Protective role of silymarin and D-penicillamine against lead-induced liver toxicity and oxidative stress

This study was performed to assess hepatotoxicity and alterations in liver antioxidant defence in acute lead (Pb) exposure and the protective effects of silymarin in comparison to D-penicillamine in rats. Forty eight Albino rats were divided in eight groups and received the following treatments in a 10-day experiment - group 1: normal saline as control; group 2: 25-mg/kg Pb acetate, intraperitoneally (IP) for the last 5 days; group 3: 100-mg/kg D-penicillamine, IP for the last 5 days; group 4: 200-mg/kg silymarin, orally for 10 days; and groups 5, 6, 7 and 8: in addition to Pb, they received D-penicillamine, for the last 5 days, silymarin for 10 days, a combination of silymarin for 10 days and D-penicillamine for the last 5 days and silymarin for the last 5 days, respectively. Pb acetate exposure induced significant elevation in serum alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) enzyme activities in group 2 compared to control group. Significant reductions in serum total protein and albumin in all Pb-exposed groups and in serum glucose in groups 2, 6 and 8 were also observed. Liver tissue superoxide dismutase and glutathione peroxidase were significantly lower in groups 2 and 8 compared to control group. Silymarin pretreatment and D-penicillamine administration in groups 5, 7 and 8 could significantly lower ALP, ALT and AST and improve liver antioxidant enzymes. Thus, acute Pb exposure induced hepatotoxicity with suppression of liver antioxidant defence system and silymarin, as an antioxidant could alleviate this effect.