汽油尾气诱导的细胞毒性效应涉及氧化应激

目的探讨氧化应激在汽油尾气三相有机提取物(EGE)细胞毒效应中的作用。方法采用MTT比色试验检测汽油尾气对A549细胞的细胞毒性效应,同时用2’,7’-二氯双氢荧光素双乙酸酯法测定汽油尾气对细胞活性氧(ROS)生成的影响;此外,用不同浓度谷胱甘肽(GSH)预处理细胞2h后再观察汽油尾气细胞毒性效应的变化。结果当EGE浓度>3.9ml/ml时,细胞存活率均显著降低(P<0.05),并且具有良好的剂量-反应关系(r=-0.81,P<0.01)。当汽油尾气浓度为31.3ml/ml和62.3ml/ml时,A549细胞单位面积的荧光强度分别为(125.0±19.2)和(168.9±16.9),与对照组(8.5±1.4)比,细胞单位面积荧光强度显著增加(P<0.05)。采用0.5和1.0mmol/L谷胱甘肽预处理细胞后,处理组细胞存活率显著高于未处理的对照组(P<0.05)。结论氧化应激可能是汽油尾气细胞毒性的毒作用机制之一。

Cytotoxicity induced by gasoline engine exhausts associated with oxidative stress

Objective To evaluate the relationship between cytotoxic effects of the extracts of condensate,particulates and semivolatile organic compounds from gasoline engine exhausts(EGE) and oxidative stress.Methods After A549 cells were treated with various concentrations of EGE for 2h,and cell viabilities were detected induced by EGE were examinedby MTT assay.Meanwhile,the reactive oxygen species(ROS) in A549 cells induced by EGE were examined,2',7'-dichlorodihy-drofluorescin diacetate(DCFH-DA) was used to catch ROS and its level measured by value of pixel fluorescence intensity.Furthermore,A549 cells pretreated with different concentrations of glutathione(GSH) were exposed to various concentrations of EGE for 2h,and then cell viabilities were examined.Results Viabilities of A549 cells significantly decreased in comparison to the solvent group when the concentrations of EGE were more than 3.9ml/ml(P<0.05).There were a dose-response relationships between the viabilities and the concentration of EGE(r=-0.81,P<0.01).At the concentrations of 31.3ml/ml and 62.5ml/ml,the values of pixel fluorescence intensity were(125.0±19.2)and(168.9±16.9),which were significantly higher than those of control(8.5±1.4).In addition,the viabilities of cells pretreated with GSH gradually increased with the increases of the concentrations of GSH.There were also a significant difference between the pretreated and non-pretreated group at the concentrations of 0.5mmol/L and 1.0mmol/L.Conclusion Oxidative stress could be one of the mechanisms of cytotoxic effects of EGE.