Contrasting effect of fish oil supplementation on the development of atherosclerosis in murine models

Objective: Increased fish oil intake is associated with protection against coronary heart disease and sudden death, while effects on atherosclerosis are controversial. We explored the effects of supplementing fish oil (rich in n-3 polyunsaturated fatty acids, PUFA) or corn oil (rich in n-6 PUFA) in two different models of atherosclerosis. Methods and Results: Sixty-three low density lipoprotein receptor-deficient (LDLR-/-) mice and sixty-nine apolipoprotein E-deficient (apoE(-/-)) mice were fed diets without supplementations or supplemented with either 1% fish oil or 1% corn oil. In apoE(-/-) mice, neither fish oil nor corn oil had any major impact on plasma lipids or atherosclerosis. In LDLR-/- mice, conversely, the fish oil and the corn oil group had lower levels of LDL-cholesterol and triglycerides and had lesser atherosclerosis in the aortic root and in the entire aorta (P <0.01 versus unsupplemented group). Atherosclerosis was significantly less in the fish oil group compared with the corn oil group when evaluated en face in the aortic arch (area positive to lipid staining: 32% with fish oil versus 38% with corn oil; 48% with unsupplemented diet). Conclusions: n-3 and n-6 PUFA supplementation retarded the development of atherosclerosis in LDLR-/- mice, with a stronger effect seen with n-3 PUFA. There was an important strain-dependence of the effect, with no protection against atherosclerosis in apoE(-/-) mice. (c) 2005 Elsevier Ireland Ltd. All rights reserved.