Abstract The present research was planned to analyze the toxic effects of thimerosal on rat liver. Mercury and mercury compounds are universally known toxicants for animals and humans. Thimerosal is widely used in the vaccines as a preservative which contains 49.6% mercury. Twenty-four adult male albino rats were distributed into four groups (n=6). The first group was considered as a control group. While, second, third and fourth groups were intoxicated with 0.5, 10 and 50 µg/kg thimerosal (i.m.) respectively. After 30 days, rats were slaughtered to analyze the liver tissues. The results of the experiment exposed that thimerosal instigated significant (p<0.05) increase in alanine transaminase (ALT), alkaline phosphatase (ALP) and aminotransferase (AST) levels. Catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) activities and Glutathione (GSH) and protein levels were significantly (p<0.05) reduced. Furthermore, significant increases in Hydrogen peroxide (H2O2), thiobarbituric acid reactive substances (TBARS) level and DNA damage was observed. Histopathological study revealed severe damages, e.g. fatty alterations, deterioration of lobular structure and degeneration of nuclei in hepatic tissues of thimerosal treated rats. Results of present investigation revealed that thimerosal induces hepatotoxicity at different levels.

ABSTRACT: The present study was aimed to evaluate the effect of heavy metals on an important tissue of two fish species Cyprinus carpio and Wallago attu, sampled from the Indus river, Mianwali District, Pakistan. The concentration of selected heavy metals Fe, Cr, Cu, and in gills, muscles, kidney and liver was compared with an International standard of food fish. The overall metal concentrations among different weight categories in C. carpio were in the order of Fe > Cu > Cr >. In W. attu the overall accumulation of these metals were, in order of Fe > Cu > Cr > Pb The order of accumulation of metals in gills and muscle of C. carpio was Fe > Cr > Pb > Cu; kidney and muscles of W. attu was Fe > Cr > Cu > Pb; liver Fe > Cu > Cr > Pb. An increasing trend of concentration of iron, copper, chromium and lead occurred with an increase in weight of C. carpio and W. attu. There was a significant difference in the accumulation of heavy metals in different organs of both species (p<0.01). All studied heavy metals except Cr were within permissible limits described by various international agencies like WHO, FAO and FEPA in edible tissues of C. carpio and W. attu.

The aim of this work was to study the effects of sub-lethal exposure of lead acetate on the histopathology of the gills, liver, kidney and muscle and its accumulation in these organs of Clarias gariepinus. Results showed that lead accumulation in the tissues of C. gariepinus was dependent on the exposure period and lead concentration. Gills and liver were the predominant storage tissue and the order of accumulation in tissues was gill > liver > kidney > muscle. Some structural changes were observed in different organs, especially in the gills of the fishes exposed to lead acetate. Epithelial hypertrophy and epithelial lifting were apparent in the gills of exposed fishes. The degeneration of cytoplasm and secondary lamellae was also observed. Necrosis of hepatocytes was apparent. Glomerular expansion and gaps between the muscular bundles were found in the fishes exposed to lead acetate.