应用胞质分裂阻滞微核细胞组学法评价三溴乙酸的遗传毒性

目的]应用胞质分裂阻滞微核细胞组学方法cytokinesis-block micronucleus cytome（CBMN-cyt）assay]评价三溴乙酸的遗传毒性。方法]以小鼠淋巴瘤（L5178Y）细胞为受试细胞，分为2组。一组暴露于终浓度分别为0（阴性对照）、7．81、15．62、31．25、62．50、125．00、175．00、250．00μg／mL的三溴乙酸溶液24h，采用噻唑蓝比色法（MTF法）检测细胞毒性，并计算半数致死浓度（medianlethaldose，LC50）；另一组暴露于终浓度分别为0（阴性对照）、31．25、62．50、125．00、175．00μg／mL的三溴乙酸溶液24h，并设阳性对照（终浓度为0．10μg／mL丝裂霉素C），采用CBMN-cyt试验检测遗传毒性。结果]与阴性对照组相比，31．25、62．50，125．00，175．00，250．00μg／mL三澳乙酸染毒组L5178Y细胞的存活率均较低，差异有统计学意义（P〈0．05）；且随着三溴乙酸染毒浓度的升高，L5178Y细胞的存活率呈明显的下降趋势（尸〈0．01）。三溴乙酸对该细胞的LC50为135．7μg／mL。与阴性对照比较，125．00、175．00μg／mL三溴乙酸染毒L5178Y细胞的微核率均升高，各浓度三溴乙酸染毒L5178Y细胞的核质桥率也均升高，差异有统计学意义（P〈0．05）；而各浓度三溴乙酸染毒L5178Y细胞的核芽率和核分裂指数（nucleusdividedindex，NDI）无显著改变。Pearson相关分析显示，随着三溴乙酸染毒剂量的升高，L5178Y细胞的微核率、核质桥率、核芽率均呈明显的上升趋势（P〈0．01）。结论]三溴乙酸的遗传毒性，可能与染色体损伤、DNA错误修复、染色体重组或端粒末端融合损伤有关。

Evaluation on Genotoxicity of Tribromoacetic Acid by Cytokinesis-Block Micronucleus Cytome Assay

Objective ] To test the genotoxicity of tribromoacetic acid by cytokinesis-block micronucleus cytome （CBMN-cyt） assay. Methods ] Mice L5178Y lymphoma cells were treated with tribromoacetic acid at 0（negative control）, 7.81, 15.62, 31.25, 62.50, 125.00, 175.00, and 250.00 μg/mL for 24 h. The cytotoxicity was tested by tetrazolium salt colorimetric assay, and the median lethal dose （LCs0） was calculated. The cells were treated with tribromoacetic acid at 0 （negative control）, 31.25, 62.50, 125.00, and 175.00μg/mL for 24h, and plus 0.1 μg/mL mitomycin C as a positive control, and the genotoxicity was tested by CBMN-cyt assay. Results ] Compared with the negative control group, the survival rate of LS178Y lymphoma ceils in the 31.25, 62.50, 125.00, 175.00 and 250.00 μ/mL groups decreased significantly （P〈 0.05）. From the dose-effect curve, a decreasing trend for the survival rate of LS17SY lymphoma cells was found with the increasing of dosage of tribromoacetic acid （P〈 0.01）. The LCs0 of tribromoacetic acid was 135.70 μg/mL. Compared with the negative control group, the frequency of micronucleus （MN） of L5178Y lymphoma cells in the 125.00 and 175.00 μg/mL groups and the nucleoplasmic bridges （NPBs） in all treatment groups increased significantly （P〈 0.05）, but there were no differences in the frequency of nuclear buds （NBUDs） and the nuclear divided index between the treatment groups and the control group. The results of Pearson correlation test showed that along with the increasing of tribromoacetic acid treatment dosage increasing trends were found in the frequency of MN, NPBs, and NBUDs （P〈0.01）. Conclusion ] The findings by the application of CBMN-cyt assay indicate that tribromoacetic acid could induce genotoxicity, mainly including chromosome damage, DNA error-prone repair, chromosome recombination or damage of telomere fusion.