Effects of estrogen and androgen deprivation on the progression of non-alcoholic steatohepatitis (NASH) in male Sprague - Dawley rats

Abstract

Aim: We studied the mechanisms of estrogen/androgen involvement in the induction of NASH by treating Sprague-Dawley (SD) rats fed with a normal or high fat (HF) diet by depriving them of endogenous estrogens/ androgens. Methods: Male adult SD rats (n = 10/group) on normal or HF diets were treated for 75days either with tamoxifen (Tam) or flutamide (Flu) or Tam+Flu in order to induce NASH. We analyzed histopathologically the liver samples from the treated groups for NASH, checked the serum biochemical and lipid profile markers and finally analyzed the signal pathways underlying the molecular mechanisms for the induction process of NASH. Results: Deprivation of endogenous estrogens and/or androgens (Tam or Flu or Tam+Flu) without the HF diet did not induce NASH. Tam or Tam+Flu induced NASH, compared to milder lesions without fibrosis in HF diet and Flu-treated liver. Serum alanine aminotransferase or lipid profile markers further proved the Tam, Flu or Tam+Flu effects on the induction of NASH in conjunction with a HF diet. Tam treatment predominantly downregulated the ERα and FAS and upregulated UCP2 and TNF-α. Conclusions: Deprivation of endogenous estrogen/androgens in conjunction with a HF diet may induce NASH where the downregulated ERα and FAS, and upregulated UCP2 and TNF-αcould be involved in their molecular pathomechanism pathways. These results could suggest the potential negative roles of estrogenic/androgenic depriving compounds in the induction of NASH, along with obesity. © 2009 The Japan Society of Hepatology.