Changes in tissue oxidative stress, brain biogenic amines and acetylcholinesterase following co-exposure to lead, arsenic and mercury in rats

The present study investigated the toxic effects of individual, combined (binary and ternary) exposure to lead, arsenic and mercury on, (i) oxidative stress (ii) alterations in brain biogenic amines and (iii) tissue metals concentration. Rats were exposed to lead, arsenic and mercury either individually (30 ppm in drinking water), various binary (15 ppm each) or ternary combination (10 ppm each) for a period of 6 months. Lead + arsenic and lead + arsenic + mercury co-exposure led to a significant increase in the blood oxidative stress. Mercury + arsenic and lead + arsenic + mercury co-exposure produced a more pronounced hepatotoxicity while, lead + arsenic and lead + arsenic + mercury produced a significant increase in hepatic oxidative stress. Kidney oxidative stress and changes in brain biogenic amines were more prominent in animals exposed to three metals. Accumulation of three metals did not exhibit the pattern as in the case of oxidative stress. Exposure to two toxic metals also showed less accumulation of toxic metals suggesting possible antagonism. The present study thus provides some interesting observations on the interaction between lead, arsenic and mercury. Co-exposure to lead + arsenic + mercury led to a more pronounced increase in oxidative stress in liver and kidneys compared to other exposed groups.