New therapeutic aspect for carvedilol: antifibrotic effects of carvedilol in chronic carbon tetrachloride-induced liver damage.

Portal hypertension is a common complication of chronic liver diseases associated with liver fibrosis and cirrhosis. At present, beta-blockers such as carvedilol remain the medical treatment of choice for protection against variceal bleeding and other complications. Since carvedilol has powerful antioxidant properties we assessed the potential antifibrotic effects of carvedilol and the underlying mechanisms that may add further benefits for its clinical usefulness using a chronic model of carbon tetrachloride (CCl4)-induced hepatotoxicity. Two weeks after CCl4 induction of chronic hepatotoxicity, rats were co-treated with carvedilol (10mg/kg, orally) daily for 6weeks. It was found that treatment of animals with carvedilol significantly counteracted the changes in liver function and histopathological lesions induced by CCl4. Also, carvedilol significantly counteracted lipid peroxidation, GSH depletion, and reduction in antioxidant enzyme activities; glutathione-S-transferase and catalase that was induced by CCl4. In addition, carvedilol ameliorated the inflammation induced by CCl4 as indicated by reducing the serum level of acute phase protein marker; alpha-2-macroglobulin and the liver expression of nuclear factor-kappa B (NF-κB). Finally, carvedilol significantly reduced liver fibrosis markers including hydroxyproline, collagen accumulation, and the expression of the hepatic stellate cell (HSC) activation marker; alpha smooth muscle actin. In conclusion, the present study provides evidences for the promising antifibrotic effects of carvedilol that can be explained by amelioration of oxidative stress through mainly, replenishment of GSH, restoration of antioxidant enzyme activities and reduction of lipid peroxides as well as amelioration of inflammation and fibrosis by decreasing collagen accumulation, acute phase protein level, NF-κB expression and finally HSC activation.