Metallothionein Induced Time Dependent Histomorphometric Analysis of Clarias gariepinus Exposed to Cadmium.

Cadmium (Cd), an extremely toxic heavy metal is extensively used in modern era because of its constructive chemical and physical properties. Recently Cd contamination was estimated in India's major cities fresh water ecosystem, which may have firm impact on human health. Hence, this study was aimed to detect the time dependent effect of cadmium in fresh water fish C. gariepinus, a bioindicator species of water pollution. In a controlled environment, fishes were exposed to cadmium for different duration and analyzed for Cd accumulation. Cd induced toxicity was assessed by estimating metallothionein biomarker protein of heavy metal toxicity and histomorphometric changes in liver and kidney. Our results revealed that fish exposed to Cd induced apoptosis in fish tissues via induction of caspases and in contrast the metallothionein was also increased consistently with different doses of Cd exposure. Hence we conclude Cd induced structural damages to fishes are attributed to induction of caspases and estimating MT level in tissues can be effective biomarker to analyze the effect of acute environmental exposure to Cd.