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

Aim: 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).
Methods: 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.
Results: 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%).
Conclusion: Olive oil decreases the accumulation of triglyceride in the liver of rats with NAFLD, but does not provide the greatest antioxidant activity.