Regulation of adipokines by polyunsaturated fatty acids in a rat model of non-alcoholic steatohepatitis.

Abstract

Recent evidence has indicated that polyunsaturated fatty acids (PUFA), such as omega-3 PUFA, have protective effects on a range of chronic inflammatory conditions, including obesity, and may play a role in the reversal of steatohepatitis. However, the effects of omega-3 PUFA on adipokine expression and hepatic lipid metabolism have not been well evaluated. Thus, the aim of our study was to investigate the effects of PUFAs on adipokines, as well as lipid and glycometabolism, in a rat model of non-alcoholic steatohepatitis (NASH). Male Sprague-Dawley rats were divided into control, model and therapy groups. The control group received a normal diet, while the model and therapy groups received a high-fat diet. On the eighth week of high-fat diet, the therapy group was treated with omega-3 PUFA (1.0 g/d) daily. At the end of 20 weeks, serum biochemistry indices were measured and adipokine levels in serum and liver samples were detected with ELISA, Western blotting and real time fluorescence quantitative PCR (qRT-PCR). The weight, biochemical parameters and adipokine levels in serum of the model group were elevated compared to the control group (P < 0.05). In addition, the protein and mRNA expression levels of adipokines in the liver were significantly altered compared to the control group (P < 0.01). The therapy group was characterized by decreased weight and biochemical indices (P < 0.05) compared with the model group. Supplementing high-fat diet with omega-3 PUFA decreased serum levels of leptin and resistin, while adiponectin levels were slightly elevated. In liver tissue samples, the protein and mRNA expression levels of adipokines were significantly improved (P < 0.01) in the therapy group compared to the model group. Omega-3 PUFA improved lipid and glycometabolism in NASH rats and regulated adipokine expression, indicating that omega-3 PUFA may have a therapeutic benefit for patients with NASH.