The Protective Effect of Vitamin E in Pyrethroid-induced Oxidative Stress in Rat Tissues

Abstract

AbstractPyrethroids such as cypermethrin and fenvalerate were administered as a single dose (0.001% LD 50 ) to rats to assess their effect on oxidative stress and the antioxidant defence system in the liver, kidneys and heart tissues. Pretreatment with vitamin E, before pyrethroid treatment, was to find out whether vitamin E pretreatment would protect the rats from pyrethroid-induced oxidative stress. Lipid peroxidation (LPO) increased in the liver and kidneys in cypermethrin and/or fenvalerate treated rats; however, vitamin E pretreated rats administered pyrethroids showed a lowering in LPO. The heart tissue showed no significant change in LPO with cypermethrin or fenvalerate treatment, probably owing to hypertrophy; however, both the pesticides, when administered together, showed increased LPO. The elevated superoxide dismutase (SOD) and catalase (CAT) activities in the tissues were probably a response to the increased generation of free radicals which decreased in vitamin E pretreated rats which were administered pyrethroids. The increase in tissue glutathione (GSH) content and glutathione-S-transferase (GST) activity in pyrethroid treated rats was also lowered in vitamin E pretreated rats which were administered pyrethroids. The inhibition in acetylcholinesterase (AChE) activity was partially reversed in vitamin E pretreated rats which were administered pyrethroids. Histology showed liver necrosis in rats administered cypermethrin or fenvalerate pesticides. Vitamin E pretreatment provided more protection to the liver in cypermethrin treated rats as compared to fenvalerate treated animals as observed histologically. The results indicate that vitamin E pretreatment lowers oxidative stress in tissues and alters the antioxidant system to counteract pyrethroid-induced oxidative stress. However, the inhibition in tissue AChE activity was not fully relieved, probably because of the competitive nature of inhibition.KeywordsCypermethrinFenvalerateReactive Oxygen SpeciesLipid PeroxidationSuperoxide DismutaseCatalaseGlutathioneGlutathione-S-TRANSFERASEAcetylcholinesterase