Inhibitory effects of silymarin on hepatic fibrosis induced by dimethylnitrosamine: experiment with rats

Abstract

To investigate the antifibrotic effects of silymarin on hepatic fibrosis. Sixty-one male Wistar rats were randomly divided into three groups: control group (15 rats); DMN model group (23 rats), injected intraperitoneally with dimethylnitrosamine (DMN) 10 mg/kg twice per week for 8 weeks to induce hepatic fibrosis; and silymarin group (23 rats), injected intraperitoneally with DMN and given silymarin 50 mg/kg by gastric gavage daily for 8 weeks. Eight weeks late all rats were sacrificed. Blood samples were collected to measure the alanine transaminase (ALT), aspirate aminotransferase (AST), albumin, and total bilirubin (TBIL). The hydroxyproline (Hyp) content in the liver tissue was measured. The histopathological changes as well as the fibrosis stages and score were examined by microscopy. The levels of ALT, AST, and TBIL of the silymarin groups were 59 U/L +/- 19 U/L, 159 U/L +/- 39 U/L, and mean rank 24 respectively, all significantly lower than those of the DMN model group (128 U/L +/- 25 U/L, 246 U/L +/- 61 U/L, and mean rank 37 respectively, P < 0.01, P = 0.001, and P = 0.003). Compared with DMN rats, the level of Hyp of the silymarin was lower by 42.6%, the hepatic score of the silymarin was 6.2 +/- 2.4, significantly than that of the DMN model group (12.8 +/- 4.4, P = 0.001), and more cases in the silymarin group were at the lower stages. Silymarin markedly inhibits and reverse the progression of hepatic fibrosis induced by dimethylnitrosamine.