Biochemical and histopathological changes induced by different time intervals of methomyl treatment in mice liver

The present study was designed to evaluate the toxic effects induced by different time intervals of methomyl exposure on liver antioxidant defense system, oxidative stress, liver function biomarkers and histopathology in CD-1 mice. Ten male mice per group were assigned to one of four treatment groups. Group one served as control while group 2, 3 and 4 were orally treated with one mg methomyl/kg BW for 10, 20 and 30 days, respectively. Results obtained showed that methomyl significantly induced TBARS and decreased the activity of antioxidant enzymes, glutathione S-transferase, superoxide dismutase and catalase and the levels of reduced glutathione in mice liver. Aminotransferases and alkaline phosphatase activities were significantly decreased in liver due to methomyl administration, while the activities of these enzymes were significantly increased in serum. In addition, liver lactate dehydrogenase activity was significantly increased. On the contrary, methomyl treatment caused a significant decrease in liver acid phosphatase. The histology of mice liver treated with methomyl for 10, 20 and 30 days of duration showed dilation of central vein, sinusoids between hypertrophied hepatocytes and nuclear degeneration with mononuclear cell infiltration. In conclusion, exposure to methomyl induced toxicity and oxidative stress in mice liver via free radicals mechanism. Also, methomyl might have affected cell metabolism, cell membrane permeability and the detoxification system in liver.