Effect of arsenic and lead on glucose level and expression of ERK in air-breathing catfish, Heteropneustes fossilis

Heavy metal contaminations may have devastating effects on the ecological balance of the environment and diversity of aquatic organisms. Furthermore, they cause great threat to the Indian aquatic ecosystem. In this study, we analyzed the effect of arsenic (As) and lead (Pb) on the blood glucose level and their possible involvement in the mitogen-activated protein kinase (MAPK) pathway in liver and muscle tissues of Heteropneustes fossilis. The catfish, H. fossilis, were exposed to an acute (35.09 ppm As2O3 and 66.20 ppm PbCl2 for ~96 h) and chronic (LC50/20th ppm of both As2O3 and PbCl2 for ~30 d) concentration of As and Pb. Thereafter, the blood glucose level and the extracellular signal-regulated protein kinase (ERK) expression level in liver and muscle tissues of the fish were analyzed. It was found that As and Pb caused hyperglycemia in H. fossilis. Both on acute and chronic treatment with As and Pb, no significant change in p-ERK1/2 expression level was found in the muscle tissue of H. fossilis, whereas, in the liver tissue, the p-ERK1/2 expression level showed a significant increase in both acute (96 h) and chronic treatment (10 d and 30 d) of As and Pb. Therefore, it can be concluded that As and Pb could be highly toxic to the aquatic fauna, which could be a potential threat to human health as well.