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目的 探讨Toll样受体4(TLR-4)在骨髓间充质干细胞(BMSCs)成骨过程各阶段的作用及可能机制.方法 全骨髓培养法获取大鼠原代BMSCs ,并采用流式细胞术鉴定.将细胞分为TLR-4激活组(A组)和空白对照组(B组).成骨诱导培养14 d后 ,采用Western blot法检测Ⅰ型胶原和骨钙素表达 ;矿化诱导培养10 d后 ,采用碱性磷酸酶和茜素红染色观察成骨细胞染色强度 , Western blot法检测β-连环蛋白表达.结果 成功培养BMSCs ,CD29、CD95、CD44和 HLA-Ⅰ表达阳性 ,CD14、CD34表达阴性.与B组相比 ,A组Ⅰ型胶原和骨钙素表达增加 ,成骨细胞的染色强度减弱 ,β-连环蛋白表达减少(P<0 .01).结论 TLR-4能促进干细胞向成骨细胞分化 ,但在成骨细胞矿化阶段起抑制作用 ;这可能与TLR-4对Wnt信号通路的抑制有关.“,”Objective To investigate the effect and underlying mechanism of Toll like receptor-4 (TLR-4) on the osteogenetic process of bone marrow mesenchymal stem cells (BMSCs) .Methods Primary BMSCs were isolated from SD rats by whole bone marrow culture and identified by flow cytometry .Both BMSCs and osteoblasts were divided into two groups of A (TLR-4 activated by lipopolysaccharide 10 ng/ml) and B (blank control) .After BMSCs were cultured in osteogenic medium for 14 days ,collagen typeⅠ and osteocalcin expressions were detected by Western blot .After osteoblasts were cultured in mineralized medium for 10 days ,osteoblasts were stained by alkaline phosphatase and alizarin red ,and β-catenin expression was determined by Western blot .Results Primary BMSCs were successfully cultured with positive expressions of CD29 ,CD95 ,CD44 ,HLA-Ⅰand negative expressions of CD14 ,CD34 .Compared with group B ,collagen typeⅠ and osteocalcin expressions were increased ,staining intensity of osteoblasts was weakened ,and β-catenin expression was decreased in group A (P<0 .01) .Conclusion TLR-4 promotes stem cells to differentiate into osteoblasts ,but has an inhibitory effect on the mineralization stage of osteoblasts ,which may be related with the suppression of Wnt signaling pathway .