Samujjwal Chakraborty
Assam University, India
Title: Effects of arsenic-induced oxidative stress on cellular antioxidant homeostasis and innate immune responses in Channapunctatus Bloch.
Biography
Biography: Samujjwal Chakraborty
Abstract
Heavy metals like arsenic and lead are toxic to humans and animals. Arsenic is carcinogenic and plays its role through drinking water and by entering the food chain via the water bodies. There are numerous reports of the toxic effects of arsenic and with time, research on arsenic has only gained impetus. In this study we tried to address the immunotoxicological effects of arsenic contamination and subsequent effect of its oxidative stress-induced dysfunction of both the critical defences viz. the antioxidant mechanisms as well as innate immunity in the fish Channa punctatus Bloch. Fish were treated with sub-lethal doses of sodium arsenite solution (0.24 mg/L) for 4 days and when analysed for its effect on the intestinal macrophages, it was observed that it altered the bacterial phagocytosis and the intracellular killing activity which correlated with the decrease in the release of the antimicrobials viz, nitric oxide and myeloperoxidase and the inflammatory cytokines, thus rendering the fish prone to infections. Severe damages in terms of disarrangement and fragmentation of the mucosal epithelial lining of the intestine, as observed by transmission electron microscopy emphasizes on arsenic-induced oxidative stress. While the decrease in pro-inflammatory cytokines suggests the involvement of MAPK and NFÎºï¢ pathways in the portrayal of immune dysfunction, loss of antioxidant homeostasis could be a result of direct inhibition of enzymes by arsenic. We therefore, conclude that arsenic affects the fish C. punctatus Bloch. by suppressing its immune system and antioxidant defences due to an increase of the oxidative stress, making it more susceptible to microbial attack.