Induction of non-alcoholic fatty liver disease and insulin resistance by feeding a high-fat diet in rats: does coenzyme Q monomethyl ether have a modulatory effect?

Abstract

Objective The aim of this study was to investigate the development of non-alcoholic fatty liver disease (NAFLD) in response to a high-fat diet in rats and to test the hypothesis that dietary coenzyme Q monomethyl ether (CoQme) has antisteatogenic effects. Methods Rats were fed a standard low-fat diet (control) for 18 wk or a diet containing 35% fat (57% metabolizable energy) for 10 wk, then divided into three groups for the following 8 wk. One group was given CoQ9me (30 mg/kg body weight per day in 0.3 mL olive oil: high fat + CoQ9me), the second olive oil (0.3 mL/d) only (high fat + olive oil), and the third group received no supplements (high fat). Results Insulin levels and the activity of alanine aminotransferase in the plasma were significantly increased in all high-fat diet groups, and the homeostasis model assessment of insulin resistance indicated insulin resistance. Triacylglycerol concentrations in whole plasma and in very low-density lipoprotein and low-density lipoprotein fractions were also raised. Liver histology showed lipid accumulation in animals fed the high-fat diets, and liver triacylglycerol levels were increased (2.5- to 3-fold) in all high-fat diet groups. These effects were not changed by the administration of CoQ9me. Conclusions Rats fed a diet with 57% energy from fat showed insulin resistance, hypertriglyceridemia, increased very low-density lipoprotein production, hepatic steatosis, and liver damage, and thus provide a good model for the early stages of NAFLD. Dietary CoQ9me, however, did not ameliorate the damaging effects of the high-fat diet.