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Note that the loose scar tissues were found in the decorticated areas treated with 1.0 mg/ml group and 2.0 mg/ml HCPT group. Dense scar tissue was found in the decorticated areas treated with saline. The sections were stained with hematoxylin-eosin(200×).
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10-Hydroxycamptothecin could reduce intraarticular adhesion by inhibiting fibroblasts proliferation after knee surgery. However, the ideal concentration of hydroxycamptothecin have not been defined. This study was tried to verify the optimal concentration of 10-hydroxycamptothecin in preventing knee intraarticular adhesion. Sixty rabbits were rando...
Citations
... Besides, 10-hydroxycamptothecine (HCPT) and mitomycin (MMC) C were reported to selectively induce cycle arrest or apoptosis of fibroblasts, thereby showing a dose-dependent adhesion prevention effectiveness [72,[258][259][260]. The optimal concentration of HCPT in reducing intraarticular adhesion after knee surgery in rabbits was demonstrated to be 1.0 mg/ml when topically applicated [261]. Whereas, the side effect has been reported that peritoneal washing with MMC solutions (0.5 mg/kg and 1 mg/kg) caused animal death even though it was beneficial in decreasing the severity of adhesion band formation. ...
... Moreover, drugs or small-molecule inhibitors, such as Tocilizumab, an anti-human IL-6Rα monoclonal antibody [296], and medicines from natural sources with fewer side effects need to be taken into consideration. However, the extent of side effects is usually related to the dose of drugs, and only limited drugs have been researched [261,328]. Hence, more efforts need to be taken to obtain the safe and effective doses of drugs used in specific tissues for POA prevention. Moreover, the practical dose of drugs loaded in biomaterials depends on the released drugs. ...
Postoperative adhesion (POA) widely occurs in soft tissues and usually leads to chronic pain, dysfunction of adjacent organs and some acute complications, seriously reducing patients' quality of life and even being life-threatening. Except for adhesiolysis, there are few effective methods to release existing adhesion. However, it requires a second operation and inpatient care and usually triggers recurrent adhesion in a great incidence. Hence, preventing POA formation has been regarded as the most effective clinical strategy. Biomaterials have attracted great attention in preventing POA because they can act as both barriers and drug carriers. Nevertheless, even though much reported research has been demonstrated their efficacy on POA inhibition to a certain extent, thoroughly preventing POA formation is still challenging. Meanwhile, most biomaterials for POA prevention were designed based on limited experiences, not a solid theoretical basis, showing blindness. Hence, we aimed to provide guidance for designing anti-adhesion materials applied in different soft tissues based on the mechanisms of POA occurrence and development. We first classified the postoperative adhesions into four categories according to the different components of diverse adhesion tissues, and named them as "membranous adhesion", "vascular adhesion", "adhesive adhesion" and "scarred adhesion", respectively. Then, the process of the occurrence and development of POA were analyzed, and the main influencing factors in different stages were clarified. Further, we proposed seven strategies for POA prevention by using biomaterials according to these influencing factors. Meanwhile, the relevant practices were summarized according to the corresponding strategies and the future perspectives were analyzed.
... A rabbit knee arthrofibrosis model was established according to a previous study [20]. Briefly, anaesthesia was induced. ...
Post-surgery arthrofibrosis is one of the most restrictive factors in the development of intra-articular surgery and has presented tremendous obstacles for most orthopaedic surgeons. Tanshinone IIA (Tan IIA), a key active ingredient of Den-shen, has been used to treat fibrosis-related diseases, such as pulmonary, hepatic and myocardial fibrosis. In the present study, we aimed to investigate the effects of Tan IIA on post-surgery arthrofibrosis in vivo and in vitro. Histological analysis indicated that topical application of Tan IIA (10 mg/mL) could significantly alleviate postsurgery arthrofibrosis in rabbits. Immunohistochemistry results showed that proliferating cell nuclear antigen (PCNA) and tubulin protein expression was inhibited, whereas LC3 was activated in vivo. In vitro, EdU and flow cytometry assays demonstrated that Tan IIA could inhibit fibroblast proliferation by arresting cells in G2 phase. Scratch, Transwell and cytoskeleton protein immunofluorescence assays revealed that fibroblast migration was attenuated. Interestingly, LC3 immunofluorescence staining and transmission electron microscopy indicated that autophagy flux could be induced in fibroblasts by Tan IIA. However, the inhibitory effects of Tan IIA against fibroblast proliferation and migration were partially restored when fibroblast autophagy was suppressed after combined treatment with the autophagy inhibitor 3-methyladenine (3-MA). Finally, the expression of p-mTOR was suppressed in a dose-dependent manner after Tan IIA treatment but partially restored when Tan IIA treatment was combined with 3-MA intervention. The inhibitory effect of Tan IIA against fibroblast proliferation and migration may be related to autophagy induction mediated by the PI3K and AMPK-mTOR signaling pathway.
... An intraarticular adhesion animal model was built based on previous scholars' studies [20]. New Zealand rabbits were first given an intravenous injection of 2% pentobarbital (1.5 ml/kg) to achieve general anesthesia. ...
Background:
Intraarticular scar adhesion refers to a serious complication caused by knee surgery or trauma, leading to various sequelae (e.g., articular cartilage degeneration and knee joint stiffness). Artesunate (ART) has exhibited an effect to suppress fibroblast proliferation, whereas the exact mechanism remains unclear. This study aims to delve into the possible mechanism of ART in suppressing joint adhesion.
Methods:
The effect of ART on reduced intraarticular adhesions was ascertained by histological staining and immunohistochemical analysis through vivo experiments. Cell Counting Kit-8 (CCK-8) assay, Western blot analysis, flow cytometry, and tunnel staining were used to detect the effect of ART in promoting fibroblast apoptosis and delve into its possible signaling pathway.
Results:
The results of hematoxylin-eosin (HE) staining suggested that the number of fibroblasts decreased with the increase in ART concentration. The results of Masson staining were similar, with the increase in concentration, the collagen content decreased. Immunohistochemical results showed that the expression of endoplasmic reticulum stress (ERS) characteristic proteins 78 kDa glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) increased in a concentration-dependent manner. CCK-8 results suggested that ART could inhibit fibroblast viability in a concentration- and time-dependent manner. Results of flow cytometry, tunnel staining, and Western blot suggested the apoptosis of fibroblasts occurred after ART treatment. Cells with caspase inhibitors were treated, and apoptotic proteins cleaved-poly ADP-ribose polymerase (cleaved PARP) and cleaved-caspase 3 were detected; the results showed that the apoptotic effect of ART was reduced. The expressions of ERS-related protein CHOP and apoptosis-related protein Bax were upregulated, while the expression of Bcl-2 was downregulated, and the ratio of Bax/Bcl-2 increased in a concentration-dependent manner. Continuous detection of PRKR-like ER kinase (PERK) pathway-related proteins showed that the expression of p-PERK and phosphorylating eukaryotic initiation factor 2α (p-eIF2α) increased in a time-dependent and concentration-dependent manner. PERK pathway inhibitors could partially inhibit ART-mediated apoptosis through PERK pathway.
Conclusions:
ART can promote fibroblast apoptosis through PERK pathway, a classical ERS pathway, and thus prevent fibrosis in the surgical area after joint surgery.
... Many investigations have suggested that antifi brotic agents may be of potential use in preventing or combating arthrofi brosis because they inhibit the TGF-β signaling pathway. 1,13,28,56,57,85,89,182,195 However, the effectiveness of various agents such as decorin, hyaluronic acid, chitosan, mitomycin C, and various IL-1 receptor antagonists in high-level human studies for early or later-stage arthrofi brosis has not been investigated to date. ...
... The study showed that the local application of 0.2 mg/ml RAPA could reduce intraarticular fibrous adhesion through inhibition of fibroblast proliferation and collagen synthesis in rabbit models. Currently, the mechanisms of intraarticular adhesion formation still remain unclear, but fibroblasts were generally recognized as a major reason for the formation of intraarticular adhesion [30,31]. Following knee surgery, many growth factors and inflammatory cytokines will migrate to the surgical sites, where they will Fig. 1 Hydroxyproline content in intraarticular scar tissue in the RAPA-treated groups and the control group. ...
Background
The formation of intraarticular adhesion is a common complication after total knee arthroplasty or anterior cruciate ligament reconstruction. Previously, little research was reported regarding whether the local application of rapamycin (RAPA) could reduce intraarticular adhesion following knee surgery. In our present study, we determined the therapeutic effect of RAPA by local application on the reduction of intraarticular adhesion following knee surgery in rabbits.
Methods
In this study, we built the model of knee surgery according to a previous study. The decorticated areas of the cortical bone were exposed and covered with cotton pads soaked with different concentrations of RAPA or physiological saline for 10 min. All of the rabbits were euthanized 4 weeks after the surgery. Macroscopic evaluation of the hydroxyproline content, the histological morphological analysis and collagen density and fibroblast density were used to evaluate the effect of RAPA on reducing intraarticular adhesion.
Results
The results shown that RAPA could significantly inhibit the proliferation of fibroblasts and reduce collagen synthesis; in the rabbit model of knee surgery, there were weak scar tissues around the decorticated areas in the 0.2 mg/ml RAPA group; moderate scar tissues were found in the 0.1 mg/ml RAPA group. However, severe fibrous adhesions were found in the 0.05 mg/ml RAPA group and the control group. The hydroxyproline content and the fibroblast density in the 0.2 mg/ml and 0.1 mg/ml RAPA groups were significantly less than those of the control group.
Conclusions
We concluded that the local application of RAPA could reduce intraarticular adhesion after knee surgery in the rabbit model; this effect was mediated by inhibition of fibroblast proliferation and collagen synthesis, which may provide a new method for reducing intraarticular adhesion after clinical knee surgery.
... No effective treatments are widely accepted [3]. A variety of methods have been developed to prevent intra-articular adhesions in animal models and humans, including arthroscopic lysis of adhesions, intra-articular and/or mitomycin C application, continuous corticosteroid administration, and hyaluronan derivative gel [4][5][6][7][8]. ...
... The rabbit knee intra-articular adhesion model was performed according to the previous protocol [3]. Sterile conditions were prepared beforehand. ...
... Selecting 3 rabbits randomly per group, macroscopic evaluation was performed 4 weeks post-surgery. The surgical knee was reopened with re-anesthesia, and the presence and severity of intra-articular adhesions was evaluated, with the results based on the visual scoring system (Table 1) [1][2][3]. ...
Background
Intra-articular adhesion after knee surgery is a common and serious complication that presents a challenging problem for orthopedic surgeons. Verapamil (VP), a widely used calcium channel blocker, has been shown to prevent synthesis/secretion of extracellular matrix molecules. The object of this study was to investigate the effects of VP on the prevention of joint adhesion in post-surgery rabbits.
Material/Methods
A controlled double-blinded study was conducted in 40 healthy New Zealand white rabbits divided randomly into 4 groups according to the treatment method, with 10 in each group: 1) 1 mg/ml VP treatment group; 2) 2.5 mg/ml VP treatment group; 3) 5 mg/ml VP treatment group; 4) control group. Rabbits underwent surgery through the medial parapatellar approach and both lateral sides and the medial of the femoral condyle were surgically exposed. After treatment, the surgical limbs were subjected to extra-articular knee-joint immobilization in the full flexed position employing Kirschner wires for 4 weeks.
Results
The knee surgery was successfully performed on all rabbits. The rabbits were killed 4 weeks post-operatively. The histological evaluation, hydroxyproline content, visual score, fibroblasts density, and vimentin expressional levels were conducted to assess the effect of VP on preventing joint adhesion.
Conclusions
In our rabbit model of knee surgery, intra-articular application of VP was able to decrease intra-articular adhesion formation after surgery. VP could prevent rabbit intra-articular adhesion in a dose-dependent manner and the highest concentration used in the study (5 mg/ml) proved to be the most effective.
Corneal fibrosis is a common outcome of inappropriate repair associated with trauma or ocular infection. Altered biomechanical properties with increased corneal stiffness is a feature of fibrosis that cause corneal opacities, resulting in severe visual impairment and even blindness. The present study aims to determine the effect of hydroxycamptothecin (HCPT) and matrix stiffness on transforming growth factor-β1 (TGF-β1)-induced fibrotic processes in human corneal fibroblasts (HTK cells). HTK cells were cultured on substrates with different stiffnesses ("soft", ∼261 kPa; "stiff", ∼2.5 × 103 kPa) and on tissue culture plastic (TCP, ∼106 kPa) and simultaneously treated with or without 1 μg/mL HCPT and 10 ng/mL TGF-β1. We found that HCPT induced decreased cell viability and antiproliferative effects on HTK cells. TGF-β1-induced expression of fibrosis-related genes (FN1, ACTA2) was reduced if the cells were simultaneously treated with HCPT. Substrate stiffness did not affect the expression of fibrosis-related genes. The TGF-β1 induced expression of FN1 on both soft and stiff substrates was reduced if cells were simultaneously treated with HCPT. However, this trend was not seen for ACTA2, i.e., the TGF-β1 induced expression of ACTA2 was not reduced by simultaneous treatment of HCPT in either soft or stiff substrate. Instead, HCPT treatment in the presence of TGF-β1 resulted in increased gene expression of keratocyte phenotype makers (LUM, KERA, AQP1, CHTS6) on both substrate stiffnesses. In addition, the protein expression of keratocyte phenotype makers LUM and ALDH3 was increased in HTK cells simultaneously treated with TGF-β1 and HCPT on stiff substrate as compared to control, i.e., without HCPT. In conclusion, we found that HCPT can reduce TGF-β1-induced fibrosis and promote the keratocyte phenotype in a substrate stiffness dependent manner. Thus, HCPT stimulation might be an approach to stimulate keratocytes in the appropriate healing stage to avoid or reverse fibrosis and achieve more optimal corneal wound healing.
Staphylococcus aureus (S. aureus) is the most common pathogen causing skin and soft tissue infections. The emergence and spread of methicillin-resistant S. aureus (MRSA) pose a major challenge for the treatment of infected wounds because of its high resistance and enhanced virulence. The overexpression of reactive oxygen species (ROS) at the site of skin wounds also exacerbates inflammation, leading to slower healing and severe scarring. Therefore, comprehensive strategy against MRSA-infected wounds is needed in clinical practice. Interference with quorum sensing (QS), a process of bacterial cell-to-cell chemical communication, has been considered a promising strategy to reduce the virulence and pathogenicity of MRSA. Herein, we designed a ROS-scavenging hydrogel loaded with a type of bacterial QS inhibitor, hyper-branched poly-L-lysine (HBPL), which has efficient bactericidal ability against planktonic and biofilm-embedded MRSA. We found that this multifunction hydrogel showed excellent anti-oxidative effects against different types of ROS, and it could inhibit the QS system, metabolic activity, and bacterial virulence. In vivo, the ROS-scavenging HBPL hydrogel efficiently accelerated the healing of MRSA-infected full-thickness skin defect by blocking QS, killing bacteria, suppressing inflammation, and promoting angiogenesis. Together, our results offer a new insight for scarless healing of MRSA-infected cutaneous wounds.
Background
The prevention of surgery-induced intraarticular fibrosis remains a challenge following orthopedic surgery. Homoharringtonine (HHT) has been reported to have positive effects in preventing various kinds of fibrosis. However, little is known regarding its effect as well as the potential mechanism of HHT in preventing surgery-induced intraarticular fibrosis.
Methods
Various concentrations of HHTs were locally applied in vivo to reduce knee intraarticular fibrosis in rabbits. Histological macroscopic assessments such as hematoxylin and eosin (HE) staining, Masson’s trichrome staining, and Picric-sirius red polarized light were used to evaluate the effect of HHT in reducing intraarticular fibrosis. CCK-8, cell cycle assay, and EdU incorporation assay were used in vitro to detect HHT’s effect on inhibiting fibroblast viability and proliferation. The effect of HHT on fibroblast differentiation, extracellular matrix production, and apoptosis were evaluated by western blot, flow cytometry, immunofluorescent staining, and TUNEL analysis. Moreover, the expressions of PI3K/AKT/mTOR signaling pathway were detected.
Results
The results demonstrated that HHT could reduce the formation of intraarticular fibrosis. HHT was also found to induce fibroblast apoptotic cell death in a dose- and time-dependent manner in vitro. Moreover, HHT could effectively inhibit the production of the extracellular matrix secreted by fibroblasts and inhibited the expression of p-PI3K, p-AKT, and p-mTOR in a dose-dependent manner. After treating with insulin-like growth factor-1 (IGF-1), an activator of the PI3K/AKT axis, the expressions of pro-apoptosis-related proteins were decreased, and the fibroblast apoptosis rate was also inhibited.
Conclusions
In conclusion, this study demonstrated that HHT could reduce the formation of intraarticular fibrosis through the inhibition of fibroblast proliferation, extracellular matrix production, and the induction of fibroblast apoptotic cell death. Furthermore, its potential mechanism may be through the suppression of the PI3K/AKT/mTOR signaling pathway.
This study tested whether cell cycle inhibitor mitomycin C (MMC) prevents arthrogenic contracture progression during remobilization by inhibiting fibroblast proliferation and fibrosis in the joint capsule. Rat knees were immobilized in a flexed position to generate flexion contracture. After three weeks, the fixation device was removed and rat knees were allowed to freely move for one week. Immediately after and three days after fixator removal, rats received intra-articular injections of MMC or saline. The passive extension range of motion (ROM) was measured before and after myotomy of the knee flexors to distinguish myogenic and arthrogenic contractures. In addition, both cellularity and fibrosis in the posterior joint capsule were assessed histologically. Joint immobilization significantly decreased ROMs both before and after myotomy compared with untreated controls. In saline-injected knees, remobilization increased ROM before myotomy, but further decreased that after myotomy compared with that of knees immediately after three weeks of immobilization. Histological analysis revealed that hypercellularity, mainly due to fibroblast proliferation, and fibrosis characterized by increases in collagen density and joint capsule thickness occurred after remobilization in saline-injected knees. Conversely, MMC injections were able to prevent the remobilization-enhanced reduction of ROM after myotomy by inhibiting both hypercellularity and joint capsule fibrosis. Our results suggest that joint capsule fibrosis accompanied by fibroblast proliferation is a potential cause of arthrogenic contracture progression during remobilization, and that inhibiting fibroblast proliferation may constitute an effective remedy.
