Co-administration of metformin and N-acetylcysteine with dietary control improves the biochemical and histological manifestations in rats with non-alcoholic fatty liver

Non-alcoholic fatty liver disease (NAFLD) is a burgeoning health problem that affects 1/3 of the adult population and an increasing number of children in developed countries. Oxidative stress and insulin resistance are the mechanisms that seem to be mostly involved in its pathogenesis. This study was conceived in a NAFLD rat model to evaluate the efficacy of both metformin (MTF) and N-acetylcysteine (NAC) with dietary control on biochemical and histologic liver manifestations. Rats were classified into nine groups; normal (I), NAFLD-induced by feeding high-fat diet (HFD; II) for 12 weeks, NAFLD switched to regular diet (RD; III), NAFLD-HFD or -RD treated with MTF in a dose of 150 mg/kg (IV, V), NAC in a dose of 500 mg/kg (VI, VII) or MTF+NAC (VIII, IX) respectively for 8 weeks. After 20 weeks, the rats in group II showed notable steatosis, lobular inflammation, fibrosis accompanied with elevated (P < 0.05) serum alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma glutamyl transferase (gamma-GT), cholesterol, triglycerides, LDL, VLDL, leptin, tumor necrosis factor (TNF-alpha), transforming growth factor (TGF-beta 1) and hepatic malondialdehyde (MDA) compared with group I. Meanwhile, hepatic superoxide dismutase (SOD), glutathione GSH with serum HDL, adiponectin were significantly decreased (P < 0.05). These changes were to a less extent in group III. MTF or NAC individually resulted in improvement of most of these biochemical and histological parameters. These improvements were more pronounced in the combined groups VIII and IX versus each drug alone. NAC supplementation concomitant with MTF could be beneficial for the treatment of NAFLD and prevention of nonalcoholic steatohepatitis (NASH).