Sex differences in choline-deficient diet-induced steatohepatitis in mice

Alcoholic steatohepatitis (ASH) and nonalcoholic steatohepatitis (NASH) are common liver diseases in the United States. ASH and NASH occur more frequently in women than in men, and liver injury is also more severe in women. The role of estrogens in ASH has been well established, but their role in NASH has received relatively little study. The purpose of this study was to evaluate the effect of estrogens in methionine-choline deficient diet (MCDD)-induced steatohepatitis in mice. The degree of steatohepatitis was evaluated in males and in intact and ovariectomized females that were fed MCDD for 4 weeks, and in females that were fed MCDD containing tamoxifen. Hematoxylin and eosin-stained sections of livers showed marked steatohepatitis in all experimental groups. Compared to the control group, markers of hepatocyte injury such as aspartate transaminase (AST), alanine transaminase (ALT), and liver triglyceride levels increased significantly in males and in intact and ovariectomized female mice that were fed MCDD. Also, it was interesting that levels of AST and ALT increased much more in the MCDD + tamoxifen group than in the MCDD group. In female mice fed MCDD, hepatocyte proliferative and apoptotic indices increased slightly compared to mice that were fed a normal diet. Based on these results, it can be concluded that MCDD-induced steatohepatitis is comparable in male and female mice, and that ovariectomy or antiestrogen treatment had no protective effect in MCDD-induced steatohepatitis.