The effect of thistle (Silybum marianum L.) on the caspase-3, caspase-9, bax, -2 protein expression and DNA damage in rats with carbon tetrachloride (CCl4)-induced liver damage

Thistle is a strong antioxidant plant having protecting effect particularly on the liver. 28 male Wistar albino rats were used in this thesis study that we investigated the effects of milk thistle taken via drink water on rats modified with liver damage by carbon tetrachloride (CCl4). Groups were divided into four, and 7 rats involved in each group. CCl4 (2 ml/kg body weight) has been injected to the rats in groups of CCl4 and CCl4+T, intraperitoneally twice weekly for four weeks. All rats were fed a standard diet. Drinking water were given to NC and CCl4 groups; and boiled 10 % thistle extract added drinking water were given to PC and CCl4+T groups. After 4 weeks, the rats were decapitated and the liver tissues were examined. Hepatic tissue bax, bcl-2, caspase-3, caspase-9 protein expression levels were determined by Western blotting techniques. DNA damage in the liver was determined by DNA agarose gel electrophoresis. Lipid peroxidation occurring in liver tissue were determined by MDA analysis. Thistle application, in CCl4+T group, compared to CCl4 group, bax, bcl-2, caspase-3, caspase-9 protein expression creates a significant difference (p<0.05). Caspase-3 and caspase-9 protein expression levels increased, but bax and bcl-2 protein expression levels were decreased through the application of thistles. The rate of apoptotic index was observed higher in CCl4+T group than CCl4 group at Tunel assay examinations. Thistle application, showed a decrease at CCl4+T group compared to CCl4 group in terms of the level of DNA damage. These results shows that thistle reduce the rate of liver damage at Wistar albino rats and these findings will be guiding in research of inhibitory effect of liver damage of humans like rats.