Monounsaturated fat decreases hepatic lipid content in non-alcoholic fatty liver disease in rats

Abstract

To evaluate the effects of different types of dietary fats on the hepatic lipid content and oxidative stress parameters in rat liver with experimental non-alcoholic fatty liver disease (NAFLD). A total of 32 Sprague-Dawley rats were randomly divided into five groups. The rats in the control group (n = 8) were on chow diet (Group 1), rats (n = 6) on methionine choline-deficient diet (MCDD) (Group 2), rats (n = 6) on MCDD enriched with olive oil (Group 3), rats (n = 6) on MCDD with fish oil (Group 4) and rats (n = 6) on MCDD with butter fat (Group 5). After 2 mo, blood and liver sections were examined for lipids composition and oxidative stress parameters. The liver weight/rat weight ratio increased in all treatment groups as compared with the control group. Severe fatty liver was seen in MCDD + fish oil and in MCDD + butter fat groups, but not in MCDD and MCDD + olive oil groups. The increase in hepatic triglycerides (TG) levels was blunted by 30% in MCDD + olive oil group (0.59 +/- 0.09) compared with MCDD group (0.85 +/- 0.04, P < 0.004), by 37% compared with MCDD + fish oil group (0.95 +/- 0.07, P < 0.001), and by 33% compared with MCDD + butter group (0.09 +/- 0.1, P < 0.01). The increase in serum TG was lowered by 10% in MCDD + olive oil group (0.9 +/- 0.07) compared with MCDD group (1.05 +/- 0.06). Hepatic cholesterol increased by 15-fold in MCDD group [(0.08 +/- 0.02, this increment was blunted by 21% in MCDD + fish oil group (0.09 +/- 0.02)]. In comparison with the control group, ratio of long-chain polyunsaturated fatty acids omega-6/omega-3 increased in MCDD + olive oil, MCDD + fish oil and MCDD + butter fat groups by 345-, 30- and 397-fold, respectively. In comparison to MCDD group (1.58 +/- 0.08), hepatic MDA contents in MCDD + olive oil (3.3 +/- 0.6), MCDD + fish oil (3.0 +/- 0.4), and MCDD + butter group (2.9 +/- 0.36) were increased by 108%, 91% and 87%, respectively (P < 0.004). Hepatic paraoxonase activity decreased significantly in all treatment groups, mostly with MCDD + olive oil group (-68%). Olive oil decreases the accumulation of triglyceride in the liver of rats with NAFLD, but does not provide the greatest antioxidant activity.