Proteomics Analysis to Identify and Characterize the Molecular Signatures of Hepatic Steatosis in Ovariectomized Rats as a Model of Postmenopausal Status

Postmenopausal women are particularly at increased risk of developing non-alcoholic fatty liver disease (NAFLD). Here we aimed to determine the impact of postmenopausal-induced NAFLD (PM-NAFLD) in an ovariectomized rat model. Sixteen six-week-old Sprague-Dawley female rats were randomly divided into two groups (eight per group), for sham-operation (Sham) or bilateral ovariectomy (Ovx). Four months after surgery, indices of liver damage and liver histomorphometry were measured. Both serum aspartate aminotransferase (AST) and alanine aminotranferease (ALT) levels were significantly higher in the Ovx than Sham group. We performed quantitative LC-MS/MS-based proteomic profiling of livers from rats with PM-NAFLD to provide baseline knowledge of the PM-NAFLD proteome and to investigate proteins involved in PM-NAFLD by ingenuity pathways analysis (IPA) to provide corroborative evidence for differential regulation of molecular and cellular functions affecting metabolic processes. Of the 586 identified proteins, the levels of 59 (10.0%) and 48 (8.2%) were significantly higher and lower, respectively, in the Ovx group compared to the Sham group. In conclusion, the changes in regulation of proteins implicated in PM-NAFLD may affect other vital biological processes in the body apart from causing postmenopause-mediated liver dysfunction. Our quantitative proteomics analysis may also suggest potential biomarkers and further clinical applications for PM-NAFLD.