event. Multiple symptoms are noticed in patients with PTSD including cognitive impairment, which was shown to be is associated with oxidative stress. Tempol is a highly efficient membrane-permeable antioxidant. In this study, we investigated the possible protective effect of tempol on PTSD-induced memory impairment. To test this hypothesis, we used single prolonged stress (SPS) model (2h restrain, 20min forced swimming, 15min rest, and 1-2min diethyl ether exposure) as a model of PTSD. Rats were randomly assigned into four groups: control (provided distilled water), tempol (provided tempol; 80mg/kg/day by oral gavage for 4weeks), SPS (exposed to prolonged stress and administered distilled water) and tempol/SPS (exposed to prolonged stress and administered tempol for 4weeks). We used radial arm water maze to test spatial learning and memory functions and enzyme-linked immunosorbant assay (ELISA) to measure levels of oxidative stress biomarkers in the hippocampus. Results showed that SPS model of PTSD impaired both short and long-term memories (P<0.05), and chronic tempol administration prevented such effect. Tempol also prevented decreases in hippocampal catalase, and SOD activities, GSH/GSSG ratio and increases TBARS levels, which were all impaired by SPS model of PTSD (P<0.05). In conclusion, we suggest a protective effect of tempol administration against SPS model of PTSD-induced short- and long- term memory impairment, and we believe that this protective effect of tempol is accomplished, at least partly, through prevention of alternation in oxidative stress in the hippocampus.
Immobilization stress for 6 hours induced hemorrhagic erosion in the rat stomach. Hydroxyl radicals significantly increased in the pons-medulla oblongata in stressed rats. Mitochondrial superoxide dismutase (SOD) activity was enhanced in the midbrain but was lowered in the cortex, hippocampus and cerebellum in stressed rats. Thiobarbituric acid reactive substances increased by stress in the cortex and midbrain. These findings suggested that immobilization stress generated hydroxyl radicals and accelerated lipid peroxidation, and affected mitochodrial SOD activity, which may lead to neuronal damage in stressed rats.
This work aims to study the oral effect of VE administration (300 mg/kg b.wt.) to normal and ACR-intoxicated rats. The level of monoamines (norepinephrine; NE, dopamine; DA and serotonin; 5-hydroxytryptamine, 5-HT) in cerebral cortex, thalamus & hypothalamus, midbrain, pons & medulla oblongata and cerebellum were determined.
Alcohol-use disorders are common in all developed countries and are more prevalent in men than women, with lower but still substantial rates in developing countries [1, 2]. Although rates of these disorders are lower in the Mediterranean countries (e.g. Greece, Italy and Israel) and higher in northern and eastern Europe (e.g. Russia and Scandinavia), they are responsible for a large proportion of the health-care burden in almost all populations [1, 2].
Stress is considered to be a causal agent of chronic degenerative diseases, such as cardiovascular disease, diabetes mellitus, arthritis and Alzheimer's. Chronic glucocorticoid and catecholamine release into the circulation during the stress response has been suggested to activate damage mechanisms, which in the long term produce metabolic alterations associated with oxidative stress and inflammation. However, the consequences of stress in animal models for periods longer than 40days have not been explored. The goal of this work was to determine whether chronic unpredictable mild stress (CUMS) produced alterations in the redox state and the inflammatory profile of rats after 20, 40, and 60days. CUMS consisted of random exposure of the animals to different stressors. The following activities were measured in the liver and pancreas: reduced glutathione (GSH), lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC), and protein oxidation. Similarly, serum cytokine levels (IL-6, TNF-α, IL-1β, and IL-10) were determined. CUMS activated the stress response from day 20 until day 60. In the liver and pancreas, GHS levels were decreased from day 40, whereas protein lipid peroxidation and protein oxidation were increased. This is the first work to report that the pancreas redox state is subject to chronic stress conditions. The TAC was constant in the liver and reduced in the pancreas. An increase in the TNF-α, IL-1β, and IL-6 inflammatory markers and a decrease in the IL-10 level due to CUMS was shown, thereby resulting in the generation of a systemic inflammation state after 60days of treatment. Together, the CUMS consequences on day 60 suggest that both processes can contribute to the development of chronic degenerative diseases, such as cardiovascular disease and diabetes mellitus. CUMS is an animal model that in addition to avoiding habituation activates damage mechanisms such as oxidative stress and low-grade chronic inflammation, which allows the study of physio-pathological stress aspects over prolonged time periods of at least 60days.
The effects of starvation and cold-restraint stress on lipid peroxidation, lipid levels and on susceptibility of VLDL+LDL fractions to autooxidation were investigated in the plasma of rats. The content of protein carbonyl groups was also measured after starvation and cold-restraint stress. The susceptibility of VLDL+LDL to autooxidation, the content of protein carbonyl groups, total cholesterol, HDL-cholesterol and LDL-cholesterol levels remained unchanged but triglyceride and thiobarbituric acid reactive substances (TBARS) levels were found increased after 48 h of starvation. There were significant increases in the susceptibility of VLDL+LDL to autooxidation and TBARS levels in cold-restraint stress group when compared with values obtained from starvation group. In addition, cold-restraint stress elevated total cholesterol, LDL-cholesterol and reduced HDL-cholesterol but did not change triglyceride levels as compared with starvation group. Our results suggest that stress inducing lipid peroxidation may contribute to the initiation and/or progression of atherosclerosis.
The aim of the study was to determine plasma levels of vitamin C and reduced glutathione (GSH) in sows between the day 14 prepartum and day 14 postpartum. The study involved twenty-four sows of three breeds - Polish Large White (PLW), Polish Landrace (PL) and PLWxPL, aged 1-3 years. All the animals were from one closed-cycle production farm. The mean vitamin C level on days 13-14 prepartum reached 0.49 +/- 0.19 mmol/g of protein and decreased significantly (P<0.05) at 24-48 h postpartum to 0.33 +/- 0.19 mmol/g of protein. On days 6-7 and 13-14 postpartum, the vitamin C level further decreased to 0.17 +/- 0.006 and 0.15 +/- 0.007 mmol/g of protein, respectively. The mean GSH level on days 13-14 before delivery was 0.071 +/- 0.009 mmol/g of protein and decreased significantly (P<0.05) at 24-48 h before delivery to 0.062 +/- 0.018 mmol/g of protein. In this period, the mean GSH level was similar to that observed during the first 24-48 h postpartum. On day 6-7 after delivery, the level of GSH reached the values observed on days 13-14 and 6-7 prepartum. On days 13-14 postpartum, the level of GSH was found to be 0.115 +/- 0.029 mmol/g of protein and was significantly higher (P<0.001) compared to that on days 13-14 prepartum. The findings suggest that porcine levels of vitamin C and glutathione decrease during the periparturient period, which may lead to a decreased antioxidant defence system and an imbalance in redox homeostasis.
Abstract We hypothesized that acute stress would induce endothelial dysfunction. Male Wistar rats were restrained for 2 h within wire mesh. Functional and biochemical analyses were conducted 24 h after the 2-h period of restraint. Stressed rats showed decreased exploration on the open arms of an elevated-plus maze (EPM) and increased plasma corticosterone concentration. Acute restraint stress did not alter systolic blood pressure, whereas it increased the in vitro contractile response to phenylephrine and serotonin in endothelium-intact rat aortas. NG-nitro-l-arginine methyl ester (l-NAME; nitric oxide synthase, NOS, inhibitor) did not alter the contraction induced by phenylephrine in aortic rings from stressed rats. Tiron, indomethacin and SQ29548 reversed the increase in the contractile response to phenylephrine induced by restraint stress. Increased systemic and vascular oxidative stress was evident in stressed rats. Restraint stress decreased plasma and vascular nitrate/nitrite (NOx) concentration and increased aortic expression of inducible (i) NOS, but not endothelial (e) NOS. Reduced expression of cyclooxygenase (COX)-1, but not COX-2, was observed in aortas from stressed rats. Restraint stress increased thromboxane (TX)B2 (stable TXA2 metabolite) concentration but did not affect prostaglandin (PG)F2α concentration in the aorta. Restraint reduced superoxide dismutase (SOD) activity, whereas concentrations of hydrogen peroxide (H2O2) and reduced glutathione (GSH) were not affected. The major new finding of our study is that restraint stress increases vascular contraction by an endothelium-dependent mechanism that involves increased oxidative stress and the generation of COX-derived vasoconstrictor prostanoids. Such stress-induced endothelial dysfunction could predispose to the development of cardiovascular diseases.
We investigated the effect of hyperbaric oxygen therapy (HBOT) on rat muscles during tibial distraction osteogenesis (DO) at normal and hyperdistraction rates. Animals in groups 1 and 2 were distracted by 0.5 mm/day and those in groups 3 and 4 by 1 mm/day. Groups 2 and 4 received HBOT during distraction. Group 5 served as control. Superoxide dismutase (SOD; U/g protein), malondialdehyde (nmol/g protein), glutathione (mmol/g protein), and protein levels (g/dl) were determined. SOD was significantly higher in group 2 (4.59 ± 0.97) than in controls (2.19 ± 0.7) (P = 0.0001), and lower in group 4 (3.74 ± 1.70) than in group 2 (P = 0.011). Malondialdehyde was significantly higher in group 2 (0.72 ± 0.23) than in controls (0.38 ± 0.10) (P = 0.005). Total protein levels were better preserved with HBOT in distracted muscles: group 2 (3.24 ± 0.37) vs. group 1 (1.88 ± 0.60), and group 4 (3.45 ± 0.70) vs. group 3 (2.03 ± 0.75) (both P = 0.0001). Numbers of fibres were lower in group 1 (4.88 ± 0.59) than in group 2 (6.07 ± 0.86), and in group 3 (5.13 ± 0.36) than in group 4 (6.14 ± 0.74) (both P = 0.001). Numbers of nuclei were higher in group 1 (11.29 ± 2.47) than in group 2 (9.03 ± 1.53) (P = 0.04), and in group 3 (12.43 ± 3.32) than in group 4 (9.08 ± 1.58) (P = 0.001). Fibres and nuclei with HBOT were similar to those of controls. HBOT decreased the inflammatory cell infiltrate for group 1 (19.8 ± 8.54) vs. group 2 (4.2 ± 2.53) and group 3 (36.54 ± 11.29) vs. group 4 (21.5 ± 9.23) (both P = 0.001). HBOT improves the adaptation of distracted muscle by increasing fibres and antioxidants while decreasing inflammation.
The inconsistent therapeutic outcome necessitates designing and identifying novel therapeutic interventions for depression. Hence, the present study deals with the investigation of antidepressant-like effects of a novel 5-HT
Animals were subjected to different stressors for a period of 28 days. On day 15 after the subsequent stress procedure, mice were administered with (4a) (2 and 4 mg/kg p.o.), escitalopram (10 mg/kg p.o.), or vehicle (10 mL/kg p.o.) until day 28 along with the CUMS. Thereafter, behavioral battery tests like locomotor score, sucrose preference test, forced swim test (FST), tail suspension test (TST), and elevated plus maze (EPM) were performed. Biochemical assays like lipid peroxidation, nitrite levels, reduced glutathione (GSH), catalase, and superoxide dismutase (SOD) were estimated in the mice brain homogenate.
(4a) Dose dependently attenuated the behavioral alterations by increasing the sucrose consumption, reducing the immobility time in FST and TST, increasing the open arm number of entries and time in EPM. Furthermore, biochemical alterations were reversed by (4a) as examined by reduced lipid peroxidation and nitrite levels and elevated antioxidant enzyme levels like GSH, catalase and SOD.
(4a) exhibits antidepressant potential by reversing the CUMS induced behavioral and biochemical changes in mice.
The SOD-like activity of several biological substances was evaluated by an ESR spin-trapping technique. Superoxide radicals (O2\
ewdot) were supplied enzymatically from a hypoxanthine–xanthine oxidase reaction to the evaluating system. By using a spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO), the generated O2\
ewdot was trapped stoichiometrically (1:1) as the spin adduct of O2\
ewdot (DMPO–O2−). When biological substances were added to the system, a decrease in the ESR signal intensities of the adducts was observed. This phenomenon could be explained as being an inhibition of adduct formation, and related to the reactivity of added biological substances with O2\
ewdot, called an SOD-like activity. By the method of kinetic competition with a 50% inhibitory dose (ID50), the second-order rate constant for the reaction between O2\
ewdot and biological substance was determined. These rate constants can be used as a measure of the reactivity.
We have shown recently that the temporal order of antioxidant consumption in human blood plasma exposed to a constant flux of aqueous peroxyl radicals is ascorbate = protein thiols greater than bilirubin greater than urate greater than alpha-tocopherol and that detectable lipid peroxidation starts only after ascorbate has been consumed completely. In this paper, we show that it is indeed ascorbate that completely protects plasma lipids against detectable peroxidative damage induced by aqueous peroxyl radicals and that ascorbate is the only plasma antioxidant that can do so. Plasma devoid of ascorbate, but no other endogenous antioxidant, is extremely vulnerable to oxidant stress and susceptible to peroxidative damage to lipids. The plasma proteins' thiols, although they become oxidized immediately upon exposure to aqueous peroxyl radicals, are inefficient radical scavengers and appear to be consumed mainly by autoxidation. Our data demonstrate that ascorbate is the most effective aqueous-phase antioxidant in human blood plasma and suggest that in humans ascorbate is a physiological antioxidant of major importance for protection against diseases and degenerative processes caused by oxidant stress.
The temporal disappearance in human blood plasma of endogenous antioxidants in relation to the appearance of various classes of lipid hydroperoxides measured by HPLC postcolumn chemiluminescence detection has been investigated under two types of oxidizing conditions. Exposure of plasma to aqueous peroxyl radicals generated at a constant rate leads immediately to oxidation of endogenous ascorbate and sulfhydryl groups, followed by sequential depletion of bilirubin, urate, and alpha-tocopherol. Stimulating polymorphonuclear leukocytes in plasma initiates very rapid oxidation of ascorbate, followed by partial depletion of urate. Once ascorbate is consumed completely, micromolar concentrations of hydroperoxides of plasma phospholipids, triglycerides, and cholesterol esters appear simultaneously, even though sulfhydryl groups, bilirubin, urate, and alpha-tocopherol are still present at high concentrations. Nonesterified fatty acids, the only lipid class in plasma not transported in lipoproteins but bound to albumin, are preserved from peroxidative damage even after complete oxidation of ascorbate, most likely due to site-specific antioxidant protection by albumin-bound bilirubin and possibly by albumin itself. Thus, in plasma ascorbate and, in a site-specific manner, bilirubin appear to be much more effective in protecting lipids from peroxidative damage by aqueous oxidants than all the other endogenous antioxidants. Hydroperoxides of linoleic acid, phosphatidylcholine, and cholesterol added to plasma in the absence of added reducing substrates are degraded, in contrast to hydroperoxides of trilinolein and cholesterol linoleate. These findings indicate the presence of a selective peroxidase activity operative under physiological conditions. Our data suggest that in states of leukocyte activation and other types of acute or chronic oxidative stress such a simple regimen as controlled ascorbate supplementation could prove helpful in preventing formation of lipid hydroperoxides, some of which cannot be detoxified by endogenous plasma activities and thus might cause damage to critical targets.
Aging in mammalian species appears to be the result of normal developmental and metabolic processes. In spite of the vast complexity of aging processes, relatively less complex processes such as longevity determinant genes (LDGs) may exist governing aging rate. Much experimental data exists indicating a causative role of oxyradicals in aging processes. In testing the hypothesis that antioxidants may represent LDGs, a positive correlation in the tissue concentration of specific antioxidants with life span of mammals was found. These antioxidants include superoxide dismutase, carotenoids, α-tocopherol, and uric acid. We also found that the resistance of tissues to spontaneous autoxidation and the amount of oxidative damage to DNA correlates inversely with life span of mammals. These results suggest a role of oxyradicals in causing aging and that the antioxidant status of an individual could be important in determining frequency of age-dependent diseases and duration of general health maintenance.
To examine the effects of increased O2 utilization on the glutathione antioxidant system in blood, eight moderately trained male volunteers were exercised to peak O2 consumption (VO2peak) and for 90 min at 65% of VO2peak on a cycle ergometer. Blood samples were taken during exercise, and for up to 4 days of recovery from submaximal exercise. During exercise to VO2peak, blood reduced glutathione (GSH) and total glutathione [GSH + oxidized glutathione (GSSG)] did not change significantly. Lactate (L), pyruvate (P), and L/P increased significantly from rest values (P less than 0.01). During prolonged submaximal exercise, GSH decreased 60% from control, and GSSG increased 100%. Total glutathione, glucose, pyruvate, and lactate concentrations and L/P did not change significantly during sustained exercise. During recovery, GSH and GSH/GSSG increased from exercise levels and significantly overshot preexercise levels, reaching maximum values after 3 days. Oxidation of GSH during submaximal exercise and its reduction in recovery suggest increased formation of active O2-. species in blood during physical exercise in moderately trained males.
Normal human plasma contains numerous high and low molecular mass redox active molecules that are able to react rapidly with organic and inorganic oxygen radicals. The ability of such plasma molecules to substantially inhibit, or delay, free radical mediated oxidation of added substrates has led to their classification as important biological antioxidants. Using phospholipids to detect organic oxygen radicals, and deoxyribose to detect inorganic oxygen radicals, we here show that the primary antioxidants of normal human plasma reside mainly in two plasma proteins representing no more than 4% of the total proteins present. The iron-binding properties of transferrin and the iron-oxidising properties of caeruloplasmin, at a reaction dilution of 1:50, offer considerable protection against organic and inorganic oxygen radicals generated by iron and ascorbate. Plasma thiol group-containing molecules, at concentrations well below those that would be required to compete with the detector molecule (based on known second order rate constants for reaction with hydroxyl radicals) inhibited damage to deoxyribose, but stimulated damage to phospholipids.
The antioxidant defense alteration in young and old senescence accelerated mice (SAM) was studied by examining superoxide dismutase (SOD) activity, thiobarbituric acid (TBA) reactivity, and reduced glutathione (GSH) level in brain and liver tissues. The changes were compared with those in age-paired ddY mice, a strain exhibiting normal aging. SAM mice showed an age-dependent increase in SOD activity in liver, and an age-dependent increase in TBA reactivity in both the brain and the liver; they also showed an age-dependent decrease in the GSH level in the brain and the liver. When compared with ddY mice, SAM mice showed a higher SOD activity in the brain (at both 3 and 11 months old), a lower GSH level in the liver (at 3 months old), and a higher TBA reactivity in the liver (at 3 months old). These findings suggest that the mechanism of senescence acceleration in SAM mice is to some extent related to free radical damage.
We developed a new technique for directly observing in vivo free radical information in the circulating blood of living rats using electron spin resonance (ESR) spectrometry without any labelling or trapping agents. It was found that a doublet peak spectrum was obtained following ferric citrate and ascorbic acid injection. The signals were confirmed in different ways to be due to ascorbic acid radicals. These results provide evidence to support the involvement of free radical intermediates in iron-ascorbic acid reactions, and further confirm the suggested mechanisms of both the adverse and protective effects of ascorbic acid in biological systems. Futhermore, this method of direct observations is a new application of ESR spectrometry to living animals.
The reaction of lipid peroxides in animal tissues with thiobarbituric acid was dependent on pH of the reaction mixture as was the case for linoleic acid hydroperoxide. The optimum pH was found to be 3.5. Taking this fact into consideration, a standard procedure for the assay of lipid peroxide level in animal tissues by their reaction with thiobarbituric acid was developed as follows. Ten percent ( tissue homogenate was mixed with sodium dodecyl sulfate, acetate buffer (pH 3.5), and aqueous solution of thiobarbituric acid. After heating at 95°C for 60 min, the red pigment produced was extracted with n-butanol-pyridine mixture and estimated by the absorbance at 532nm. As an external standard, tetramethoxy-propane was used, and lipid peroxide level was expressed in terms of nmol malondialdehyde. Using this method, the liped peroxide level in the liver of rats suffering from carbon tetrachloride intoxication was investigated. The results were in good agreement with previously reported data obtained by measuring diene content.
Nitric oxide (NO.), a potentially toxic molecule, has been implicated in a wide range of biological functions. Details of its biochemistry, however, remain poorly understood. The broader chemistry of nitrogen monoxide (NO) involves a redox array of species with distinctive properties and reactivities: NO+ (nitrosonium), NO., and NO- (nitroxyl anion). The integration of this chemistry with current perspectives of NO biology illuminates many aspects of NO biochemistry, including the enzymatic mechanism of synthesis, the mode of transport and targeting in biological systems, the means by which its toxicity is mitigated, and the function-regulating interaction with target proteins.
Superoxide dismutase (SOD) activity in CSF of patients was determined by electron spin resonance spectrometry using the spin trap method. Variation in SOD activity was found among patients. SOD activity in CSF of subjects increased with age and this was identified as Cu,Zn-SOD activity by electrophoresis. In addition, animal experiments showed that SOD activities were higher in mitochondrial and cytosol fractions of aged rats than in those of adult rats. This finding on aged rat brain validates the increase of SOD activity in aged human CSF.
A startlingly simple molecule unites neuroscience, physiology, and immunology, and revises scientists' understanding of how
cells communicate and defend themselves.
Concentrations of TBA-reactive substances (TBARS) were measured spectrophotometrically in homogenates of small samples of the brain (hypothalamus, parieto-occipital, sensori-motor and limbic cortex), heart, liver and adrenals of male August and Wistar rats; the former strain is more susceptible to emotional stress than the latter one. Forced isolation of the rats in the restraining plastic cages for 1 h increased the TBARS concentrations in the hypothalamus and liver in August rats only. TBARS accumulation in some tissues correlated with such indices of emotional stress as the changes in relative weight of thymus and adrenals. As regards the brain regions, after 1-hour emotional stress the TBARS levels were no longer different because of an increment in hypothalamic TBARS concentration. However, in control conditions the hypothalamus had significantly lower TBARS levels than any other brain structure both in Wistar and August rats.
Gastrodia elata Bl. (GE) and Uncaria rhynchophylla (Miq.) Jacks (UR) are two traditional Chinese medicinal herbal drugs, used for the treatment of convulsions and epilepsy. Their antioxidant effects in vivo and their free radical scavenging effects in vitro were investigated. Epileptogenic foci in the lateral brain of the rat were induced by the injection of ferric chloride into the lateral cortex. Both extracts significantly inhibited the increase in levels of lipid peroxide in the ipsilateral cortex, at all times observed. In addition, the two extracts also induced an early increase of activity of superoxide dismutase in the mitochondrial fraction of the ipsilateral cortex. In in vitro experiments, the two extracts exhibited significant dose-dependent scavenging effects on free radicals, using electron spin resonance spectroscopy. These results suggest that the proposed antiepileptic effects of GE and UR may be attributable to the antioxidant activity of the active components in these two medicinal herbs.
The real‐time kinetics of the release of ascorbyl free radicals in the coronary perfusate from isolated rat hearts submitted to an ischemia/reperfusion sequence has been achieved by continuous‐flow ESR using high‐speed acquisition techniques. Enhanced ESR detection of ascorbyl free radicals was obtained by addition of dimethyl sulfoxide (Me 2 SO), a strong cation chelator and oxidizing agent. A continuous‐flow device allowed a direct monitoring of the ascorbyl free radical and/or ascorbate leakage in coronary perfusate by observation of the ascorbyl radical doublet ( a H = 0.188 mT and g = 2.0054).
The results showed that ascorbyl free radical release occurred mainly during sequences of low‐flow ischemia (90 min) coupled or not with 30 min of zero‐flow ischemia followed by reperfusion (60 min). The kinetic profiles of ascorbyl‐free‐radical detection confirm in quantitative terms the expected correlation between the duration of the ischemic insult and the magnitude of ascorbate extracellular release upon reperfusion. There is indication that ascorbyl free radical depletion could be secondary to oxygen‐derived‐free‐radical‐induced cellular damage.
The amount of residual ascorbic acid was quantitated on myocardial tissue at the end of reperfusion using Me 2 SO as extracting solvent. Intense oxidation of ascorbate and chemical stabilization of the resulting free radical species provided by Me 2 SO allowed ESR measurement of a marked tissue ascorbate depletion related to the duration of ischemia.
Perfusion of superoxide dismutase during low‐flow ischemia and the first 10 min of reperfusion greatly inhibited both extracellular release and endogenous ascorbate depletion. These results suggest that the ascorbate redox system constitutes a major protective mechanism against free‐radical‐induced myocardial injury.
The proposed direct ESR detection of ascorbyl free radicals in the coronary perfusates or in tissue extracts does not require extensive chemical preparation and conditioning of effluent or tissue samples. It provides an interesting straightforward alternative to the evaluation of detrimental free radical processes affecting the myocardium during ischemia and reperfusion.
The reaction of metmyoglobin with equimolar concentrations of hydrogen peroxide has been studied using both electron spin resonance (e.s.r.) and optical spectroscopy. Using the former technique a strong anisotropic e.s.r. signal is observed, in the presence of the spin trap DMPO, which decays relatively rapidly. This previously unobserved signal, which is also observed on reaction of metmyoglobin with a number of other powerful oxidants (peracetic acid, 3-chloroperoxybenzoic acid, monoperoxyphthalic acid, iodosyl benzene, tBuOOH and cumene hydroperoxide) is assigned to a slowly-tumbling, metmyoglobin-derived, spin adduct. The parameters of this signal (aN 1.45, aH 0.83 mT) are consistent with the trapped radical having a heteroatom centre: this is believed to be oxygen. The concentration of this species is not affected by compounds such as 2-deoxyribose, mannitol and phenylalanine which are all efficient hydroxyl radical scavengers, demonstrating that the formation of this radical is not due to reaction of "free" HO. generated by breakdown of H2O2 by released iron ions. The concentration of this species is however decreased by desferal, ascorbate. Trolox C, salicylate and, to a lesser extent, linoleic acid; with the first three of these compounds further substrate-derived radicals are also observed. Examination of similar reaction systems (though in the absence of DMPO) by optical spectroscopy shows that the myoglobin (IV) species is formed and that this species behaves in a somewhat different manner with these added compounds. These results suggest that the radical trapped in the e.s.r. experiments is a myoglobin-derived species, probably a tyrosine peroxyl radical, arising from oxidative damage to the globin moiety. The diminution of both the e.s.r. signal of the spin adduct and the optical absorption of the myoglobin (IV) species in the presence of linoleic acid suggests that these myoglobin-derived species can initiate oxidative damage but that this process can be ameliorated by the presence of a number of water-soluble compounds such as ascorbate, Trolox C, desferal and salicylate.
Under certain circumstances, added antioxidants can protect tissues against reoxygenation injury after ischemia. Yet reperfusing blood carries many antioxidants with it. The implications of this "antioxidant paradox" are discussed.
The basic chemistry of the propagation of lipid peroxidation reactions has been known for years, but the mechanism of initiation of this process in biological membrane systems is still uncertain. Currently available assays for measuring peroxidation are reviewed--the more specific the assay used, the less peroxide is found in healthy human tissues and body fluids. Lipid peroxidation can arise as a consequence of tissue injury in many disease states and may sometimes contribute significantly to worsening the tissue injury.
This study investigated the relationship between lipid peroxidation, subsequent activation of antiox‐idative enzymes, and development of iron‐induced epilepsy in the rat. Epileptic foci were produced in rat cerebral cortex by intracortical injection of ferric chloride (FeCl 3 ). The epileptic foci were identified by electrocor‐ticography (ECoG). Epileptiform ECoG activity was shown to occur in the contralateral homotopic cerebral cortex as well. We measured levels of lipid peroxides and changes in the activities of the enzymes: superoxide dismutase (SOD), glutathione peroxidase (GP), glutathione reductase (GR), catalase (CA), and glucoses‐phosphate dehydrogenase (G6P) in the epileptogenic focus (both ipsilateral and contralateral) at days 3, 8, 15, and 23 after FeCI 3 injection. Biochemical estimations were made in subcellular fractions, and changes in the ipsilateral site were compared with those in the contralateral site. The results of this study showed that large increases in lipid peroxidation were associated with development and buildup of the ECoG epileptiform discharges. Lipid peroxides increased in the ipsilateral focus by –100% as compared with control. In the contralateral site, however, the increase in lipid peroxides was marginal only. The increase in lipid peroxidation was concomitant with development of the high level of epileptiform activity. The time course of changes in lipid peroxidation paralleled the time course of development and persistence of the epileptiform activity. Regarding changes in the enzyme activities accompanying development of iron epilepsy, the data showed that although SOD and G6P increased by ˜60% and GR increased by ˜40%, the increases in the enzyme GP and CA were much lower, <20%. Thus, comparatively less increase in CA and GP activities produces a deficiency of these two enzymes in the iron (ipsilateral) focus. Among the various biochemical disturbances that have been identified as involved in epileptogenesis, peroxidative injury resulting from lipid peroxidation in neural plasma membrane may be causally related to development of paroxysmal epileptiform activity in the iron focus. Since GP is an enzyme of major importance in detoxification of lipid peroxides in the brain, based on the results presented in this article, it appears reasonable to suggest that GP deficiency causes lipid peroxidation to increase tremendously during iron epileptogenesis.
RÉSUMÉ
Les mécanismes d'action des anttépileptiques efficaces pour le traitement des crises généralisées de type absences (antiabsences) restent méconnus. Les anti‐absences sont généralement efficaces pour les crises expérimentales induites par les pentylènetétrazol (PTZ) et le méthyl‐6,7‐diméthoxyl‐4‐éthyl‐β‐carboline‐3‐carboxylate (DMCM), médicaments qui réduisent l'inhibition GABAergique. On a done suggéré que les anti‐absences pouvaient augmenter l'inhibition GABAergique. Les auteurs ont étudié les effets de plusieurs antiépileptiques sur les réponses GABA enregistrées au niveau de neurones médullaires poussant sur une culture cellulaire primaire dissociée. 4 anti‐absences ont été Studies: l'gthosuximide (ESM), la diméthadione (DMD), le valproate (VPA) et de diazépam (DZP). Deux antiéileptiques expérimentaux, le CGS 9896 et le ZK 91296, dont l'activité anticonvulsivante sur les crises induites par PZT et DMCM a été prouvée, ont aussi étéétudiés. Les auteurs ont évalué aussi les effets des anti‐absences et des drogues exéri‐mentales sur l'inhibition de la réponse GABA induite par PTZ et par DMCM. PTZ et DMCM nt entraîné une réduction réversible et dose‐dépendante des réponses GABA. Le PTZ a inhibe to‐talement les reponses GABA à 10 m M (IC 50 de 1.1 m M ) alors que l'inhibition par la DMCM atteint une valeur plateau de 39%à 1 μ.M (IC 50 de 33 m M ). L'ESM (1200 μ M ), la DMD (6 m M ), le VPA (200 μ . M) , le CGS 9896 (2 μ. M ) et le ZK 912% (2 μ M ) n'ont pas modifie les reponses GABA. Le DZP augmente les réponses GABA de façon concentration‐dépendante. L'inhibition des réponses GABA produite par le PTZ à 1 m M n'a pas été modifyée par l'ESM (600 μ. M ), la DMD (6 m M ), le CGS 9896 (1 μ M) ou le ZK 912% (1 μ. M ). L'application simultanée de VPA (200 μ .M) et de PTZ (1 m M ) a légèrement augmenté l'effet du PTZ. Le DZP (<10 n M ), en revanche, a négativé l'induction des réponses GABA entraînée par le PTZ. L'inhibition des réponses GABA entraînée par le DMCM (250 n M ) n'a pas été modifyée par l'ESM (600 μ. M ), la DMD (2 m M ) ou le VPA (200 μ M ). Cependant, le CGS 98% (2 μ, M ) et le ZK 91296 (2 μ M )ont antagonisé l'effet du DMCM. Le DZP (<10 n M ) a significativement inversé l'inhibition des réponses GABA entraînée par le DMCM. L'absence d'effets du VPA, de l'ESM et de la DMD sur les réponses GABA post‐synaptiques suggère qu'une augmentation directe de l'activité GABA post‐synaptique n'est pas un mécanisme d'action commun des médications anti‐absences. Le DZP, le CGS 98% et le ZK 91296 ont tous annuié l'effet inhibiteur des réponses GABA du DMCM, mais pas celui du PTZ, ce qui suggère que ces antiépileptiques ont inhibe les crises en agissant au niveau des récepteurs aux benzodiazépines. Cependant, comme seul le DZP augmente les réponses GABA, le mécanisme d'action du CGS 98% et du ZK 912% dans l'inhibition des crises au PTZ n'appa‐raît clairement.
RESUMEN
En este estudio se ha investigado, en la rata, la relaciioAn entre la peroxidación lipídica, la subsiguiente activación de las enzimás anti‐oxidativas y el desarrollo de epilepsyía inducida por el hierro. Los focos epilépticos se produjeron en la corteza cerebral de la rata mediante la inyección intracortical de cloruro férrico (C13 Fe). Los focos epilépticos se identificaron mediante electrocorticografía (ECoG). La actividad epileptiforme en la ECoG se observó tambien en la corteza cerebral contralateral homo‐tópica. En los focos epileptogénicos (homolateral y contralateral) nemos medido, en los dias 3, 8, 15, y 23 después de la inyección de C13 Fe, los niveles de las lipido‐peroxidasas y los cambios en la actividad de las enzimás siguientes: superóxido dismutasa, glutatión‐peroxidasa, glutatión‐reductasa, catalasa y glucosa‐6‐fosfatasa dehidrogenasa. Las estimaciones bioquími‐cas se determinaron en fracciones subcelulares y los cambios en las zonas homolaterales se compararon con las contralaterales. Los resultados de este estudio muestran que los amplios incre‐mentos en la peroxidación de los lípidos se asociaron a un desarrollo e incremento de las descargas epileptiformes en el ECoG. La peroxidación de los lipidos se incremento en el foco homolateral en un 100% comparándola con el control. En la zona contralateral, sin embargo, se observó solamente un incremento marginal de esta peroxidación. El incremento de la peroxidación file congruente con el desarrollo de un alto nivel de actividad epileptiforme. El curso temporal de la peroxidación de los lípidos siguió un proceso paralelo al curso temporal del desarrollo y persistencia de la actividad epileptiforme. En relación con los cambios de las actividades enzimáticas que acompañan al desarrollo de la epilepsia inducida por el hierro, esta información muestra que, a pesar de que la superóxido‐dismutasa y la glu‐cosa‐6‐fosfato dehidrogenasa se incrementaron en un 60% y la glutatidn‐ieductasa en un 40%, los incrementos de las enzimás glutatión‐peroxidasa y catalasa fueron mucho menores, menos del 20%. Asf pues, son necesarios incrementos comparativa‐mente menos importantes de las actividades de catalasa y gluta‐tión‐peroxidasa para producir un déficit de estas dos enzimás en los focos homolaterales producidos por el hierro. Entre las diversas alteraciones bioquímicas que se han identificado como participantes en la epileptogénesis, la lesión peroxidativa que resulta de la peroxidación de los Upidos en la membrana plasmátics de las neuronas puede estar relacionada causalmente al desarrollo de actividad epileptiforme paroxfstica en el foco pro‐ducido por el hierro. Puesto que la glutatión‐peróxidasa es una enzima de gran importancia en la detoxificación de los peróxidos lipídicos en el cerebro, parece razonable sugerir que el déficit de glutatión‐peroxidasa causa un enorme incremento de la peroxidación de los Upidos en la epileptogénesis producia por el hierro.
ZUSAMMENFASSUNG
In dieser Arbeit wurde die Beziehung zwischen Lipidperoxi‐dation, damit verbundener Aktivierung von antioxydativen En‐zymen und die Entwicklung von Eisen induzierter Epilepsie bei der Ratte untersucht. Die epileptischen Foci wurden durch in‐tracorticale Injektion von Eisenchlorid (FeCB) im Rattencortex erzeugt. Sie wurden durch Elektrocorticographie (ECOG) iden‐tifiziert. Im kontralateralen homotopen cerebralen Cortex wurde ebenso das Auftreten von epileptiformer ECOG Aktivität ge‐funden. Wir bestimmten die Lipidperoxydase‐Spiegel und Veränderungen in den Enzymaktivitäten von Superoxyd‐Dismutase, Glutathion‐Peroxydase, Glutathion‐Reduktase, Katalase und Glukose‐6‐Phosphat‐Dehydrogenase im epilepto‐genen Fokus sowohl ipsi‐ als auch kontralateral an den Tagen 3, 8, 15 und 23 nach der FeCe3‐Injektion. In den subzellulären Fraktionen wurden biochemische Schätzungen gemacht und Verändeningen im ipsilateralen Cortex wurden mit denen der kontralateralen Seite verglichen. Die Ergebnisse dieser Untersu‐chungen zeigen, daß große Steigerungen der Lipidperoxydation mit der Entwicklung von cortikalen epileptiformen Entladungen im EEG assoziiert sind. Lipidperoxyde stiegen im ipsilateralen Fokus um 100% im Vergleich zu Kontrollen an. Auf der kontralateralen Seite war dagegen nur ein marginaler Zuwachs an Lipidperoxyden festzustellen. Der Anstieg der Lipidperoxydation ging mit der Entwicklung von starker epileptiformer Aktivitat einher. Der Zeitverlauf in den Änderungen der Lipidperoxydation verlief parallel zum Zeitverlauf der Entwicklung und dem Fortbestehen von epileptiformer Aktivität. In Bezug auf Veränderungen der Enzymaktivitäten, die die Entwicklung der Eisenepilepsie begleitétén, zeigen die Daten, daß bei einem Anstieg von SuperoxydDismutase und Glukose‐6‐Phosphat‐Dehydrogenase um 60% und von Glutathion Reduktase um 40% der Anstieg von Glutathion‐Peroxydase und Katalase geringer, weniger als 20%, war. Das heifit ein verhältnismäßig geringer Anstieg von Katalase und Glutathion Peroxydase Aktivität führte zu einem Mangel der beiden Enzyme beim ipsilateralen Eisenfokus. Unter den verschiedenen biochemischen Störungen, die bei der Epileptogenese involviert sind, dürfte eine peroxydative Stöning der Lipidperoxydation in der neuronalen Plas‐mamembran ursächlich zur Entwicklung von epileptiformer Aktivitat im Eisenfokus in Beziehung stehen. Da Glutathion‐Peroxydase ein wichtiges Enzym in der Entgiftung von Lipidperoxyden im Gehirn ist, scheint aufgrund der in dieser Arbeit geschilderten Resultate die Schlußfolgerung gerechtfer‐tigt, daß ein Glutathion‐Peroxydase‐Mangel zu einer starken Er‐höhung von Lipidperoxydation bei der Eisen‐induzierten Epileptogenese führt.
Hydrogen peroxide and organic hydroperoxides react with haemoglobin to release iron which can be complexed to apotransferrin, bleomycin and desferrioxamine. This released iron promotes deoxyribose degradation by a Fenton reaction, DNA degradation in the presence of bleomycin and stimulates lipid peroxidation. It is likely that iron released from haemoglobin is the true generator of hydroxyl radicals in the Fenton reaction. Hydroxyl radical Lipid peroxidation Transferrin iron binding Heme-protein iron release Hemoglobin Fenton catalyst Desferrioxamine Bleomycin-detectable iron.
We propose that an important function of superoxide dismutase is to prevent radical-mediated chain oxidation of GSH, thereby enabling GSH to act physiologically as a free radical scavenger without concomitant oxidative stress to the cell. Through this action, the combination of SOD and GSH plays a significant role in intracellular antioxidant defence
Activity of physiological antioxidant system was decreased while lipid peroxidation was increased in blood, brain, paradontium and submaxillary salivary gland under conditions of acute pain-emotional stress, deficiency of antioxidants and of their combined effect. Deficiency of antioxidants caused the most pronounced stress-dependent activation of lipid peroxidation in parodontium; less distinct reactions were observed in brain and submaxillary salivary gland.
The influence of emotional painful stress (EPS) and dimethyl sulfoxide (DMSO) treatment on ceruloplasmin-transferrin (Cp-Tr) antioxidant system and superoxide dismutase-like activity (SODLA) of the rat serum was studied. No changes in Cp-Tr and SODLA were observed in EPS. On the contrary, DMSO treatment was followed by a decrease in Cp-Tr activity and an increase in SODLA. It is suggested that Cp-Tr and SODLA systems are two interacting antioxidant systems of the serum.
Incubation of horse-heart oxymyoglobin or metmyoglobin with excess H2O2 causes formation of myoglobin(IV), followed by haem degradation. At the time when haem degradation is observed, hydroxyl radicals (.OH) can be detected in the reaction mixture by their ability to degrade the sugar deoxyribose. Detection of hydroxyl radicals can be decreased by transferrin or by .OH scavengers (mannitol, arginine, phenylalanine) but not by urea. Neither transferrin nor any of these scavengers inhibit the haem degradation. It is concluded that intact oxymyoglobin or metmyoglobin molecules do not react with H2O2 to form .OH detectable by deoxyribose, but that H2O2 eventually leads to release of iron ions from the proteins. These released iron ions can react to form .OH outside the protein or close to its surface. Salicylate and the iron chelator desferrioxamine stabilize myoglobin and prevent haem degradation. The biological importance of .OH generated using iron ions released from myoglobin by H2O2 is discussed in relation to myocardial reoxygenation injury.
There is a growing body of evidence for the role of free radicals in mediating myocardial tissue injury during myocardial ischemia and in particular during the phase of myocardial reoxygenation. Associated with myocardial ischemia and reperfusion is the generation of oxygen-derived free radicals from a variety of sources that include the mitochondrial electron transport chain; the biosynthesis of prostaglandins; the enzyme xanthine oxidase; and circulating elements in the blood, with the polymorphonuclear neutrophil assuming a primary focus of attention. Experimental studies have shown that free radical scavengers (e.g., N-[2-mercaptopropionyl]glycine) and enzymes that scavenge or degrade reactive species of oxygen (superoxide dismutase or catalase) can reduce the mass of myocardial tissue that undergoes irreversible injury. Additionally allopurinol, which inhibits the enzyme xanthine oxidase, reduces ultimate infarct size, putatively by reducing the xanthine oxidase generation of superoxide anion. Neutrophils that enter the ischemically injured myocardium under the influence of chemotactic attraction and activation of the complement system generate and release highly reactive and cytotoxic oxygen derivatives that are destructive to the vascular endothelium and to the cardiac myocytes. Studies have documented that neutrophil depletion or suppression of neutrophil function (ibuprofen, nafazatrom, BW 755C, or more recently with prostacyclin or iloprost) results in a significant salvage of myocardial tissue that is subjected to a period of regional ischemia followed by reperfusion. Our current understanding of the events associated with myocardial ischemia suggests that within the ischemic myocardial region or area at risk, there is a population of cells that are reversibly injured and that reperfusion within a specified period (less than 3 hours) of time is capable of restoring the majority of the jeopardized cells to a normal status, but that the act of reperfusion itself will lead to the sudden demise of a fraction of the cells because of the cytotoxic effects of reactive species of oxygen derived from one or more of the sources indicated above. The efforts to minimize the amount of tissue that undergoes cell death as a result of myocardial ischemia demand that early reperfusion be established. However, the reintroduction of molecular oxygen and the circulating elements of the blood will be associated with an "explosive" and self-limited destruction of some of the myocardial cells in the area at risk.(ABSTRACT TRUNCATED AT 400 WORDS)
The ability of oxyhaemoglobin and methaemoglobin to generate hydroxyl radicals (OH.) from H2O2 has been investigated using deoxyribose and phenylalanine as 'detector molecules' for OH.. An excess of H2O2 degrades methaemoglobin, releasing iron ions that react with H2O2 to form a species that appears to be OH.. Oxyhaemoglobin reacts with low concentrations of H2O2 to form a 'reactive species' that degrades deoxyribose but does not hydroxylate phenylalanine. This 'reactive species' is less amenable to scavenging by certain scavengers (salicylate, phenylalanine, arginine) than is OH., but it appears more reactive than OH. is to others (Hepes, urea). The ability of haemoglobin to generate not only this 'reactive species', but also OH. in the presence of H2O2 may account for the damaging effects of free haemoglobin in the brain, the eye, and at sites of inflammation.
The interaction of glutathione (GSH) with ascorbic acid and dehydroascorbic acid was examined in in-vitro experiments in order to examine the role of GSH in protecting against the autoxidation of ascorbic acid and in regenerating ascorbic acid by reaction with dehydroascorbic acid. If a buffered solution (pH 7.4) containing 1.0 mM ascorbic acid was incubated at 37 degrees C, there was a rapid loss of ascorbic acid in the presence of oxygen. When GSH was added to this solution, ascorbic acid did not disappear. Maximum protection against ascorbic acid autoxidation was achieved with as little as 0.1 mM GSH. Cupric ions (0.01 mM) greatly accelerated the rate of autoxidation of ascorbic acid, an effect that was inhibited by 0.1 mM GSH. Other experiments showed that GSH complexes with cupric ions, resulting in in a lowering of the amount of GSH in solution as measured in GSH standard curves. These results suggest that the inhibition of ascorbic acid autoxidation by GSH involves complexation with cupric ions that catalyze the reaction. When ascorbic acid was allowed to autoxidize at 37 degrees C the subsequent addition of GSH (up to 10 mM) did not lead to the regeneration of ascorbic acid. This failure to detect a direct reaction between GSH and the dehydroascorbic acid formed by oxidation of ascorbic acid under this condition was presumably due to the rapid hydrolysis of dehydroascorbic acid. When conditions were chosen, i.e., low temperature, that promote stability of dehydroascorbic acid, the direct reaction between GSH and dehydroascorbic acid to form ascorbic acid was readily detected. The marked instability of dehydroascorbic acid at 37 degrees C raises questions regarding the efficiency of the redox couple between GSH and dehydroascorbic acid in maintaining the concentration of ascorbic acid in mammalian cells exposed to an oxidative challenge.
One hour of regional ischemia significantly increases the permeability of intestinal capillaries. The role of local humoral agents in the genesis of an increased capillary permeability in the ischemic bowel was assessed using specific antagonists to substances commonly believed to be involved in the pathogenesis of ischemic states. Capillary permeability estimates in autoperfused segments of cat ileum were derived from the relationship between lymph-to-plasma protein concentration ratio and lymph flow. Pretreatment of the ileal segments with either benadryl + cimetidine, indomethacin, or methylprednisolone did not significantly alter the permeability increase induced by regional ischemia. Pretreatment with superoxide dismutase (SOD), a superoxide radical scavenging enzyme, significantly attenuated the capillary permeability change induced by regional ischemia. Intravenous E. coli endotoxin administration in normotensive preparations increased intestinal capillary permeability; however, lethal doses of the endotoxin were required. The results of this study indicate that superoxide radicals are primarily responsible for the increased capillary permeability in the ischemic bowel.
During primate evolution, a major factor in lengthening life-span and decreasing age-specific cancer rates may have been improved protective mechanisms against oxygen radicals. We propose that one of these protective systems is plasma uric acid, the level of which increased markedly during primate evolution as a consequence of a series of mutations. Uric acid is a powerful antioxidant and is a scavenger of singlet oxygen and radicals. We show that, at physiological concentrations, urate reduces the oxo-heme oxidant formed by peroxide reaction with hemoglobin, protects erythrocyte ghosts against lipid peroxidation, and protects erythrocytes from peroxidative damage leading to lysis. Urate is about as effective an antioxidant as ascorbate in these experiments. Urate is much more easily oxidized than deoxynucleosides by singlet oxygen and is destroyed by hydroxyl radicals at a comparable rate. The plasma urate levels in humans (about 300 microM) is considerably higher than the ascorbate level, making it one of the major antioxidants in humans. Previous work on urate reported in the literature supports our experiments and interpretations, although the findings were not discussed in a physiological context.
1. The thiobarbituric acid (TBA) reaction, widely applied to the detection of autoxidation in polyunsaturated fatty acids, can be used to measure free-radical damage to amino acids, carbohydrates and nucleic acids. 2. In all of these systems malondialdehyde (MDA) is predominately formed from intermediate precursor molecules which break down during the acid-heating stage of the TBA test. 3. The acid reagent used to bring about these decompositions appears to be critical.
The exposure of DNA to H2O2 in the presence of Cu(II) and a reducing agent is known to result in the induction of a variety of oxidative lesions, including DNA strand breaks and base modifications. Since the reducing agent glutathione occurs in cell nuclei at relatively high concentrations, and copper exists in nuclei associated with chromatin, the present study was undertaken to evaluate the ability of GSH to promote copper-mediated free radical damage to DNA. When compared with ascorbate, GSH was found to be inefficient in the promotion of damage to DNA. Parallel ESR spin trapping measurements indicated that GSH inhibits free radical formation by copper ions in the presence of H2O2, ascorbate, and DNA. The protective effect of GSH is attributed to its stabilization of copper in the +1 oxidation state, thereby compromising its ability to participate in free radical generating reactions. Consequently, it is suggested that the GSH in cell nuclei serves to prevent, rather than promote, copper-dependent damage to DNA. In contrast, in the presence of 1,10-phenanthroline, GSH stimulated free radical formation and DNA damage. This is attributed to the failure of GSH to remove copper(I) from 1,10-phenanthroline. Therefore, under these conditions, GSH serves primarily to redox cycle the reactive 1,10-phenanthroline-copper complex.
Free radicals vary widely in their thermodynamic properties, ranging from very oxidizing to very reducing. These thermodynamic properties can be used to predict a pecking order, or hierarchy, for free radical reactions. Using one-electron reduction potentials, the predicted pecking order is in agreement with experimentally observed free radical electron (hydrogen atom) transfer reactions. These potentials are also in agreement with experimental data that suggest that vitamin E, the primary lipid soluble small molecule antioxidant, and vitamin C, the terminal water soluble small molecule antioxidant, cooperate to protect lipids and lipid structures against peroxidation. Although vitamin E is located in membranes and vitamin C is located in aqueous phases, vitamin C is able to recycle vitamin E; i.e., vitamin C repairs the tocopheroxyl (chromanoxyl) radical of vitamin E, thereby permitting vitamin E to function again as a free radical chain-breaking antioxidant. This review discusses: (i) the thermodynamics of free radical reactions that are of interest to the health sciences; (ii) the fundamental thermodynamic and kinetic properties that are associated with chain-breaking antioxidants; (iii) the unique interfacial nature of the apparent reaction of the tocopherol free radical (vitamin E radical) and vitamin C; and (iv) presents a hierarchy, or pecking order, for free radical electron (hydrogen atom) transfer reactions.
Using a split-litter distribution, half of a sample of albino rats were handled daily for 10-minute periods, starting immediately after weaning and continuing for the next 21 days. Results of 4 experiments indicated that gentling influenced (1) increase in body weight and skeletal length, (2) increase of activity in an open field and (3) decrease in organic damage following immobilization stress. Adrenal glands of non-gentled animals were significantly heavier. (PsycINFO Database Record (c) 2006 APA, all rights reserved).
Uric acid provides an antioxidant defense in humans against oxidant- and radical-caused aging and cancer: a hypothesis
- Ames
Glutathione deficiency decreases tissue ascorbate levels in newborn rats: ascorbate spares glutathione and protects
- Mortensson
Reduced glutathione in combination with superoxide dismutase as an important biological antioxidant defense mechanism
- Munday