effects of silymarin on cadmium-induced toxicity in rats

background: cadmium has toxicological significance and there is no effective therapy for its poisoning. objective: the effects of silymarin on the parameters indicative of cadmium-induced toxicity were studied in rats. methods: 130 adult male wistar rats were divided into 13 groups each comprising 10 rats. 1 group as control group was not administered neither cadmium nor silymarin. cadmium chloride (3mg/kg/week) was administered intraperitoneally to 12 groups for 6 weeks. the 12 groups were divided into two sets of 6 groups. in the first set, one group was kept as control and silymarin in the doses of 15, 30, 60, 120 and 240 mg/kg/week was administered orally to each group for 6 weeks. in the second set, one group was kept as control and the aforementioned doses of silymarin were administered orally to each group for 6 weeks after 6 weeks of cadmium administration.  blood samples were taken after 6 weeks from the first set and after 12 weeks from the second set to determine ast (aspartate aminotransferase), alt (alanine aminotransferase) and alp (alkaline phosphatase) levels and catalase activity. results: in the first set in all silymarin treated groups, alp level significantly decreased compared with control and in the second set, ast level decreased significantly compared with control only in groups treated with high doses of silymarin. different doses of silymarin except the dose of 15 mg/kg significantly increased serum catalase activity compared with control in both sets.  conclusion: silymarin prevents and reverses cadmium-induced toxicity possibly through its anti-oxidative property in rats.