杀虫剂三唑磷对沼水蛙（Hylarana guentheri）蝌蚪的遗传毒性研究

采用微核试验和单细胞凝胶电泳技术(彗星试验)检测了不同浓度(0、0.2、0.4、1.2、2.0、2.8mg·L-1)的三唑磷溶液对沼水蛙蝌蚪遗传毒性的影响.结果表明,当三唑磷染毒24h(≥1.2mg·L-1)及72h(≥0.2mg·L-1)后,蝌蚪微核率和核异常率比对照组均有极显著的提高.在同一时间下,随着三唑磷浓度的增大,蝌蚪微核率和核异常率总体上随之增加;在同一浓度下,随着染毒时间的增加,低浓度组(≤0.4mg·L-1)微核率出现逐渐升高趋势;高浓度组(≥1.2mg·L-1)微核率则先增加后降低.染毒24h后,彗星试验的各项指标Tail Length、Comet Length、Tail Moment和Olive Tail Moment均随三唑磷浓度的增加而增加,并呈现极显著的剂量-效应关系.当三唑磷浓度达到0.2mg·L-1时,与对照组相比,DNA总体损伤水平(Comet Assay Tail Factor)显著提高.实验表明三唑磷对蛙类蝌蚪会造成一定的遗传损伤,微核试验和彗星试验在检测污染物对蝌蚪的遗传毒性方面具有较大的应用价值.

Genotoxicity of the Pesticide Triazophos to Hylarana guentheri Tadpoles

The genotoxicity effects of different doses of triazophos on Hylarana guentheri tadpoles were evaluated by micronucleus test and single cell gel electrophoresis (SCGE, Comet assay). Results showed that exposure to triazophos at the doses as low as 0.2mg·L -1 for 72h and 1.2mg·L -1 for 24h resulted in strong significant increases in micronucleus frequency and nuclear anomalies frequency in the tadpoles. When the exposure time was fixed, the frequencies of micronucleus and nuclear anomalies increased with the increase of triazophos concentrations. When the concentration was fixed, the micronucleus frequencies increased with exposure time in groups treated with lower concentration of triazophos(≤ 0.4mg·L-1) while in groups treated with higher concentration of triazophos (≥1.2mg·L-1), the micronucleus frequencies first increased and then decreased. The results of the comet assay showed that after exposure to triazophos solution for 24h, the indices of the comet assay, such as Tail Length, Comet Length, Tail Moment, and Olive Tail Moment, increased significantly with the increase of triazophos concentrations, There were strong linear correlations between these indices and the concentrations of triazophos. Triazophos at concentration as low as 0.2mg·L-1 resulted in significant increases in Comet Assay Tail Factor of DNA damage in the tadpoles, compared with the control group. The results of this study indicated that triazophos could cause DNA damage in amphibian's tadpoles in a dose -dependent manner, and that the micronucleus assay and the Comet assay may be useful tools for measuring genotoxicity in tadpoles exposed to pollutants.