焦炉逸散物和汽车尾气有机提取物对人肝癌细胞的遗传毒性作用

目的: 探讨焦炉逸散物和汽车尾气有机提取物对人肝癌HepG2细胞的遗传毒性作用。方法:不同浓度的焦炉逸散物有机提取物(0.2、1.1、5.5、28、138和688 μg/L)和汽车尾气有机提取物(0.006、0.06、0.6、6.2、63和626.3 ng/L)染毒HepG2细胞24 h后,采用单细胞凝胶电泳实验和双微核实验分别测定细胞存活率、Olive尾矩、尾部DNA百分含量、尾长、微核率、核质桥率和核芽率。结果:焦炉逸散物和汽车尾气有机提取物染毒后,细胞Olive尾矩、尾部DNA含量和尾长均随着染毒剂量的增加而逐渐增加,与对照组相比,除0.006 ng/L汽车尾气有机提取物组的Olive尾矩外,差异均具有统计学意义(P<0.05)。焦炉逸散物有机提取物染毒后,HepG2细胞的微核率和核质桥率明显高于对照组(P<0.05),且均在5.5 μg/L时达到最高值,分别为对照组的3.6和2.5倍。核芽率随着焦炉逸散物有机提取物浓度的增加而逐渐增加,且在最高染毒浓度时为对照组的2.3倍。与对照组相比,0.6~626.3 ng/L汽车尾气有机提取物染毒后细胞的微核率和核质桥率均显著增加(P<0.01),63和626.3 ng/L汽车尾气有机提取物作用后,细胞核芽率显著增加(P<0.05)。结论:焦炉逸散物和汽车尾气有机提取物均可诱导HepG2细胞内的DNA和染色体损伤,单细胞凝胶电泳实验可作为低浓度环境复合污染物遗传毒性的快速评估方法。

Genotoxic effects of organic extracts from coke oven emissions and motor vehicle exhausts on HepG2 cells

OBJECTIVE: To investigate the genotoxic effects of extractable organic matter (EOM) from coke oven emissions (COEs) and motor vehicle exhausts on human hepatoma HepG2 cells. METHODS: After treated with different concentrations of coke oven- and traffic-EOMs,the genotoxic damage in HepG2 cells were evaluated by comet assay and cytokinesis-block micronucleus cytome assay. RESULTS: Significant dose-dependent increases in Olive tail moment, tail DNA (%),and tail length were observed in both coke oven- and traffic-EOMs treated HepG2 cells,except for the Olive tail moment in 0.006 ng/L traffic-EOMs treated group. The micronuclei and nucleoplasmic bridges frequencies induced by 5.5 μg/L of coke oven EOM increased to a maximum of 3.6 and 2.5 folds,respectively. Coke oven EOM led to a significant increase in nuclear buds frequency that progressively increased to 2.3 fold of the control level after 24 h treatment. The traffic-EOM showed appreciable increases in micronuclei and nucleoplasmic bridges frequencies over the controls across a range of concentration (0.6-626.3 ng/L). However,compared with the control group,only 63 and 626.3 ng/L traffic-EOM led to significant increases in nuclear buds frequency in HepG2 cells. CONCLUSION: Both the coke oven- and traffic-EOMs could induce DNA strand breaks and genomic instability in the metabolically competent HepG2 cells. The comet assay could provide a sensitive method for rapid screening of the genotoxicity of low concentrations of environmental complex mixtures.