茶多酚抗晶状体上皮细胞凋亡的体外研究及机制

The study of green tea polyphenols inhibiting apoptosis of lens epithelial cell in vitro and relevant mechanism

目的:探讨抗氧化剂茶多酚对氧化损伤所诱发的晶状体上皮细胞凋亡的抑制作用和相关机制。方法:分离培养兔晶状体上皮细胞,茶多酚处理24～72h后,采用透射电镜、流式细胞术、凋亡细胞DNA片断分析检测茶多酚抗晶状体上皮细胞凋亡的作用,并用Western-blot检测凋亡相关蛋白bcl-2、Bax、caspase-3蛋白表达变化,揭示茶多酚抑制晶状体上皮细胞凋亡的相关机制。结果:氧化损伤型晶状体上皮细胞生理盐水处理组中,凋亡细胞增多,G1期细胞升高,DNA片断分析呈现典型的凋亡细胞特征性“梯状条带”;茶多酚处理组中,凋亡细胞明显减少,G1期细胞降低,未出现特征性“梯状条带”,凋亡相关蛋白bcl-2增多、Bax降低、caspase-3蛋白减少。结论:抗氧化剂茶多酚可抑制H2O2氧化损伤所诱导的兔晶状体上皮细胞凋亡并减轻或延缓白内障形成,其机制与bcl-2、Bax及细胞凋亡过程中最重要的终末执行酶caspase-3蛋白表达变化密切相关。

Objective： To investigate the inhibitory effect of Green Tea Polyphenols （GTP） on H2O2-induced lens epithelial cell apoptosis and relevant mechanism. Methods： Separated and cultivated lens epithelial cell, disposed that with GTP, then detected the inhibitory effect of GTP by electron transmission microscopy, flow cytometry and DNA fragmentation assay. The bcl - 2, Bax and caspase - 3 protein expression were measured with Western-blot in various groups. Results： The apoptosis cells and G1 phase cells increased in the group treated with sodium chloride solution, and the DNA ＂ladder＂ was found. In the group treated with GTP, the apoptosis cells and G1 phase cells decreased, and no DNA ＂ladder＂. The apoptosis protein bcl - 2 increased, however, the Bax and caspase - 3 protein decreased. Conclusion： The GTP can protect lens epithelial cells from the oxidative injury and restrain the apoptosis rate of lens epithelial cells and the mechanism was nearly correlated with bcl - 2, Bax and caspase - 3 protein.