| Objective: osteoarthritis(Osteoarthritis,OA)is a chronic joint degenerative disease with a wide range of people,a long course of disease and a high rate of disability and teratogenicity.At present,the clinical treatment of OA can only alleviate the disease progression or control the pain symptoms to a certain extent,and the late stage can only choose surgical treatment such as joint replacement.At present,stem cell transplantation has made great progress,and it has been widely studied because of its potential of multidirectional differentiation,immunomodulatory function and strong ability of proliferation in vitro.In the past,it was believed that articular cartilage contained less cells and blood supply,and had poor self-repair ability.Recent studies have shown that normal and OA articular cartilage contain tissue-specific stem / progenitor cells,called cartilage stem / progenitor cells(cartilage-derived stem / progenitor cells,CSPCs),which not only have the same stem cell characteristics,but also have the characteristics of easier differentiation into cartilage.However,the stem cell characteristics and mechanism of CSPCs in inflammatory environment have not been fully elucidated.Notch signaling pathway is a relatively conservative pathway,which has been proved to play a key role in regulating key processes in embryonic development,cell fate determination,proliferation,differentiation and homeostasis.The purpose of this study was to explore the effects of Notch signaling pathway on the proliferation,migration and multidirectional differentiation of CSPCs in inflammatory environment.Methods: CSPCs was taken from 6-day-old experimental SD rats.CSPCs was stimulated by IL-1 β to induce inflammation,and the inflammatory microenvironment of OA was simulated in vitro.The proliferative ability of CSPCs was detected by plate cloning test.Transwell and scratch test were used to detect the change of CSPCs migration ability.RT-PCR and Western Blot were used to detect the changes of cellular inflammatory cytokines,the expression of Notch signal pathway and the expression of genes related to CSPCs osteogenesis,adipogenesis and chondrogenic differentiation.The model of OA was established in the right hindlimb of rats by meniscus instability(destabilization of the medial meniscus,DMM).Four weeks after operation,CSPCs,CSPCs+DAPT was injected into the knee joint cavity of CSPCs group and CSPCs+DAPT group respectively.Pelletier score were used to evaluate the cartilage injury on the surface of femoral condyle.Results:(1)In inflammatory environment,the proliferation and migration ability of CSPCs decreased,the expression of chondrogenic differentiation related genes COL2A1,SOX9 and ACAN decreased significantly,while the expression of osteogenic differentiation related genes RUNX2,SPP1 and adipogenic differentiation related genes CEBP/ α and PPAR γ increased significantly.(2)the expression of Notch signal pathway receptor NOTCH1,ligand JAGGED1,transcription factor RBPJK and downstream molecule HES1 increased significantly in inflammatory environment.the inhibition of Notch signal pathway by DAPT can reduce the release of inflammatory factors in the environment,restore the proliferation and migration ability of CSPCs,and improve the chondrogenic differentiation ability of CSPCs.(3)Intraarticular injection of CSPCs+DAPT after DMM in rats can significantly delay the progression of OA and repair worn cartilage.Conclusions: In inflammatory environment,Notch signal pathway is highly expressed and inhibits the ability of proliferation,migration and chondrogenic differentiation of CSPCs.Inhibition of this signal pathway can restore the ability of proliferation,migration and chondrogenic differentiation of CSPCs,which is closely related to the occurrence,development and treatment of OA. |
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