ABSTRACT
Tetrachloroethane [TTCE] is one of the chlorinated hydrocarbons used as an industrial solvent. It is also claimed to be an environmental pollutant that may have multisystem detrimental effects. This study demonstrates some of the biochemical and histological toxic effects of TTCE on the rat liver, kidney and lung. It also estimates the effect of this substance on the DNA content of the cells. The study also evaluates and compares the protective role of the nutritional supplements zinc and silibinin on the observed toxic effects. 60 adult Sprague Dawly rats were used for the experiment divided equally into six groups: a negative control group, a group receiving TTCE, a group receiving zinc and a group receiving silibinin. In addition there were groups of combined treatment of TTCE plus zinc and TTCE plus silibinin. TTCE was given at a dose of 0.01ml/kg, zinc was given at a dose of 30mg/kg and silibinin was given at a dose of 200mg/kg. The duration of the experinent was 4 weeks then biochemical analysis of liver and kidney functions as well as zinc level estimation were performed. Histopathological examination of the liver and lung was done including the estimation of the content of the nuclear DNA. The study revealed the occurrence of elevation in the serum levels of liver enzymes AST and ALT as well as urea and creatinine levels in the group received TTCE. This was associated with a significant drop in zinc level. The liver showed marked dilatation of central vein and blood sinusoids, some liver cells revealed deeply acidophilic homogenous cytoplasm with pyknotic nuclei while other cells showed vacuolated cytoplasm. The lung showed histological changes in both conducting and respiratory protions. There was also a significant increase of the DNA content of the hepatocytes and pneumocytes in this group. Administration of zinc combined with TTCE showed a statistically significant limitation in the degree of toxicity of TTCE. This protective effect was found to be significantly less obvious for silibinin. Zinc plays its protective role via its antioxidant effect that antagonizes the oxidative stress induced by TTCE. The study recommends the use of extra doses of zinc especially in those who are exposed to TTCE in industrial fields