Prophylactic and therapeutic effects of silymarin on acute hepatotoxicity due to administration of mebendazole in dogs

In the present study, effect of silymarin was evaluated as a protective drug of liver against acute hepatotoxicity due to administration of mebendazole in German shepherd dogs (mixed breeds). Twenty five healthy dogs were randomly allotted to five equal groups. Dogs in group A were given mebendazole with single dose 150 mg⁄kg, p.o.; group B consisted of dogs that received silymarin with single dose 30 mg⁄kg, p.o. concurrent with mebendazole administration; groups C, D and E were treated like group B, but silymarin was administered 2, 12 and 24 h after administration of mebendazole respectively. The serum concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and total and direct bilirubin were measured before administration of mebendazole and 2, 12, 24 and 72 h later as indices of liver injury. A single oral administration of mebendazole significantly elevated serum concentrations of ALT, AST, ALP, LDH in all cases of group A (P<0.05), after 24 h. In both groups of B and C, levels of serumenzyme activities remained within the normal values. The difference was significant between groups B and C with group A (P<0.05). Levels of serumenzyme activities were higher than normal values in three cases of the group D and in all dogs of the group E. This study showed that silymarin could protect liver tissue against oxidative stress in dogs with mebendazole intoxication particularly in the first 2 hours after exposure.