PM2.5对血管内皮细胞氧化应激和凋亡的影响及机制

Oxidative stress and apoptosis in endothelial cells exposed to PM2.5

目的:从大气细颗粒物PM2.5对血管内皮细胞氧化应激和凋亡的影响,研究PM2.5对血管内皮细胞的毒性。方法:体外培养血管内皮细胞株EA.hy926,用不同浓度的PM2.5染毒24 h后,用CCK-8法测细胞的活性,用DCFH-DA荧光标记法检测细胞内氧自由基生成情况,用流式细胞术检测细胞凋亡率,然后用Western blot法检测凋亡相关蛋白细胞色素C、cleaved caspase-9和cleaved caspase-3的表达变化。结果:CCK-8法结果显示PM2.5对血管内皮细胞有明显的毒性,在浓度大于25 mg/L时可使EA.hy926细胞活性显著下降;PM2.5染毒24 h后可见DCFH-DA荧光染色增强,说明细胞内有大量的氧自由基形成;流式细胞术和Western blot检测证实PM2.5可以通过上调细胞色素C表达和活化cleaved caspase-9和cleaved caspase-3而诱导EA.hy926细胞凋亡。此外,用N-乙酰半胱氨酸抑制氧自由基生成可以抑制血管内皮细胞凋亡,提示PM2.5引起的细胞凋亡与氧化应激有关。结论:PM2.5可导致血管内皮细胞氧化应激水平增强和凋亡增加,这可能是其影响心血管系统功能的机制之一。

AIM：To study the toxicity of PM2.5 in the endothelial cells by investigating the induction of reactive oxygen species （ROS） and apoptosis in EA.hy926 cells exposed to PM2.5.METHODS： The endothelial cell line EA. hy926 was cultured in vitro and exposed to PM2.5 at different concentrations for 24 h.The cell viability was measured by CCK-8 assay and the generation of intracellular ROS was stained with DCFH-DA.The cell apoptosis was analyzed by flow cy-tometry with Annexin V-FITC/PI staining, and the protein levels of cytochrome C , caspase 9 and caspase 3 was detected by Western blot.RESULTS：After the treatment with PM2.5, the viability of the EA.hy926 cells was decreased markedly and the production of ROS was increased significantly .PM2.5 exposure upregulated the expression of cytoplasm cytochrome C and activated caspase-9 and caspase-3, resulting in the increase of the cell apoptosis significantly .The ROS generation was direct-ly involved in PM2.5-mediated endothelial cell apoptosis as N-acetyl-L-cysteine pretreatment abolished both ROS production and cell apoptosis induced by PM 2.5.CONCLUSION：PM2.5 induces oxidative stress and apoptosis in the vascular endo-thelial cells, which may be one of the mechanisms that PM2.5 influences the function of cardiovascular system .