C3H apoE(-/-) mice have less atherosclerosis than C57BL apoE(-/-) mice despite having a more atherogenic serum lipid profile

Wild-type C57BL mice are known to be susceptible to diet-induced atheroscle rosis, whilst C3H mice are resistant. We investigated the effect of these b ackground strains on the hyperlipidaemia and atherosclerosis that develops in mice deficient in apolipoprotein E (apoE(-/-)). Male and female apoE(-/- ) mice on C3H/HeNHsd (C3H) and C57BL/6J (C57) backgrounds were fed atheroge nic Western diet for 12 weeks. Serum cholesterol and triglyceride concentra tions were measured and atherosclerosis quantified in the aortic sinus. C3H apoE(-/-) mice fed normal diet had 1.5-2 fold higher serum cholesterol lev els than C57 apoE(-/-) mice and 4-5 fold higher serum triglyceride concentr ations. Feeding Western diet caused a 4-5 fold increase in serum cholestero l in all mice, but levels of triglyceride were either attenuated or were un affected in C3H apoE(-/-) and C57 apoE(-/-) mice, respectively. C3H apoE(-/ -) mice had approximately 2 fold higher serum cholesterol and 4 fold higher triglyceride concentrations than the C57 apoE(-/-) mice throughout the stu dy. Serum triglyceride concentrations were 35-108% higher in male C3H apoE( -/-) than female C3H apoE(-/-) mice. Most of the lipids were present in the very low density lipoprotein (VLDL)/chylomicron fraction in both strains o f mice whether they were fed normal or Western diet. Notwithstanding the lo wer plasma lipid concentrations, atherosclerotic lesion areas were more tha n 2-fold larger in C57 apoE(-/-) than in C3H apoE(-/-) mice (males 68 +/- 1 1 x 10(3) vs 30 +/- 6 x 10(3), females 102 +/- 12 x 10(3) vs 41 +/- 8 x 10( 3) mu m(2), mean +/- SEM). (C) 2000 Elsevier Science Ireland Ltd. All right s reserved.