Abstract

Aims: Diazinon is one of the most frequent organophosphate (Ops) insecticides that is widely used in agriculture. Some OPs are capable to produce free radicals and induce disturbance in body antioxidant systems. The aim of this study is to evaluate the effects of diazinon on antioxidant system in rat's heart. Materials & Methods: Male Wistar rats of One of Tehran medical universities were randomly divided into four 7-member groups. The control group received corn oil as diazinon solvent and three experimental groups received 30, 50 and 100 mg/kg of diazinon by intra-peritoneal injection. 24 hours after injection, the animals received ether anesthesia and heart tissue was removed. After heart tissue homogenization, superoxide dismutase (SOD), catalase (CAT), glutathione S- transferase (GST) and lactate dehydrogenase (LDH) activities, as well as glutathione (GSH) and malondialdehyde (MDA) levels were determined by biochemical methods data was analyzed by INSTAT software using one-way variance analysis and Tukey's test. Results: At doses higher than 30 mg/kg of diazinon, enhanced activities of SOD, CAT and GST were observed, while GSH level significantly decreased compared to the control group. MDA level and LDH activity increased at 100 mg/kg dose of diazinon. Conclusion: Diazinon induces the production of free radicals and oxidative stress in a dose- dependent manner. The enhanced activity of antioxidant enzymes and depleted GSH content is indicative of oxidative tissue injury and the increased MDA level is indicative peroxidation of membrane lipids of heart.