Effects of melatonin on changes in cognitive performances and brain malondialdehyde concentration induced by sub-chronic coadministration of chlorpyrifos and cypermethrin in male Wister rats

Objective:To evaluate the ameliorative effect of melatonin on sub-chronic chlorpyrifos(CPF)and cypermethrin(CYP)-evoked cognitive changes in male Wistar rats.Methods:Fifty adult male Wistar rats,divided into five groups of ten rats each,were used for the study.GroupsⅠandⅡwere given distilled water and soya oil(2 ml/kg)respectively.GroupⅢwas administered with melatonin at 0.5 mg/kg only.GroupⅣwas administered with CPF[7.96 mg/kg(1/10th LD_(50))]and CYP[29.6 mg/kg(1/10th LD_(50))].and Group V was administered with CPF[7.96 mg/kg(1/10th LD_(50)]and CYP[29.6 mg/kg(1/10th LD_(50)]30 min after melatonin(0.5 mg/kg).The regimens were administered by gavage once daily for 12 weeks.Thereafter,cognitive performances were determined and the brain was evaluated for malonaldehyde concentration.Results:CPF and CYP induced cognitive deficits and increased brain malonaldehyde concentration,which were all ameliorated by melatonin.Conclusion:Cognitive deficits elicited by CPF and CYP was mitigated by melatonin due to its antioxidant property.