Toxic effects of methamidophos on paraoxonase 1 activity and on rat kidney and liver and ameliorating effects of alpha‐tocopherol

The role of alpha‐tocopherol on nephrotoxicity and hepatotoxicity induced by methamidophos (MT) was investigated in wistar rats. Animals were given via gavage, for four weeks, a low dose of MT (MT1), a high dose of MT (MT2), vitamin E (200 mg/kg of bw) or both MT2 plus vitamin E (Vit E) and control group was given distillate water. MT treatment resulted in a significant decrease in the body weight of MT2‐treated group. Moreover, MT‐treated groups had significantly lower butyrylcholinesterase (p < 0.01) and paraoxonase 1 (PON1) activities compared with the control group (p < 0.05). However, MT2‐treated group had significantly higher alkaline phosphatase activity compared with untreated rats (p < 0.05). Both MT‐treated groups had significantly higher urea (p < 0.01) and uric acid levels (p < 0.05) compared with the control group. However, significant low uric acid level (p < 0.05) was noted in MT2 plus vit E‐treated rats compared with MT2‐treated group. Histopathological changes in organ tissues were observed in both MT‐treated groups and MT2 plus vit E‐treated rats. However, the damage was reduced in MT2 plus vit E‐treated rats. Therefore, this study deduces that alpha‐tocopherol administration may ameliorate the adverse effects of subacute exposure to MT on rat liver and kidney and this antioxidant can protect PON1 from oxidative stress induced by this organophosphorus pesticide. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 842–854, 2016.