Abstract
Dietary intake of long-chain n-3 polyunsaturated fatty acids (PUFA) reduces the risk for atherosclerosis. Here we examine the effect of a fish oil (FO)-rich diet on the development of atherosclerotic lesions in apolipoprotein E-deficient (apoE(-/-)) mice, which are vulnerable because of their high plasma cholesterol and triacylglycerol levels, focusing on the expression of endothelial adhesion molecules. Mice were fed semi-purified diets containing 5% corn oil (CO), rich in n-6 PUFA or menhaden oil as FO, rich in long-chain n-3 PUFA and 0.15% cholesterol after reaching 4 weeks of age, and they were killed when they were 4 weeks, 12 weeks, 18 weeks or 24 weeks old. Oxidative stress in plasma and aortic tissue was not increased in mice fed the FO-rich diet, despite its high peroxidizability index. A reduction of stenosis and intrusion at the aortic root, a decrease in the surface area of atherosclerotic lesions at the aorta and a decrease in P-selectin, vascular cellular adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) expression were observed in FO-fed mice compared to CO-fed mice. It seems likely that the reduced expression of VCAM-1 and ICAM-1 could be transcriptionally regulated by nuclear factor-kappaB in the aortic root. The protective effect of FO against atherosclerosis was more evident at early ages. In conclusion, FO reduces adhesion molecule expression in lesions in apoE(-/-) mice. Because these molecules are involved in lesion progression the effect of FO may explain the observed decrease in atherogenesis.