PTEN 在动脉粥样硬化中的表达及对血管内皮细胞增殖凋亡的影响研究

目的:探讨第10号染色体同源缺失性磷酸酶鄄张力蛋白(PTEN)在动脉粥样硬化中的表达及对血管内皮细胞(VEC)增殖凋亡的影响。方法:构建动脉粥样硬化小鼠模型,Real-time PCR和Western blot检测动脉粥样硬化组织中PTEN水平;用不同浓度的氧化低密度脂蛋白(ox-LDL)处理大鼠VEC,噻唑蓝(MTT)检测细胞增殖活性。VEC转染PTEN过表达载体(pSicoR-PTEN),用ox-LDL 处理细胞,Real-time PCR和Western blot检测PTEN水平,MTT检测细胞增殖,流式细胞术检测细胞凋亡,Western blot 检测磷酸化的STAT3(p-STAT3)、信号转导与转录因子3(STAT3)、活化的含半胱氨酸的天冬氨酸蛋白水解酶3(Cleaved Caspase-3)水平。结果:动脉粥样硬化组织中的PTEN水平明显低于正常的动脉组织(P<0.05)。不同浓度的ox-LDL处理后的VEC存活率明显降低,并且细胞存活率随着ox-LDL浓度的升高而降低。Ox-LDL作用后的VEC中PTEN表达水平下降,而转染pSicoR-PTEN后可以提高VEC中PTEN表达水平。Ox-LDL处理后的VEC凋亡率增加,细胞中Cleaved Caspase-3水平升高,p-STAT3 水平下降,与正常培养的VEC相比差异具有统计学意义(P<0.05)。转染pSicoR-PTEN后VEC 经过ox-LDL处理后细胞存活率、p-STAT3 水平明显升高,而细胞凋亡率、Cleaved Caspase-3水平明显降低,与单纯ox-LDL处理后的细胞相比差异具有统计学意义(P<0.05)。结论:PTEN 在动脉粥样硬化组织中表达下调,PTEN 可以逆转ox-LDL对VEC增殖抑制和凋亡促进作用,作用机制可能与STAT3 信号通路的激活有关。

Expression of PTEN in atherosclerosis and its effect on proliferation and apoptosis of vascular endothelial cells

Objective:To investigate the expression of PTEN in atherosclerosis and its effect on the proliferation and apoptosis of vascular endothelial cell ( VEC).Methods: The atherosclerotic mouse models were constructed, and the levels of PTEN in atherosclerotic tissues were detected by Real-time,PCR and Western blot;Rat VEC was treated with different concentrations of ox-LDL,cell proliferation activity was detected by MTT.VEC was transfected with PTEN overexpression vector (pSicoR-PTEN),processing cells with ox-LDL,the levels of PTEN was detected by Real-time,PCR and Western blot,cell proliferation was detected by MTT,apoptosis was detected by flow cytometry,the levels of p-STAT3,STAT3 and Cleaved Caspase-3 were detected by Western blot.Results:The level of PTEN in atherosclerotic tissue was lower than that in normal arterial tissue (P<0.05).The survival rate of VEC decreased obviously after treatment with different concentrations of ox-LDL, and the cell survival rate decreased with the increase of ox-LDL concentration.The expression of PTEN decreased in VEC after ox-LDL action, transfection of pSicoR-PTEN could increase the expression level of PTEN in VEC.The apoptotic rate of VEC increased after ox-LDL treatment,elevated levels of Cleaved Caspase-3 in cells,the level of p-STAT3 decreased,compared with normal VEC,and the difference was statistically significant (P<0.05).After transfection of pSicoR-PTEN,the survival rate and p-STAT3 level of VEC were significantly increased after ox-LDL treatment,but the apoptosis rate and the level of Cleaved Caspase-3 were significantly decreased,compared with the cells treated with pure ox-LDL,the difference was statistically significant (P<0.05).Conclusion:Downregulation of PTEN expression in atherosclerosis,PTEN inhibits the proliferation and apoptosis of VEC by ox-LDL,the mechanism of action may be related to the activation of STAT3 signaling pathway.