毒死蜱和乐果联合染毒对大鼠肝脏抗氧化酶活性的影响

Objective To study the combined toxic effect of chorpyriphos and dimethoate on the antioxidant enzymes and lipid peroxidation products of the female rats, including superoxide dismutase, catalase and malondialdehyde. To acquire a further understanding of the mechanism of how organophosphorus pesticides affect the human body. Methods Chorpyriphos and dimethoate used in the experiment were both at the dose of NOAEL and 1/50LD50. The adult female SD rats were randomly divided into 5 groups (including a control group and four treated groups) by weight, with 10 rats in every dose group. Various daily doses of chorpyriphos+dimethoate (0.03+1.2, 0.03+6.5, 2.7+1.2, 2.7+6.5mg/(kgobw)/d) were given to rats by gastric gavage for 30 successive days. 2×2 factorial analysis was used in the experiment. Results The experiment showed the combination of chorpyriphos and dimethoate might improve the activity of SOD and CAT and the concentration of MDA, while didn't affect the weight and liver coefficient of experiment animals. As the dose of chorpyriphos and dimethoate increased, the improvement of antioxidant enzymes was larger. It is worth noting that the lowest dose of chorpyriphos and dimethoate didn't change the activity of SOD and CAT but decreased the concentration of MDA, demonstrating the potential existense of hormesis effect and the limit of antioxidant enzymes on indicating organophosphorus pesticides exposure. Factorial analysis showed no interaction between chorpyriphos and dimethoate on superoxide dismutase, malondialdehyde and catalase. The joint action was characterized as an additive effect. Conclusion The combination of chorpyriphos and dimethoate might increase the activity of SOD and CAT and the concentration of MDA; the joint action of chorpyriphos and dimethoate on superoxide dismutase, malondialdehyde and catalase was additive effect. At the lowest dose of chorpyriphos and dimethoate, the activity of SOD and CAT didn't increase as expected, showing that superoxide dismutase and catalase may not be used as sensitive indicator enzymes of low-dose organophosphorus pesticides exposure.