Atherosclerosis in low density lipoprotein receptor knockout mice fed cholesterol and soybean oil

In order to study aortic atherosclerosis and atherosclerotic response to dietary cholesterol and soybean oil in homozygous LDLR-/- mice, the 16 weeks old animals were randomized in 4 groups either fed standard diet (no cholesterol added, group I, 12 male and 12 female), standard diet added 0.5% cholesterol (group II, 12 male and 12 female), standard diet added 10% soybean oil (group Iii, 7 male) or standard diet added 0.5% cholesterol and 10% soybean oil (group IV, 7 male) for 14 weeks. At termination, the plasma cholesterol of males was: 9.4 mmol/I +/- 0.3 (SD) (group I), 34.4 +/- 6.2 (group II), 9.9 +/- 0.07 (group III), 32.6 +/-0.1 (group IV), and of females 6.9 +/- 2.7 (group I) and 31.7 +/- 4.4 (group II). No apparent difference in plasma triglyceride levels was observed between the groups of either sexes. Aortic atherosclerosis (ratio intima/media) in males was 0.17 +/- 0.09 (SD) (group I), 0.96 +/- 0.32 (group II, p<0.05 compared to other male groups), 0.21 +/- 0.09 (group III), and 0.59 +/- 0.34 (group IV, p<0.05 compared to other male groups), and in females 0.12 +/- 0.08 (group I) and 0.83 +/- 0.30 (group II, p<0.05 compared to female group I). No sex difference in the ratio intima/media was recorded for LDLR-/- mice on standard or cholesterol diet. It was concluded that spontaneous hypercholesterolemia and aortic atherosclerosis in LDLR-/- mice were significantly increased by 0.5% cholesterol addition to the standard diet but were not affected by 10% soybean oil addition to the standard diet, and that 10% soybean oil addition to the 0.5% cholesterol diet did not affect cholesterol induced hypercholesterolemia but significantly decreased cholesterol induced aortic atherosclerosis. (C) 1999 Elsevier Science Inc.