DPA n-3, DPA n-6 and DHA improve lipoprotein profiles and aortic function in hamsters fed a high cholesterol diet

The present study examined the cholesterol-lowering activity of omega-3 docosapentaenoic acid (DPA n-3), omega-6 docosapentaenoic acid (DPA n-6) and docosahexaenoic acid (DHA), and their interaction with gene expression of transporters, receptors and enzymes involved in cholesterol absorption and metabolism as well as their effect on aortic function. Forty hamsters were fed either the control diet containing 0.4% stearic acid or one of the three experimental diets containing 0.4% DPA n-3, 0.4% DPA n-6 and 0.4% DHA. Results showed that supplementation of these three fatty acids reduced plasma total cholesterol (TC) and non high-density-lipoprotein cholesterol (non-HDL-C) by 29-33% and 29-50%, respectively, compared with the control. The reduction in TC and non-HDL-C was accompanied by down-regulation of hepatic SREBP-2 and HMG-CoA reductase. Aorta from DPA n-3 and DHA groups was found to have significantly lesser tension and relax better than that from the control and DPA n-6 hamsters, largely mediated by their inhibition on the gene expression of cycloxygense-2 (COX-2). It was concluded that all three fatty acids were beneficial in improving lipoprotein profile with DPA n-3 and DHA having better effect on aortic function.