AMELIORATIVE EFFECT OF SELENIUM AS ANTIOXIDANT ON FLUORIDE TOXICITY INDUCED OXIDATIVE DEGENERATIVE CHANGES ON CARDIAC TISSUE

Abstract

Fluorosis is an endemic disease caused due to the chronic intake of fluoride, which alters body physiology, especially antioxidant status and lipid metabolism. There are reports which suggests that degenerative changes occur in cardiovascular system due to fluoride ingestion, may be caused due to oxidative stress. Selenium is a component of the antioxidant enzymes glutathione peroxidase and thioredoxin reductase has an antioxidant property. Hence, the present study was designed to evaluate the antioxidant effect of selenium and its ameliorative action on cardiac tissue damage of fluorotic rats. Eighteen male adult Wister rats were divided into 3 groups, 6 rats in each group. One group served as control and the other two groups as experimental control & experimental group. Both the experimental groups were given 200ppm of fluoride drinking water for 100days and only experiment group received supplement of selenium (5mg/kg body weight) which was given orally as   single dose daily for another 20days and both the groups were continued to receive fluorinated drinking water during the extended period also. The control group rats received ordinary drinking water throughout the experimental period. At the end of the experimental period, the rats were sacrificed as per ethical guidelines and the cardiac tissues were harvested for histological & biochemical studies. One ml of blood was collected from  retro-orbital plexuses before animals were sacrificed. Fluoride treatment significantly decreased the body weight, increased the oxidative stress, decreased glutathione levels, increased malondialdehyde levels in cardiac tissue homogenate and increased level of serum AST was observed in fluoride ingested rats. The histological scrutiny of the cardiac tissue of these rats showed degenerative changes. The result of experimental group which received oral supplementation of selenium for 20days showed the opposite of only fluoride ingested experimental control group. Here, the MDA & serum AST levels were decreased whereas GSH level was increased. These biochemical changes were supported by histological observation of the experimental rats where, the cytoarchitecture of cardiac tissues showed near normal picture. The result may suggest that dietary supplementation of selenium to animals and humans living in fluoride endemic zones may probably reduce the risk of cardiac tissue damage.