The Comparison of the Effect of Diazinon and Paraoxon on Biomarkers of Oxidative Stress in Rat Serum

Background: Diazinon and paraoxon are a group of pesticide organophosphates which are widely used in agriculture. Some organophosphates increase the production of free radicals. This study aims to compare the effects of diazinon and paraoxon on biomarkers of oxidative stress in rat serum. Materials and Methods : This experimental study was performed in 2010 in Baqiyatallah (a.s) University of Medical Sciences. 49 male Wistar rats were randomly divided into 7 groups: the control group was given corn oil as a solvent of diazinon and paraoxon and the other six groups were given diazinon at doses 30, 50 and 100 mg/kg and paraoxon at doses 0.3, 0.7 and 1 mg/kg intraperitoneally. 24 hours after the injection, blood was collected by cardiac puncture and serum was prepared. Then, the activities of butrylcholinesterase enzyme (BChE), superoxide dismutase (SOD), catalase (CAT) and lactate dehydrogenase (LDH) and glutathione level (GSH) were measured by chemical methods. Results: The decreased SOD and CAT activities and GSH level after administration of Diazinon (more than 30 mg/kg) and paraoxon (more than 0.3 mg/kg) is significant compared to control group, whereas the activity of LDH enzyme significantly increases. The decreased BChE activity is not significant compared to control group. Conclusion: Diazinon and paraoxon induce the production of free radicals and oxidative stress in a dose-dependent manner. The decreased activity of antioxidant enzymes and depleted GSH content probably represent the antioxidant defense system failure against the toxic actions of free radicals and oxidative tissue damage. Paraoxon has more severe effects than diazinon.