Atherosclerosis Susceptibility in LDLr-Deficient Mice

Male apolipoprotein B100-only, low density lipoprotein receptor (LDLr) deficient (LDLr^-/-Apob^100/100) mice were used in this study. These mice were chosen based on previous reports documenting their “human-like” lipoprotein profile,20 (link) atherosclerosis susceptibility,20 (link) and responsiveness to dietary fatty acids.21 (link) All mice were on a mixed background (∼75% C57BL/6 and ∼25% 129Sv/Jae). At 6 weeks of age, the mice were switched from a diet of rodent chow to one of two synthetic diets containing 12% of energy as saturated fatty acid (SFA)-enriched fat (palm oil) or monounsaturated fatty acid (MUFA)-enriched fat (oleinate-enriched safflower oil) with 0.1% (w/w) cholesterol added. Please refer to Supplemental Table 1 (online) for complete analysis of dietary fatty acid composition. In conjunction with diet, mice were injected biweekly with either saline, 25 mg/kg of a non-targeting ASO (control ASO; 5 ′- TCCCATTTCAGGAGACCTGG -3′), or 25 mg/kg of an ASO targeting the knockdown of SCD1 (SCD1 ASO; 5′-GCTCTAATCACCTCAGAACT -3′). These phosphorothioate modified ASO compounds were generously provided by ISIS Pharmaceuticals, Inc. (Carlsbad, CA). Body weight was measured weekly, and food intake was measured at four weeks and eight weeks of diet/ASO treatment. All experimental animals were sacrificed after 20 weeks of parallel dietary and ASO treatment. All mice were maintained in a pathogen-free animal facility, and experimental protocols were approved by the institutional animal care and use committee at the Wake Forest University School of Medicine.