RESUMEN
Reactive oxygen species [ROS] have been implicated in the toxicity of various insecticides. Pyrethroids, though having the advantage of low mammalian toxicity, have been reported to produce signs of toxicity Most of these are linked to skeletal muscles. The present study tests the ability of single or repeated administration of Cypermethrin, a type II pyrethroids. to induce lipid peroxidation [LPO] in die rat brain, liver and diaphragm tissues. The study included the effect on antioxidant parameters, reduced glutathione [GSH], glutathione peroxidase [GPX], superoxide dismutase [SOD], and the protective effect of vitamin E. Single and repeated [7 days] administration of Cypermethrin [1/10 LD] induced lipid peroxidation in the rat diaphragm, while the brain and liver showed significant lipid peroxidation upon repeated administration only. This was manifested as elevation of the marker malondialdehyde [MDA]. The antioxidant defense parameter. GSH. GPX and SOD were not affected by single dose of Cypennethrin. in the rat brain or liver tissues. while, in the rat diaphragm a significant reduction in glutathione peroxidase was evident. In the rat diaphragm, repeated administration of Cypermethrin increased the level of GSH while decreased GPX activity. No significant effect was shown on the rat brain or iiver tissues. SOD activity was significantly reduced ia he diaphragm while the brain and the liver showed significant increase in the enzyme activity. Prior administration of vitamin E effectively antagonized the changes in LPO and the antioxidant parameters GSH, GPX and SOD induced by Cypennethrin. In conclusion, Cypermethrin induced LPO and an increase in the ROS. This may be linked to the mechanism underlying its insecticidal action as well as its adverse effects. Vitamin E is an effective agent to protect against the lipid peroxydative s power of Cypermethrin