Animal Model Of Tendinopathy And Treatment-an In Vitro And In Vivo Study

Objective: Tendinopathy is a common problem.Its pathogenesis is complex and not fully understood.Accordingly,current treatment protocols are just empirical but are not clear.An important cause for this status is the lack of good animal models of tendinopathy.The aim of this study is to establish a new animal model of tendinopathy,and study the efficacy and mechanism of current clinical treatments for tendinopathy based on this model.Our results,while offering new insights into the establishment of tendinopathy model,may assist in future strategies to treat tendinopathy.Methods:Tendon stem cell(TSCs)were isolated and culture in vitro.Various concentrations of kartogenin(KGN)were added into the culture medium to study the effect of KGN on TSCs,including cell proliferation,differentiation,and mRNA expression levels.Then KGN was injected into or KGN-alginate bead was implanted into tendons to induce tendinopathic histopathogenesis.After establishment of tendinopathy model,current clinical treatment PRP injection was applied in the early stage and late stage of tendinopathy to observe the effect of PRP to improve tendon repair and healing.Finally,a most commonly used NSAIDs,Toradol(ketorolac tromethamine,KT)was studied in vitro and in vivo on tendon stem cells and tendon tissue.Results: After isolation and culture of TSCs,various concentrations of KGN was added into cell culture medium.KGN significantly promote TSCs differentiation into chondrocytes,with higher level of chondrogenic biomarkers expression.Implantation of KGN beads can induce tendinopathic pathogenesis in SD rats' Achilles tendons,which show important histopathological characteristics,including hypercellularity,loss of collagen organization,hypervascularity,GAG accumulation,rounding of cell nuclei or acquisition of chondrocyte phenotype,and calcified bone-like tissue.Based on this model,PRP was injected percutaneously to treat tendinopathy.In early stage of the disease,PRP injection was able to significantly inhibit the development of tendinopathy and promote the repair of the damaged tendon.In late stage,cartilage-like tissue was formed,PRP injection was not able to facilitate tendon repair.Furthermore,we resected and removed the cartilage-like tissue and implanted PRP gel into the tendon defect,and found that PRP improved tendon healing significantly.Therefore,removal of non-tendon tissues is suggested to perform before PRP implantation to treat tendinopathy at late stage.Finally,both in vitro and in vivo results show that Toradol is toxic to tendon cells and can destroy tendon fiber structure when injected especially at high concentrations.Conclusions: KGN promotes TSCs differentiation into chondrocytes in vitro,and can induce tendinopathic pathogenesis in vivo.PRP percutaneous injection in early stage prevents further pathogenesis of tendinopathy and promotes tendon repair,while shows no significant beneficial effect in late stage.After non-tendon tissues removal,PRP implantation facilitated significantly the repair of tendon.The clinically commonly used NSAID,Toradol,is toxic to tendon cells in vitro and damages tendon structure after injection in vivo.Objective:A stroke is the rapidly developing loss of brain function due to a disturbance in the blood vessels supplying blood to the brain.Induced pluripotent stem cells(iPSCs)differentiating into neural stem cells(NSCs)in vitro are an alternative cell source for transplantation in treating stoke.The aim of this study is to explore the mechanisms and effects of iPSCs-derived NSCs to improve nerve repair and function store after transplantation into the striatum in the model of middle cerebral artery occlusion(MCAO).Methods: iPSCs were induced to differentiate into NSCs with RA plus serum-free medium in vitro.After anesthesia,a 4-0 nylon intraluminal suture was introduced from the minimal incision of the external carotid artery into the internal carotid artery about a depth of 180mm-200 mm until it blocked the origin of the MCA to establish the model of MCAO.The CM-Di I labelled NSCs were injected into the striatum,compared with the sham group and PBS injection group.Cell survival,migration and differentiation were measured and revcoery of neurological function were assessed.Results: iPSCs and ESCs expressed high levels of Oct4,Sox2 and Nanog.NSCs derived from iPSCs and ESCs expressed Nestin,?-tubulin and GFAP.7 days after cell transplantation,CM-Di I labeled cells(68.2 ± 2.3 count / field)were found around striatum.Immunochemical staining showed that CM-Di I labeled cells expressed Nestin(68.5 ± 2.8%),and ?-tubullin(25.7 ± 12.3%).3 weeks after transplantation,neurologic recovery was significantly better in cell transplantation group than other groups.Conclusions: RA combined serum-free medium can induce differentiation of i PSC to NSC.Transplanted iPSCs-derived NSCs can survive,migrate,and differentiate into nerve cells in vivo,and can improve the function of the damaged nerve.