铜暴露下赤子爱胜蚓（Eisenia foetida）活体基因的损伤研究

通过碱性单细胞凝胶电泳法研究了Cu2+暴露剂量对赤子爱胜蚓(Eiseniafoetida)活体基因损伤的动态影响.结果显示:不添加Cu2+的对照组和添加Cu2+的处理组蚯蚓体腔细胞尾部DNA含量和尾长均呈非正态分布(p<0.05);在暴露72h时,125mg·L-1Cu2+处理组尾部DNA含量值最大,为41.44%,100mg·L-1Cu2+处理组尾长值最大,为33.79μm;随着Cu2+暴露剂量的增加,尾部DNA含量和尾长损伤频率增加;对照组和处理组的尾部DNA含量和尾长之间均存在显著性差异(p<0.05),Spearman非参数相关分析表明,尾部DNA百分含量和尾长之间呈显著相关(p<0.01,n=21),Cu2+暴露浓度与尾部DNA百分含量、尾长具有良好的剂量-构效关系(p<0.01).在125mg·L-1Cu2+浓度下暴露72h时蚯蚓的基因损伤程度达到最大,损伤程度为3级.可见,蚯蚓DNA生物标志物是重金属污染基因毒理诊断的重要指标,碱性SCGE试验是检测Cu2+暴露对赤子爱胜蚓活体基因损伤的有效手段.

Detection of DNA Damage in Earthworm (Eisenia foetida )in Vivo Exposure to Copper Ion

This paper studied the dynamic effects of doses of exposed to copper ion on coelomecytes in earthworm Eisenia foetida by alkaline single cell gel electrophoresis assay. The results showed that the data of both tail DNA percent and tail length in control experiment without Cu2+ and treatments with Cu2+ are non-normal distribution by Lilliefors test(p < 0.05). 72h after exposure, the maximum of tail DNA percent was 41.44% in the treatment with 125mg·L-1 Cu2+, and the maximum of tail length was 33.79μm in the treatment with 100mg·L-1 Cu2+. The frequencies of DNA damage of coelomecytes in the earthworm exposed to different concentrations of Cu2+ increased by box-plot tests. The data of DNA damage did not show normal distribution. Therefore, the nonparametric(Mann Whitney U and Two-Sample Kolmogorov-Smirnov)test was applied for the data from alkaline SCGE assay. There were statistically significant differences between the control and treatments in both tail DNA percent and tail length(p < 0.05). The significant dose-effect relationships were found among Cu2+ concentration, tail DNA percent and tail length(p < 0.01, n = 21)on Spearman non parameter analysis basis. The alkaline single cell gel electrophoresis is a robust tool to analyze DNA damage of Eisenia foetida in vitro, and DNA biomarker of earthworm by alkaline SCGE assay may have important application merits in genotoxicity diagnose and biomonitoring of heavy metal polluted environment.