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Representative cerebellar Purkinje cells stained with the Golgi-Cox procedure. (A), (C) control animals at 22 and 52 postnatal days, respectively; (B), (D) betamethasonetreated animals at 22 and 52 postnatal days, respectively. Sale bar is 20 µm.
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In the current study, we analyzed the impact of antenatal betamethasone on macroscopic cerebellar development, Purkinje cell morphology and the expression of the neuroprotective protein calbindin-D28k. Pregnant rats (Sprague-Dawley) were randomly divided into two experimental groups: control (CONT) and betamethasone-treated (BET). At gestational da...
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... In humans, a significant reduction in grey matter within multiple brain regions, notably the prefrontal cortex, cerebral cortex, and cerebellum, was associated with midgestation self-reported anxiety [100,101]. Cerebellar weight and volume in rat offspring were also sensitive to a single exposure to a synthetic glucocorticoid, betamethasone, in late gestation [102]. The single exposure was also associated with anxiety-related behavior and increased expression of calbindin-D28K, a neuroprotective protein whose expression is associated with levels of glucocorticoids. ...
For decades, the Barker hypothesis and thrifty phenotype hypothesis have driven researchers to explore the development of metabolic syndrome through fetal programming. In this short review, we provide peer-reviewed support for the fetal programming of neural genetic activity and behavior in multiple neural regions: the prefrontal cortex, the cerebral cortex, the hippocampus, the cerebellum, and the hypothalamic–pituitary–adrenal axis. We also introduce ionizing radiation as a purported indirect driver of phenotypical changes. The predisposition of brain and behavioral phenotypes after gestational exposure to stressors can lead to aversive and harmful outcomes, rather than protective adaptations.
... Synthetic glucocorticoid (SGC) administration is considered a type of prenatal stress (PS) because it causes impaired foetal development and vulnerability to different diseases established by foetal programming, which are manifested later in adolescence or adult life [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Moreover, exposure to SGCs in utero during the last quarter of gestation is a pharmacological therapy widely used in the obstetric clinic to accelerate the maturation of lung tissue and subsequently increase the survival of the foetus in cases of premature birth and their use (a single course of betamethasone or dexamethasone) to mature the foetal lung in pregnancies likely to deliver before 34 weeks is recommended [3,6,8,11,14,[15][16][17]. ...
... We systematically studied the effect of the prenatal administration of an SGC, betamethasone (BET), on some relevant aspects of neurodevelopment using Sprague-Dawley rats as an animal model [6,7,9,10,12,14,36]. Among the most relevant findings, we found that the prenatal administration of BET alters the dendritic growth of Purkinje cells [7]. ...
... We systematically studied the effect of the prenatal administration of an SGC, betamethasone (BET), on some relevant aspects of neurodevelopment using Sprague-Dawley rats as an animal model [6,7,9,10,12,14,36]. Among the most relevant findings, we found that the prenatal administration of BET alters the dendritic growth of Purkinje cells [7]. However, the molecular mechanisms that underlie these alterations have not been fully described. ...
During prenatal life, exposure to synthetic glucocorticoids (SGCs) can alter normal foetal development, resulting in disease later in life. Previously, we have shown alterations in the dendritic cytoarchitecture of Purkinje cells in adolescent rat progeny prenatally exposed to glucocorticoids. However, the molecular mechanisms underlying these alterations remain unclear. A possible molecular candidate whose deregulation may underlie these changes is the glucocorticoid receptor (GR) and neurotrophin 3/ tropomyosin receptor kinase C, neurotrophic complex (NT-3/TrkC), which specifically modulates the development of the neuronal connections in the cerebellar vermis. To date, no evidence has shown that the cerebellar expression levels of this neurotrophic complex are affected by exposure to a synthetic glucocorticoid in utero. Therefore, the first objective of this investigation was to evaluate the expression of GR, NT-3 and TrkC in the cerebellar vermis using immunohistochemistry and western blot techniques by evaluating the progeny during the postnatal stage equivalent to adolescence (postnatal Day 52). Additionally, we evaluated anxiety-like behaviours in progeny using the elevated plus maze and the marble burying test. In addition, an environmental enrichment (EE) can increase the expression of some neurotrophins and has anxiolytic power. Therefore, we wanted to assess whether an EE reversed the long-term alterations induced by prenatal betamethasone exposure. The major findings of this study were as follows: i) prenatal betamethasone (BET) administration decreases GR, NT-3 and TrkC expression in the cerebellar vermis ii) prenatal BET administration decreases GR expression in the cerebellar hemispheres and iii) enhances the anxiety-like behaviours in the same progeny, and iv) exposure to an EE reverses the reduced expression of GR, NT-3 and TrkC in the cerebellar vermis and v) decreases anxiety-like behaviours. In conclusion, an enriched environment applied 18 days post-weaning was able to restabilize GR, NT-3 and TrkC expression levels and reverse anxious behaviours observed in adolescent rats prenatally exposed to betamethasone.
... 6 In addition, glucocorticoids inhibit hormones critical for fetal growth. 7 In animal models, exposure to ACS has been shown to result in detrimental long-term neurocognitive and neurobehavioral effects, 8 including anxiety-like behavior, [9][10][11][12] delayed motor development, 13,14 and impaired spatial memory. 15,16 In a systematic review of animal fetuses, ACS exposure most commonly altered glucocorticoid receptors in the hippocampus and hypothalamus with coincident neurocognitive sequelae. ...
The objective of this study was to synthesize the body of knowledge on the association between ACS exposure for risk of preterm birth and brain development in infants ultimately born late preterm and term. Three databases and eight conference proceedings were systematically searched (1972–2021). Selection criteria included ACS administration for risk of preterm delivery, cohort of late preterm and term infants, and assessment of brain development. Data on study characteristics, ACS administration, and neurological outcomes were extracted and qualitatively synthesized according to themes. Neurological outcomes of the included studies (n = 27) were grouped into four themes. The most common adverse outcomes were reduced neonatal head circumference, structural cortical differences on MRI, increased prevalence of psychiatric problems, and increased risk of neurodevelopmental delays in ACS-exposed late preterm and term infants. Our scoping review demonstrated that ACS exposure for risk of preterm delivery may have important neurological implications in infants ultimately born late preterm and term. Given that the existing research is at serious risk for bias, further research that accounts for confounders such as preterm labor, maternal stress, and the number of ACS courses is needed to better establish the long-term neurological effects of ACS on late preterm and term infants. Due to the difficulty in predicting preterm birth, approximately 40% of fetuses exposed to antenatal corticosteroids (ACS) are born at term (≥37 weeks’ gestation).This scoping review summarizes the knowledge on the association between ACS exposure for risk of preterm birth and brain development in late preterm and term infants.The majority of studies reported that ACS exposure was associated with adverse brain development outcomes across various domains, such as reduced neonatal head circumference, cortical differences on MRI, and increased prevalence of psychiatric problems and neurodevelopmental delays in late preterm and term infants. Due to the difficulty in predicting preterm birth, approximately 40% of fetuses exposed to antenatal corticosteroids (ACS) are born at term (≥37 weeks’ gestation). This scoping review summarizes the knowledge on the association between ACS exposure for risk of preterm birth and brain development in late preterm and term infants. The majority of studies reported that ACS exposure was associated with adverse brain development outcomes across various domains, such as reduced neonatal head circumference, cortical differences on MRI, and increased prevalence of psychiatric problems and neurodevelopmental delays in late preterm and term infants.
... Calbindin expression is used as a specifi c marker for identifying Purkinje cells in the cerebellum [6]. Overexpression of calbindin D28K protein in cerebellar cortex Purkinje cells may play a role in neuroprotection [7]. However, the distribution pattern of this protein in the cerebral cortex and cerebellum in rats in normal conditions has received insuffi cient study [3]. ...
Objective. To carry out an immunohistochemical assessment of the distribution of calbindin D28K in cerebral cortex (parietal and frontal) and cerebellum neurons in rats.Materials and methods. Experiments were performed on 18 mongrel white male rats weighing 200–250 g. Fragments of the frontal and parietal cortex and cerebellar cortex were collected. Paraffi n sections were processed using primary polyclonal antibodies to detect calbindin D28K immunoreactivity.Results. In layer II of the frontal and parietal cortex, most neurons were moderately immunopositive, while layers III, V, and VI contained occasional neurons with high calbindin immunoreactivity. Individual nerve fibers, mainly the dendrites of pyramidal neurons, were clearly seen. Some of these showed a distinctive staining pattern: immunopositive parts alternated with immunonegative parts. In the cerebellar cortex, the bodies and dendritic branches of Purkinje cells were well stained. A significant proportion of neurons in the granular layer were moderately immunopositive, and included some afferent nerve fibers running from the white matter.Conclusions. Calbindin immunoreactivity in cerebral cortex structures in normal rats varied significantly and could be related both to the type of neuron and their functional state.
... [28][29][30] Furthermore, only 10.9% (7/64) reported on the brain weight or volume at the time of harvesting wherein 57.1% (4/7) reported a decrease of brain weight after the exposure of ACS. 17,[30][31][32] Outcome assessment Neuropathology was the commonest outcome reported, either alone (28.1%, 18/64) Table 3. ...
... 66,67 Given this wide spectrum of regulatory roles, it is apparent that it will have a profound impact in postnatal and adult life. In rats, prenatal DM exposure resulted in more anxiety-like behavior, 22,31,45 sex-specific alterations in motor activity and sexual behavior, 15,59 and impaired spatial memory. 17,20 While in mice, maternal administration of ACS resulted in delayed development and impaired motoric function in the offspring. ...
... 72 From this review, both BM and DM resulted in longterm sequelae, with no clear benefit of one over another. As previously stated, most investigations used DM and mostly multiple dosing or courses, but even low dose or single courses of BM 28,30,31,47,50,73 and DM 32,48,49,55 resulted in clear neuropathological and neurobehavioral deficits. This systematic review and the assimilated research have limitations mostly due to the administration regimes chosen, the lack of stringent methodological approach, and non-standardized reporting. ...
Antenatal corticosteroids (ACSs) are recommended to all women at risk for preterm delivery; currently, there is controversy about the subsequent long-term neurocognitive sequelae. This systematic review summarizes the long-term neurodevelopmental outcomes after ACS therapy in animal models.
An electronic search strategy incorporating MeSH and keywords was performed using all known literature databases and in accordance with PRISMA guidance (PROSPERO CRD42019119663).
Of the 669 studies identified, eventually 64 were included. The majority of studies utilized dexamethasone at relative high dosages and primarily involved rodents. There was a high risk of bias, mostly due to lack of randomization, allocation concealment, and blinding. The main outcomes reported on was neuropathological, particularly glucocorticoid receptor expression and neuron densities, and neurobehavior. Overall there was an upregulation of glucocorticoid receptors with lower neuron densities and a dysregulation of the dopaminergic and serotonergic systems. This coincided with various adverse neurobehavioral outcomes.
In animal models, ACSs consistently lead to deleterious long-term neurocognitive effects. This may be due to the specific agents, i.e., dexamethasone, or the repetitive/higher total dosing used. ACS administration varied significantly between studies and there was a high risk of bias. Future research should be standardized in well-characterized models.
... Betamethasone (BM), a synthetic glucocorticoid, is considered the glucocorticoid of choice for this antenatal treatment (Alexander et al., 2016;Lindsley et al., 2015) being used for pregnant women between 24 and 34 weeks of gestation ( Jobe & Soll, 2004;Rayburn et al., 1997;Wapner, 2013), promoting fetal lung maturation and thus reducing the incidence of respiratory distress syndrome, neonatal mortality and morbidity (Gyamfi-Bannerman et al., 2016;Lindsley et al., 2015). However, the prenatal exposure to BM demonstrated several systemic long-term deleterious effects on offspring in different experimental protocols (Alexander et al., 2016;Belanoff et al., 2001;Bertram & Hanson, 2002;Pascual et al., 2014;Su et al., 2015). ...
Betamethasone is the drug of choice for antenatal treatment, promoting fetal lung maturation and decreasing mortality. Previous studies in rats reported male programming and alteration in sperm parameters and sexual behavior following intrauterine betamethasone exposure. The impact on the female reproductive development is not known. In this study, rat female offspring was assessed for sexual development, morphophysiology of the reproductive tract and fertility after maternal exposure to 0.1 mg kg−1 of betamethasone or vehicle on gestational days 12, 13, 18 and 19. The treatment promoted reduction of litter weight on postnatal day 1, morphological masculinization in females, delay in the age of puberty onset, reduction in estrus number, increase in estrous cycle length and increase in luteinizing hormone serum levels and uterus weight. The females from the betamethasone group showed an increase of myometrial uterine area and decrease in endometrial uterine area. These animals also performed less lordosis during the sexual behavior test and showed impaired reproductive performance. The uterus showed higher contraction in the treated group as shown by a pharmacological assay. In conclusion, prenatal betamethasone exposure in rats promoted female masculinization, altered sexual development and reproductive parameters. Copyright
... In our laboratory, we have systematically studied the effect of controlled prenatal synthetic GC (sGC) administration (betamethasone, BET) to the mother on behavioral and neuronal development in the offspring. We have observed that administering BET to pregnant rats at a therapeutic dose equivalent to that administered to women who are at risk of preterm delivery produces a significant decrease in dendritic arborization in both dentate granule and cerebellar Purkinje cells (9,10). However, it is unknown whether similar neuronal changes to pyramidal cortical cells occur during the early and late postnatal periods. ...
... For example, dentate granule cells of adolescent rats (P52) treated with prenatal BET (G20; 0.17 mg/kg) showed a significant reduction (-35%) in total dendritic length compared with age-matched controls (9). A similar reduction in dendritic domain (-39%) has been observed in cerebellar Purkinje cells at P52 in offspring treated antenatally with BET (10). In both studies, the neuronal changes were related to significant impairments in spatial memory tasks along with anxiety-like behaviors. ...
Previous animal studies have indicated that excessive prenatal circulating glucocorticoid (GC) levels induced by the antenatal administration of synthetic GC (sGC) significantly alter neuronal development in the cerebellar and hippocampal neurons of the offspring. However, it is unknown whether antenatal sGC administration results in long-term neocortical pyramidal cell impairment. In the current study, we examined whether an equivalent therapeutic dose of antenatal betamethasone phosphate (BET) in pregnant rats alters the Golgi-stained basilar dendritic length and histochemical expression of dendritic microtubule-associated protein 2 (MAP2) of neocortical pyramidal cells in infant, adolescent, and young adult offspring. The results obtained showed that in utero BET exposure resulted in a significant reduction in the basilar dendritic length per neuron and a transient reduction in histochemical MAP2 immunoreactivity. Consistent with previous hippocampal and cerebellar data, the present findings suggest that prenatal BET administration alters the dendritic growth of cerebrocortical pyramidal cells.
... This increased cerebellar vulnerability is most likely related to the fact that the mammalian cerebellar cortex expresses a remarkable density of glucocorticoid receptors, even exceeding that of the hippocampus or cerebral cortex [5,6], together with the fact that Purkinje cell dendritogenesis is rapid during the perinatal period [7,8]. Consistent with these data, in the present authors' laboratory, they have recently observed that the prenatal administration of betamethasone in equivalent therapeutic doses and during a similar ontogenetic stage (gestational day 20) [9,10] produced a significant alteration in the development of cerebellar Purkinje cells associated with an increase in the calcium sequestering protein calbindin-D28k [11]. It has also been reported that cerebellar Purkinje cell dendritic maturation is related to the expression of type 1 metabotropic glutamate receptors (mGluR1) present in the dendritic membrane. ...
... Because the direct administration of antenatal synthetic GCs in experimental animals at G20 produces a significant Purkinje cell developmental delay as shown in Golgi-Coxstained Purkinje cells [11], the present authors hypothesized that one pathophysiological mechanism involved in the impact of GCs on cerebellar maturation could be the under-expression of mGluR1 in the molecular layer where Purkinje cell dendritic tree outgrowth occurs. Furthermore, it should be noted that in rodents [7] as well as in humans [8], Purkinje dendritic maturation occurs during perinatal periods following a progressive outgrowth from the soma (located in the middle cerebellar cortical layer) towards the cerebellar upper molecular layer. ...
... The EPM is a test designed and validated to assess anxiety-like behaviors in rodents [22]. In the present authors' previous study [11] using an-other less-specific exploratory device (an open-field test), animals treated with betamethasone explored the arena significantly less compared to their age-matched controls. Because the lower exploratory activity of animals in this previous study occurred in the center of the open field, they interpret this behavior as an anxious state with avoidance of the ethologically "risky" central zone. ...
... Betamethasone is used for pregnant women at risk for preterm birth, between 24 and 34 weeks of pregnancy [1][2][3][4][5]. In laboratory animals, studies have reported that this treatment may cause changes in brain and neuroendocrine functions, suppression of maternal and fetal adrenal function, as well as problems with male fertility [6][7][8][9][10][11][12]. ...
... Betamethasone, a potent synthetic glucocorticoid, is generally the drug of choice for this antenatal therapy [4]. However, animal studies have shown that fetal exposure to synthetic glucocorticoids promotes an increased incidence of behavioral, metabolic and endocrine issues in the long-term [8,12,29]. Previous studies in rats have shown that betamethasone treatment can result in decreased testosterone levels and altered sperm parameters of male offspring [9,10]. ...
Antenatal betamethasone is used for accelerating fetal lung maturation for women at risk of preterm birth. Altered sperm parameters were reported in adult rats after intrauterine exposure to betamethasone. In this study, male rat offspring were assessed for reproductive development after dam exposure to betamethasone (0.1 mg/kg) or vehicle on Days 12, 13, 18 and 19 of pregnancy. The treatment resulted in reduction in the offspring body weight, delay in preputial separation, decreased seminal vesicle weight, testosterone levels and fertility, and increased testicular weight. In the testis, morphologically abnormal seminiferous tubules were observed, characterized by an irregular cell distribution with Sertoli cell that were displaced towards the tubular lumen. These cells expressed both Connexin 43 (Cx43) and Proliferative Nuclear Cell Antigen (PCNA). In conclusion, intrauterine betamethasone treatment appears to promote reproductive programming and impairment of rat sexual development and fertility due to, at least in part, unusual testicular disorders.
Preterm babies treated with synthetic glucocorticoids in utero exhibit behavioural alterations and disturbances in brain maturation during postnatal life. Accordingly, it has been shown in preclinical studies that SGC exposure at a clinical dose alters the presynaptic and postsynaptic structures and results in synaptic impairments. However, the precise mechanism by which SGC exposure impairs synaptic protein expression and its implications are not fully elucidated. Therefore, the purpose of this study was to investigate the effect of prenatal exposure to a clinical dose of betamethasone on the pre- and postsynaptic proteins expression in the developing rat cerebellum and prefrontal cortex, whose synchronized synaptic activity is crucial for motor control and learning.
Consequently, the first objective of the present study was to determine whether prenatal betamethasone -equivalent to the clinically used dose- alters cerebellar vermal and cortical expression of synaptophysin, synaptotagmin I, post-synaptic density protein 95 and gephyrin - four important pre- and post-synaptic proteins, respectively- at a relevant adolescent stage. In addition, our second objective was to assess whether prenatal betamethasone administration induced coordination impairment using a rotarod test.
On the other hand, it has been shown that the environmental enrichment is capable of improving synaptic transmission and recovering various behavioural impairments. Nevertheless, there is not enough information about the effect of this non-pharmacological preclinical approach on the regulation of this cerebellar and cortical synaptic proteins. Therefore, the third objective of this study was to examine whether environmental enrichment exposure could recover the possible molecular and behavioural impairments in the offspring at the same developmental stage.
The principal data showed that adolescent rats prenatally treated with betamethasone exhibited underexpression of synaptophysin in the vermal cerebellum, but not change in levels of synaptotagmin I, post-synaptic density protein 95 and gephyrin. Analysis of the same pre- and post-synaptic proteins no showed differences in the frontal cortex of the same rats. These results were accompanied by an increase in the number of falls in the rotarod test, when the speed of rotation was fixed and when it was in acceleration, which means motor coordination impairments. Importantly, we found that environmental enrichment restores the betamethasone-induced reduction in the cerebellar synaptophysin together with a recover in the motor coordination impairments in prenatally betamethasone-exposed adolescent rats.
