Ameliorative effects of melatonin on brain biochemical changes induced by subchronic co-administration of chlorpyrifos and cypermethrin in male Wistar rats

The present study was aimed at evaluating the ameliorative effects of melatonin on chlorpyrifos and cypermethrin induced brain biochemical changes involving malonadialdehyde (MDA), catalase, superoxide dismutase, glutathione peroxidise and acetyl cholinesterase in male Wistar rats. The fifty adult male Wistar rats used for this study were divided into 5 groups of 10 animals each. Group I was administered distilled water, group II was given soya oil (2 ml/kg), group III was given melatonin (0.5 mg/kg), group IV was given chlorpyrifos (7.94 mg/kg - 1/10th LD50) and cypermethrin (29.6 mg/kg - 1/10th LD50), and group V was pretreated with  melatonin (0.5 mg/kg) and then 30 min later,  chlorpyrifos (7.94 mg/kg-1/10th LD50) and cypermethrin (29.6 mg/kg - 1/10th LD50). The regimens were administered by gavage once daily for a period of 12 weeks. Increased MDA concentrations, decreased catalase, superoxide dismutase, glutathione peroxidise, and acetylcholinesterase activities were recorded in the group IV, however, these changes were ameliorated by melatonin. Therefore, it was concluded that melatonin mitigated chlorpyrifos and cypermethrin induced brain biochemical changes due to its antioxidant properties.   Key words: Chlorpyrifos, cypermethrin, melatonin, biochemical changes, oxidative stress.