Hepatoprotective role of zinc in lead-treated, protein-deficient rats

The current study was designed to evaluate the hepatoprotective role of zinc after lead (Pb) treatment of protein-deficient (PD) rats. The animals were subjected to seven different treatment groups: G-1 (normal control, 18% protein), G-2 (protein-deficient, 8% protein), G-3 (Pb-treated, 100 mg/kg body weight of lead acetate), G-4 (Zn-treated, zinc sulfate at a dose level of 227 mg/L drinking water), G-5 (PD + Pb-treated), G-6 (PD + Zn-treated), and G-7 (PD + Pb + Zn-treated). Serum albumin levels and total serum protein contents were estimated to assess the severity of protein deficiency at the end of 8 weeks in all the treatment groups. Also, the study explored the role of zinc on antioxidative defense system enzymes in liver of protein-deficient rats subjected to lead toxicity treatment. Further, the study was extended to elucidate the levels of zinc and lead in liver tissue after different treatments of rats using positron-induced X-ray emission technique (PIXE). The current study indicated a significant change in the levels of various antioxidative enzymes and serum albumin as well as total protein contents of protein-deficient rats subjected to lead treatment. A significant increase in the levels of malondialdehyde (MDA), catalase, and glutathione peroxidase (GPx) was seen after 8 weeks of lead treatment of protein-deficient rats. On the contrary, levels of albumin, total protein content, superoxide dismutase (SOD), GSH, were found to be decreased. Interestingly, zinc supplementation has tended to normalize the altered levels of these enzymes to a significant extent. The levels of zinc in liver tissue was found to be decreased significantly in protein-deficient as well as lead-treated rats. However, hepatic zinc concentration was increased to a significant extent in protein-deficient rats supplemented with zinc when compared with protein-deficient rats. Further, the presence of lead was also observed in livers of lead-treated animals. In conclusion, the study revealed the antioxidative role of zinc in hepatotoxic conditions induced by subjecting the rats to protein-deficient diet and lead treatment.