百草枯经P53介导的线粒体凋亡途径诱导人肺Ⅱ型上皮样细胞A549凋亡

Paraquat induces apoptosis in human lung type Ⅱ alveolar epithelial like cells A549 through a p53-mediated mitochondrial pathway

目的:探讨百草枯(PQ)诱导人肺Ⅱ型上皮样A549细胞凋亡过程中P53的作用及其作用机制。方法:实验分为对照组、PFT-α预处理组、PQ处理组和PFT-α预处理+PQ组。各组细胞培养24h、48h后,检测细胞凋亡、线粒体膜电位、Caspase-3/-9活性以及P53、Bax、Bcl-2蛋白表达的改变。使用P53依赖的转录抑制剂PFT-α来评价P53的作用。通过Annexin V-FITC/PI双染法检测细胞凋亡率以及Rh-123染色法检测线粒体膜电位;采用检测试剂盒测定Caspase-3和-9的活化程度;Western Blot检测P53、Bax、Bcl-2蛋白的表达。结果:与PQ处理组比较,PFT-α预处理+PQ组显著减弱了PQ诱导的细胞凋亡,抑制了线粒体膜电位的降低,降低了Caspase-3和-9的活化程度、P53蛋白的表达以及Bax/Bcl-2相对蛋白水平比例。对照组与PFT-α预处理组各方面比较差异无统计学意义。结论:PQ可通过P53介导的线粒体凋亡途径诱导A549细胞凋亡。

Objective：To explore the role of P53 and its mechanism in the process of paraquat-induced apoptosis in human type II alveolar epithelial like cells A549.Method：Four groups were included：control group,PFT-αpretreatment group,PQ treatment group and PFT-αpretreatment＋ PQ group.The role of P53 was assessed using inhibitors of P53-dependent transcription,PFT-α.The changes of apoptosis,mitochondrial membrane potential,activity of Caspase-3/-9and the expression of P53,Bax and Bcl-2were induced by culturing medium containing PQ（100μmol/L）for 24 hand 48h.Apoptosis was evaluated by Annexin V-FITC/PI double staining,and mitochondrial transmembrane potential was evaluated by rhodamine 123 fluorescent staining.The activities of Caspase-3and-9were assayed by spectrophotometric method.Western blotting was used to analyze the expression of P53,Bax and Bcl-2.Result：Compared with PQ group,PFT-αpretreatment＋ PQ group significantly attenuated PQ-induced apoptosis,inhibited mitochondrial membrane potential reduction,decreased the activation of Caspase-3and-9,down regulated the protein level of P53 and the ratio of relative protein level of Bax/Bcl-2.There was no significant difference between the control group and the PFT-αpretreatment group.Conclusion：Paraquat induces apoptosis in A549 cells through a P53-mediated mitochondrial pathway.