高血糖微环境通过let-7b-5p/CFTR通路抑制肌腱干细胞增殖分化的机制研究OA

Objective:This study aimed to investigate,at the in vitro level,the specific mechanism by which a hyperglyce-mic microenvironment inhibits tendon-derived stem cells(TDSCs)proliferation and differentiation through the cystic fibrosis transmembrane conductance regulator(CFTR).Methods:TDSCs were isolated from Sprague-Dawley rats,and their proliferation was evaluated by MTT assay.The ex-pression of CFTR and tendon-related markers(Tnmd,Col-1 and Sex)were determined by qRT-PCR and Western blot-ting.Candidate miRNAs capable of binding CFTR mRNA were identified by bioinformatic analyses,and the targeting relationship was validated by a dual-luciferase reporter assay in HEK293T cells.CFTR was further overexpressed in TDSCs to verify whether it could reverse the inhibitory effects of the high-glucose microenvironment on TDSC proliferation and differentiation.Results:In TDSCs cultured under different glucose concentrations,the high-glucose microenvironment significantly downregulated the mRNA and protein expression of CFTR and the tendon-related markers Tnmd,Col-1 and Scx.Bioinformatic analyses combined with experimental validation showed that let-7b-5p was significantly upregulated in the high-glucose microenvironment and directly bound to the 3'UTR of CFTR mRNA,thereby negatively regulating CFTR expression at the post-transcriptional level.Overexpression of CFTR effectively reversed the inhibitory effects of the high-glucose microenvironment and the let-7b-5p mimic on TDSC proliferation and differentiation.Conclu-sion:A hyperglycemic microenvironment inhibits TDSC proliferation and differentiation in vitro via the let-7b-5p/CFTR pathway,which may represent a potential molecular mechanism underlying diabetes-induced poor tendon-to-bone healing.