甲醛和乙苯联合染毒对小鼠脑组织DNA的损伤

Toxicity of Combined Exposure to Formaldehyde and Ethylbenzene on DNA Damage in Brain Cells of Mice

[目的]探讨不同浓度甲醛和乙苯单独及联合染毒对小鼠脑组织DNA的损伤作用,分析其联合作用的类型。[方法]采用4×4析因设计,利用单细胞凝胶电泳实验方法,研究甲醛(0、0.2、2.0、20.0mg/kg)和乙苯(0、50、250、500mg/kg)单独以及二者联合染毒后小鼠脑组织DNA的损伤情况。[结果]甲醛和乙苯单独及联合染毒组小鼠脑细胞彗星拖尾率、尾部DNA含量和尾矩均高于对照组(P<0.05);彗星细胞拖尾率随染毒剂量的增加而增大,高剂量联合组小鼠的拖尾率高于其他各组(P<0.05);尾部DNA含量和尾矩均随乙苯剂量的增加而增大;低、中剂量染毒组的尾部DNA含量和尾矩随着甲醛剂量的增加而增大,但高剂量组减小;二者之间存在交互作用(P<0.05)。[结论]甲醛和乙苯均可对小鼠脑组织造成DNA的损伤,联合染毒组的脑组织损伤程度重于单独染毒组,二者的联合效应表现为协同作用。

[ Objective ] To explore the toxicity of single or combined exposure to formaldehyde and ethylbenzene on DNA damage in brain ce]ls of mice and to analyze the type of joint toxic effect. [ Methods ]Based on a 4 x 4 factorial experiment design, single cell gel electrophoresis （SCGE） technique was used to investigate DNA damage in mice brain cells exposed to formaldehyde （0, 0.2, 2.0, and 20.0mg/kg）, ethylbenzene （0, 50, 250, and 500mg/kg）, and both. [ Results ] Compared with the control group, the comet cells ratio, the percentage of tail DNA, and the Olive tail moment in all exposure groups increased significantly （P 〈 0.05）. The comet cells ratio showed a significant upward tendency with increasing chemicals＇ doses, and was significantly elevated in the group treated with high-dose mixture compared with the other exposure groups （P〈 0.05）. The percentage of tail DNA and the Olive tail moment were also increased as the dose of ethylbenzene or formaldehyde increased, but not in the group treated with high dose of formaldehyde. An interaction between toxic effects of formaldehyde and ethylbenzene was identified （P〈 0.05）. [ Conclusion ] Formaldehyde and ethlybenzene could cause DNA damage in mice brain cells and the joint exposure show severer effect than either single exposure. The joint toxic effect on DNA damage appears to be synergistic.