不同浓度雌激素对大鼠膀胱颈平滑肌细胞增殖与凋亡的影响

目的:探讨不同浓度17β-雌二醇(E2)对大鼠膀胱颈平滑肌细胞(BSMC)增殖与凋亡的影响。方法:无菌切取大鼠膀胱颈,应用酶消化法行原代细胞培养。取3-4代传代细胞,用α-平滑肌肌动蛋白抗体免疫组织化学法鉴定细胞成分,选取平滑肌成分大于85%者,分别加入不同浓度E2(0.1-100 nmol/L)。于处理72 h后收获细胞,应用流式细胞仪检测细胞周期、细胞凋亡及其相关蛋白CyclinD1,应用Western blotting法检测Bcl-2和Bax表达。结果:E2(0.1-10 nmol/L)促进BSMC从G1期向S过渡(G0/G1期比率显著低于对照组细胞,而S期和G2/M期比率显著高于对照组细胞,P<0.05),并伴随Cyclin D1蛋白表达显著增高。而大剂量E2(100 nmol/L)则使细胞凋亡率显著升高,并伴随Bax表达显著增加。结论:小剂量E2能够促进合成型BSMC增殖,其机制是影响Cyclin D1表达,加速G1期向S过渡;大剂量E2则通过增加Bax促进细胞凋亡。

Effects of Different Concentrations of Estrogen on Proliferation and Apoptosis of Synthetic Bladder Neck Smooth Muscle Cells

Objective: To investigate the effect of different concentrations of 17β-estradiol(E2) on proliferation and apoptosis of bladder neck smooth muscle cells(BSMCs) and the possible underlying mechanisms.Methods: The synthetic(subcultured for 3-4 passages) rat bladder neck smooth muscle cells were obtained by enzyme-digesting method and exposed to gradient concentrations(0.1-1 00 nmol/L) of E2 for 72 h.The α-smooth muscle actin antibody was used to identify the cells by immunohistochemistry.The progression of cell cycle,the apoptosis and the expressions of CyclinD1 protein were examined by flow cytometry.Bcl-2 and Bax proteins were detected via Western blotting method.Results: E2(0.1-10 nmol/L) promoted BSMC proliferation by accelerating their cell cycle progression from G1 to S phases compared with that of control group(0 nmol/L E2).The rates of the BSMC at S and G2/M phase were significantly increased,while those at G0/G1 phase decreased.This was accompanied by an up-regulation of CyclinD1 expression.However,high dose of E2(10 nmol/L and 100 nmol/L) increased the rate of apoptosis of the cells accompanied by a significant raise of Bax expression and the ratio of Bax/Bcl-2.Conclusion: The effect of E2 on subcultured(synthetic) BSMC is bilateral: it promotes BSMC proliferation by enhancing the expression of CyclinD1 which accelerates G1 to S phase transition,and on the other hand,it induces apoptosis of the cells by up-regulating the expression of Bax.