研究有机磷类农药毒死蜱和对硫磷、氨基甲酸酯类农药克百威和残杀威单独及联合染毒大鼠嗜铬细胞瘤株(PC12细胞)所致的DNA损伤情况及联合作用模式.分别以0μmol·L-1、50μmol·L-1、100μmol·L-1、200μmol·L-1、400μmol·L-1的有机磷农药毒死蜱、对硫磷与0μmol·L-1、25μmol·L-1、50μmol·L-1、100μmol·L-1、200μmol·L-1的氨基甲酸酯类农药克百威、残杀威单独及两两联合染毒PC12细胞12 h后进行彗星实验,采用彗尾长度、尾部DNA百分含量、尾矩3个指标来衡量DNA损伤程度.结果表明:毒死蜱、克百威、对硫磷、残杀威染毒PC12细胞12 h后,细胞出现拖尾,呈现典型的彗星图像.染毒后PC12细胞彗尾长度、尾部DNA百分含量、尾矩较对照组显著增加,差异有统计学意义(P<0.01).析因分析表明,无论低剂量联合还是高剂量联合,毒死蜱与克百威、对硫磷与残杀威均有交互作用(P<0.01),作用模式为协同作用.以上结果提示,有机磷及氨基甲酸酯类农药单独及联合作用均可引起PC12细胞DNA损伤,联合作用后损伤程度要高于单独作用,且低剂量和高剂量联合时均存在交互作用,作用模式为协同作用.%The paper aims to evaluate invitroDNA damage of PC12 cells induced by pesticides chlorpyrifos, para-thion, carbofuran and propoxur alone or jointly after 12-hour exposure. The concentrations of pesticides chlorpyri-fos and parathion applied were 0, 50, 100, 200 and 400 μmol·L-1 , respectively. The concentrations of pesticides carbofuran and propoxur applied were 0, 25, 50, 100 and 200μmol·L-1, respectively. PC12 cells were first exposed to these pesticides alone or jointly for 12 h. The Comet assay was then used to evaluate the degree of DNA damage via measuring the length of comet tails, DNA contents in comet tails and tail moments. The PC12 cells showed typi-cal images with tailing after being exposed for 12-hour to chlorpyrifos, carbofuran, parathion and propoxur. The tail length, tail DNA percentage and tail moments increased significantly comparing to the controls, and the difference is significant in statistics (P<0.01);factor analysis showed that chlorpyrifos and carbofuran, parathion and propoxur interacted (P<0.01) in both low dose and high dose of combinations, and the synergistic effect was observed. Therefore, the DNA damage of PC12 cell can be induced by both organophosphorus and carbamate pesticides. The extents of DNA damage induced by a joint exposure of two pesticides were more significant than that induced by an exposure of a single pesticide. Joint exposure of two pesticides demonstrates a synergistic effect.
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