牛磺酸对兔动脉粥样硬化血管平滑肌细胞凋亡的影响

目的:探讨牛磺酸对兔动脉粥样硬化血管平滑肌细胞凋亡及凋亡相关基因bcl-2、bax和caspase-3蛋白表达的影响.方法:将24只日本大耳白兔随机分为正常对照组、高脂模型组和牛磺酸组,14周后观察各组主动脉组织病理形态学改变,透射电镜观察斑块内平滑肌细胞超微结构变化,流式细胞术检测动脉粥样斑块内平滑肌细胞凋亡率,免疫组化染色法检测凋亡相关基因bcl-2和bax蛋白表达,Western blot蛋白印记法检测caspase-3蛋白表达.结果:高脂模型组与正常对照组比较,动脉内膜出现典型的斑块,管腔极度狭窄,典型的凋亡平滑肌细胞明显增多,平滑肌细胞凋亡率、bax及caspase-3蛋白表达升高(P<0.01),bcl-2蛋白表达降低(P<0.05).牛磺酸组与高脂模型组比较,主动脉斑块缩小,动脉管腔狭窄减轻,凋亡平滑肌细胞不典型且较少,平滑肌细胞凋亡率、bax蛋白表达及caspase-3蛋白表达降低(P<0.01),bcl-2蛋白表达升高(P<0.05).结论:牛磺酸可能通过对bcl-2、bax及caspase-3蛋白表达的调控而降低动脉斑块内过度凋亡的平滑肌细胞,从而抑制粥样斑块的形成.

Effect of taurine on the apoptosis of vascular smooth muscle cell in atherosclerotic rabbits

Objective:To study the effect of taurine on the apoptosis of vascular smooth muscle cells and expression of bcl-2, bax and caspase-3 proteins in atherosclerotic model of rabbits. Method:Twenty-four male Japanese white rabbits were divided into 3 groups: normol control group, high cholesterol group and taurine group.All rabbits were killed fourteen weeks later, and observed the pathomorphological changes in aorta wall and ultra-structures of VSMCS by electronic microscopy.The apototic rate of VSMCs was detected by flow cytometry. Expression of bcl-2 and bax proteins were detected by immunohistochemistry and expression of caspase-3 proteins was detected by Western blot. Result:In high cholesterol group the apoptotic rate of VSMCs, bax and caspase-3 were higher, the expression of bcl-2 proteins was lower than those in normal control group.The visible atheromatous plaque which caused the serious stenosis were observed and the apoptotic VSMCs were more in the atheromatous plaque in high cholesterol group. In taurine group the apoptotic rate of VSMCs was lower, the expression of bcl-2 proteins was higher(P<0.05), the expression of bax and caspase-3 proteins was lower(P<0.01) than those in high cholesterol group(P<0.01).The atheromatous plaque were decreased and the stenosis were reduced, and the apoptotic VSMCs were less and not typical. Conclusion:Taurine can decrease the apoptosis of VSMCs in the plaque by regulating the bcl-2、bax and caspase-3 proteins, which inhibits the formation of atherosclerotic plaque.