| Abstrakt: |
Environmental pollution is the universal problem. Most important pollutants are the heavy metals in aquatic system because of their toxicity, accumulation and bio-magnification by aquatic organism. The present study was aimed to examine the toxicological effects of mercury (mercuric chloride, HgCl2 ) in Zebra fish. For Cytotoxic effect of mercury on Gill and Liver by histopathological study forty two fishes were divided in 7 groups, with each group consisted of six fishes. Group 1 (Normal Group) which served as control, was not administered with mercury (tested drug). However, groups 2 to 4 (Drug Toxicity Groups) were administered with mercury @ 250ìg, 500ìg and 750ìg/L, respectively for 30 days (4 week) and the same doses were administered to the fishes of groups 5, 6 and 7, respectively for 60 days (8 week). After the end of the experiments, all the fishes were sacrificed and the histopathology of gill and liver tissues were performed. At the 5th week (groups 2-4) Sections of the gill of fishes of groups 2, 3 and 4 showed necrosis, degeneration and Inflammatory cell inflammation with minimal congestion in primary gill lamellae. However, at the 9th week Section of the gills of fishes of groups 5, 6, and 7 showed necrosis of epithelial cells of secondary lamellae, degeneration and disruption of cartilaginous core and disruption of primary lamellae. On the 5th week Sections of the liver of fishes of groups 2, 3 and 4 showed congestion, vascular degeneration and mild sinusoidal congestion and necrosis in hepatocytes. On the 9th week Section of the liver of fishes of groups 5, 6 and 7 showed multifocal area of the hepatocytes necrosis. The results indicate that the toxicity of mercury is dose and time dependent, suggesting that mercury at higher dose for prolonged period causes more toxicity. [ABSTRACT FROM AUTHOR] |
