Detection of DNA damage in human lymphocytes by alkaline single cell gel electrophoresis after exposure to benzene or benzene metabolites
Detection of DNA damage in human lymphocytes by alkaline single cell gel electrophoresis after exposure to benzene or benzene metabolites
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DOI：
10.1016/s0027-5107(97)00065-1
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发表时间：
1997-06-09
影响因子：
2.3
通讯作者：
Crebelli, R
中科院分区：
文献类型：
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作者：
Andreoli, C;Leopardi, P;Crebelli, R
采用碱性单细胞凝胶电泳（Comet）法研究了职业暴露于低浓度苯（12名加油站服务员，平均苯暴露量为0.3 mg/m(3), 8 h TWA）的人外周血淋巴细胞DNA损伤的发生情况。结果显示，与未暴露的对照组相比，暴露工人淋巴细胞中的DNA损伤显著增加（p = 0.028， Mann-Whitney u检验）。以100个细胞/个体为单位计算，暴露组平均尾矩值为1.900 μ m，未暴露组为0.936 μ m。此外，暴露的受试者表现出明显的严重受损细胞过量，尾力矩为总体分布的第90百分位数（13.5 vs. 6.5%, p = 0.013， Mann-Whitney u检验）。没有发现DNA损伤程度与受试者的年龄或吸烟习惯之间的相关性。为了评估苯参与离体研究结果的合理性，进一步的实验用苯代谢物对苯二酚、苯醌和苯三醇处理来自未暴露供体的体外外周淋巴细胞。在这些实验中，所有苯代谢物对静止淋巴细胞都有显著的影响，最低有效浓度低于1 μ g/ml。相反，对苯二酚在有丝分裂原刺激淋巴细胞上的平行实验需要更大的浓度才能诱导显著的DNA损伤。添加DNA修复抑制剂胞嘧啶arabinoside （Ara-C, 1-10 μ g/ml）部分恢复了受刺激细胞对对苯二酚的敏感性，表明生长细胞对诱导的DNA损伤有活性处理。这些结果还讨论了外周淋巴细胞作为靶组织在人类暴露于遗传毒性物质的生物监测中的作用。
The alkaline single cell gel electrophoresis (Comet) assay was applied to study the occurrence of DNA damage in peripheral lymphocytes of human subjects with occupational exposure to low levels of benzene (twelve gasoline station attendants, with average benzene exposure of 0.3 mg/m(3), 8 h TWA). The results obtained show a significant excess of DNA damage in lymphocytes of exposed workers, compared to matched unexposed controls (p = 0.028, Mann-Whitney U-test). Averaged tail moment values, based on 100 cells/individual, were 1.900 mu m in the exposed and 0.936 mu m in the unexposed group. In addition, exposed subjects showed a clearcut excess of heavily damaged cells, with tail moments > 90th percentile of the overall distribution (13.5 vs. 6.5%, p = 0.013, Mann-Whitney U-test). No correlation was found between the extent of DNA damage and the ages or smoking habits of the subjects. In order to assess the plausibility of the involvement of benzene in the results of the ex vivo study, further experiments were performed treating in vitro peripheral lymphocytes from unexposed donors with benzene metabolites hydroquinone, benzoquinone and benzenetriol. In these experiments, all benzene metabolites exerted a marked effect on resting lymphocytes, the lowest effective concentrations being below 1 mu g/ml. Conversely, far greater concentrations were required for the induction of significant DNA damage in parallel experiments with hydroquinone on mitogen stimulated lymphocytes. Addition of the DNA repair inhibitor cytosine arabinoside (Ara-C, 1-10 mu g/ml) partially restored the sensitivity of stimulated cells to hydroquinone, an indication of the active processing of induced DNA lesions in growing cells. These results are discussed also in relation to the role of peripheral lymphocytes as target tissue in the biomonitoring of human exposure to genotoxic agents.