Aged coconut oil with a high peroxide value induces oxidative stress and tissue damage in mercury-treated rats

Background Exposure to mercury (Hg) and the ingestion of peroxidized edible oil represent a health risk. This study evaluated the effects of peroxidized coconut oil (CO) on the liver and kidney of rats treated with Hg. Methods Male albino Wistar rats were administered HgCl2 and CO separately or as a combination for 21 days. The concentrations of glutathione (GSH) and malondialdehyde (MDA), as well as the activities of superoxide dismutase (SOD) and catalase (CAT), which were used as markers of oxidative stress were measured in the liver and kidney homogenates. The activities of gamma glutamyl transferase (γ-GT), lactate dehydrogenase (LDH) as well as the levels of bilirubin and creatinine (CREA) as markers of liver and kidney functions were analyzed in the serum. Results The level of MDA in the kidney and liver homogenates was significantly increased in the HgCl2, CO, and CO+HgCl2 groups when compared to control values (p<0.05). Liver SOD activity and GSH level were increased and CAT activity was decreased, whereas kidney GSH level and SOD activity were decreased and CAT activity was increased in the CO and CO+HgCl2 groups when compared to control values (p<0.05). The increase in CREA and bilirubin levels as well as γ-GT and LDH activities observed in the CO+HgCl2 group when compared to the control values (p<0.05) were associated with pathological changes in both tissues, and were considered to be due to oxidative stress. Conclusions In summary, peroxidized CO and Hg alone or in combination induces oxidative damage in the liver and kidney of rats.