Abstract

Neurotoxicity of individual metals is well investigated but that of metal mixture, an environmental reality, in the brain is relatively obscure. We investigated the combinatorial effect of metals (As and Pb) in brain regions such as cortex, cerebellum and hippocampus and compared the toxicity levels with individual metal exposed group. The studies were conducted to examine the alterations in SOD isoforms (SODtotal, Mn - SOD, Cu/Zn - SOD) because it is the first line of antioxidant defense and is highly efficient in protecting cells against oxidative stress by catalyzing the dismutation of superoxide radicals to form hydrogen peroxide and molecular oxygen. The results showed that metal mixture produced decrease in SOD isoforms and gene expression level in brain regions than individual metal exposure. Among the brain regions, the hippocampus showed greater decreases in Mn - SOD and Cu/Zn - SOD enzyme activities and gene expression levels than cerebellum and cortex. These effects were greater following metal mixture exposure as compared to individual metal exposure.