Improved antifibrotic effect of a combination of verapamil and silymarin in rat-induced liver fibrosis

ABSTRACT

Liver fibrosis progresses to cirrhosis in several settings, for example, severe acute alcoholic hepatitis, and hepatitis C virus [HCV] reinfection after liver transplantation. Cirrhosis produces hepatocellular dysfunction, which is also a risk factor for hepatocellular carcinoma. We studied verapamil as a prophylactic, therapeutic antifibrotic drug alone and in combination with silymarin in experimental rat's liver-induced fibrosis. Liver fibrosis was induced by intra-peritoneal injection of rats with pig serum 0.5 ml twice weekly for 6 weeks, which resulted in score three fibrosis. Prophylactic verapamil alone and silymarin alone and a combination of both were administered at the same time of induction of liver fibrosis and continued for the duration of induction. Therapeutic verapamil was started on the last day of fibrosis induction and continued for 4 weeks. The extent of liver fibrosis was evaluated using Ishak's fibrosis score. Serum alanine aminotransferase [ALT] was measured for follow-up. Compared to fibrotic model rats, prophylactic verapamil, silymarin and combined verapamil plus silymarin significantly resulted in lower serum ALT levels. Prophylactic use of verapamil and silymarin each alone revealed score 2 fibrosis with positive alpha-SMA immunostaining; while prophylactic treatment with combined verapamil plus silymarin revealed no fibrosis supported by negative alpha-SMA immunostaining. Verapamil treated fibrotic rat's liver revealed significant regression in liver fibrosis scores with positive alpha-SMA immunostaining. Verapamil alone has a more significant prophylactic than therapeutic antifibrotic effect against induced liver fibrosis; it was more significant than silymarin. The combination of verapamil and silymarin, showed the best protection through their synergistic antifibrotic effect