Eicosapentaenoic acid modulates fatty acid metabolism and inflammation in Psammomys obesus

• Eicosapentaenoic acid supplemented diet (EPAD) decreased liver mass in Psammomys obesus.
• EPAD normalizes high calorie diet-induced metabolic alterations.
• EPAD decreased liver n-6/n-3 PUFA ratio and stearoyl-CoA desaturase 1 index.
• EPAD downregulated liver lipogenesis and upregulated fatty acid oxidation.
• EPAD decreased expression of mRNA of pro-inflammatory genes in liver and adipose tissue.

The desert gerbil, Psammomys obesus, is a unique polygenic animal model of metabolic syndrome (insulin resistance, obesity and type 2 diabetes), and these pathological conditions resemble to those in human beings. In this study, the animals were fed ad libitum either a natural diet (ND) which contained desertic halophile plants or a standard laboratory diet (STD) or a diet which contained eicosapentaenoic acid (EPA), hence, termed as EPA diet (EPAD). In EPAD, 50% of total lipid content was replaced by EPA oil. By employing real-time PCR, we assessed liver expression of key genes involved in fatty acid metabolism such as PPAR-α, SREBP-1c, LXR-α and CHREBP. We also studied the expression of two inflammatory genes, i.e., TNF-α and IL-1β, in liver and adipose tissue of these animals. The STD, considered to be a high caloric diet for this animal, triggered insulin resistance and high lipid levels, along with high hepatic SREBP-1c, LXR-α and CHREBP mRNA expression. TNF-α and IL-1β mRNA were also high in liver of STD fed animals. Feeding EPAD improved plasma glucose, insulin and triacylglycerol levels along with hepatic lipid composition. These observations suggest that EPA exerts beneficial effects in P. obesus.