ABSTRACT
Chronic liver diseases, such as fibrosis or cirrhosis, are more common in men than in women. This gender difference may be related to the effects of sex hormones on the liver. The aim of the present work was to investigate the effects of estrogen on CCL 4 induced fibrosis of the liver rats. Liver fibrosis was induced in male and female rats by CCL 4 administration in a dose of 2mg/kg/SC/twice weekly. Along with CCL 4 treatment a subgroup of the male rats received estradiol [1mg/kg] twice weekly, while tamoxifen [6mg/kg/day/orally] was given to a female subgroup. At the end of 8 weeks, all the rats were sacrified to study the serum indicators and the livers. The fibrotic response of the female liver to CCL 4 treatment was significantly weaker than that of male liver. In addition, estradiol treatment reduced aspartate aminotransferase [AST] and alanine aminotransferase [ALT] in sera, suppressed hepatic collagen content and malondialdehyde [MDA], decreased the areas of hepatic cirrhosis significantly in male fibrotic rats induced by CCL 4 administration. Whereas, tamoxifen had the opposite effect in female fibrotic rats. We concluded that estradiol reduces CCL 4 induced hepatic fibrosis in rats. The antifibrogenic role of estrogen in the liver may be one reason for the sex associated differences in the progression from hepatic fibrosis to cirrhosis