中文摘要：

背景：研究发现骨髓间充质干细胞上存在雌激素受体,雌激素通过调节骨髓间充质干细胞的增殖、分化特性发挥促成骨作用。目的：观察17β-雌二醇对骨髓间充质干细胞向成骨细胞分化的诱导作用,并探讨其作用机制。方法：在基础成骨诱导培养基培养的第3代大鼠骨髓间充质干细胞中分别加入0（对照组）,0.001,0.01,0.1nmol/L17β-雌二醇干预。Elisa法检测培养的骨髓间充质干细胞分泌Ⅰ型胶原的水平,RT-PCR及Western blotting法分别检测Runx2因子mRNA及蛋白水平。结果与结论：与对照组比较,在给予0.001,0.01,0.1nmol/L17β-雌二醇干预后第5天,骨髓间充质干细胞Ⅰ型胶原表达显著升高（P〈0.05）,第7天仍旧呈高表达（P〈0.05）。同时,在17β-雌二醇干预的第5,7天,Runx2因子mRNA及蛋白表达水平随17β-雌二醇浓度的增加而升高（P〈0.05）,并呈剂量依赖性。表明17β-雌二醇可诱导骨髓间充质干细胞向成骨细胞转化,其可能通过上调Runx2因子表达发挥促成骨作用。

英文摘要：

BACKGROUND：The estrogen receptor exists in bone marrow mesenchymal stem cells and estrogen promotes bone formation by regulating the proliferation and differentiation of bone marrow mesenchymal stem cells.OBJECTIVE：To explore the effects of 17β-estradiol on the osteogenic differentiation of bone marrow mesenchymal stem cells（MSCs） and the underlying mechanism.METHODS：MSCs were separated,purified,cultured and expanded.Different concentrations of 17β-estradiol was administrated to MSCs for some period.The level of type I collagen in culture medium was detected by Elisa method,and the expression of Runx2 mRNA and protein was analyzed by RT-PCR or Western blotting methods,respectively.RESULTS：Compared with the control group,type I collagen expression in the MSCs was significantly increased on the 5th day after administration of 0.001,0.01,0.1 nmol/L 17β estradiol（P 0.05） and it maintained high expression on the 7th day（P 0.05）.Runx2 mRNA expression increased in a dose-dependent manner on the 5th and 7th days after administration of 17 β-estradiol（P 0.05）.These findings suggest that 17β-estradiol can induce the osteogenic differentiation of MSCs,which occurs possibly by upregulation of Runx2 expression.