Effects of acute dimethoate administration on antioxidant status of liver and brain of experimental rats

Organophosphorus compounds may induce oxidative stress leading to generation of free radicals and alterations in antioxidant and scavengers of oxygen free radicals. The present study demonstrates effect of acute exposure of dimethoate in causation of oxidative stress in male Wistar rats. Dimethoate was administered orally at doses 45, 75 and 90 mg/kg of body weight on the basis of LD(50) for 24 h. After administration of doses, the liver and brain homogenates were analyzed for various parameters of oxidative stress. The results indicated an increase in hepatic cytochrome P450, lipid peroxidation, catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase in liver and brain at 90 and 75 mg/kg doses. There were no significant changes in the levels of glucose-6-phosphate dehydrogenase activity in both liver and brain. Similarly, there were no significant changes in hepatic glutathione and glutathione-S-transferase activities. However, there was a significant increase in glutathione and glutathione-S-transferase in brain at 90 mg/kg dose only. Erythrocyte acetylcholinesterase was inhibited at all doses used. Dose-dependent histopathological changes, observed in both liver and brain, are also described.