Effect of Lead on Oxidative Stress, Na+K+ATPase Activity and Mitochondrial Electron Transport Chain Activity of the Brain of Clarias batrachus L.

The present invivo study was designed to elucidate the toxic effect of lead on oxidative stress, Na⁺K⁺ATPase and mitochondrial electron transport chain activity of the brain of Clarias batrachus. The fish were exposed to 10 and 20% of the derived 96 h LC₅₀ value, 37.8 and 75.6 mg L⁻¹, respectively, and sampled on 20, 40 and 60 days. Exposure of fish brain to lead demonstrated an increased production of reactive oxygen species, increased lipid peroxidation, loss of protein thiol groups in synaptosomal fraction with the decreased activity of Na⁺K⁺ATPase, partial inactivation of mitochondrial electron transport chain activity and energy depletion. However, no change in protein carbonyl content in synaptosomal fraction was observed due to lead exposure. Concluding the results of our investigation we suggest that lead exposure induces oxidative stress in the brain of Clarias batrachus and the decline in Na⁺K⁺ATPase activity was presumeably mediated by the combined action of lipid peroxidation and deficient mitochondrial electron transport chain activity.