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Updated: Oct 2, 2026
Cholesterol Efflux Assay
Published on: March 6, 2012
Macrophage cholesterol efflux to free apoprotein A-I in C3H and C57BL/6 mice
Olga Stein1, Mazal Ben-Naim, Yedida Dabach
1Department of Experimental Medicine and Cancer Research, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Abstract:
Cholesterol efflux from peritoneal macrophages of mice C57BL/6 susceptible and C3H resistant to atherosclerosis was compared, using apoprotein A-I as acceptor. The elicited macrophages were labeled with 3H-cholesterol and cholesterol enriched by incubation for 24 h with acetylated LDL. After incubation for 6 or 24 h, 3H-cholesterol efflux to free apoA-I (10 microg/ml) was significantly higher with macrophages derived from C3H mice compared to C57BL/6 mice. The cells were also pretreated with 0.3-0.45 mM cyclic AMP, 10 microM 9-cis-retinoic acid or 10 microM 22(R)-hydroxycholesterol, RXR and LXR ligands. Treatment with cyclic AMP, RXR, or LXR ligands, resulted in enhancement of 3H-cholesterol efflux in both strains. Under all conditions, 3H-cholesterol efflux was significantly higher in C3H compared to C57BL/6 macrophages. In conclusion, the higher cholesterol efflux from C3H macrophages could contribute toward the resistance of this strain to diet-induced atherosclerosis despite hypercholesterolemia.
Insights
Cholesterol efflux is higher in C3H mice macrophages compared to C57BL/6 mice, contributing to atherosclerosis resistance. This enhanced efflux was observed even after treatment with cyclic AMP, RXR, and LXR ligands.
Area of Science:
- Immunology
- Cardiovascular Biology
- Metabolic Diseases
Background:
- Atherosclerosis susceptibility varies among mouse strains, with C57BL/6 being susceptible and C3H resistant.
- Cholesterol efflux from macrophages is a critical process in preventing atherosclerosis.
- Understanding strain-specific differences in cholesterol metabolism is key to developing targeted therapies.
Purpose of the Study:
- To compare cholesterol efflux capacity between peritoneal macrophages of atherosclerosis-susceptible (C57BL/6) and resistant (C3H) mice.
- To investigate the effect of cyclic AMP, RXR, and LXR ligands on cholesterol efflux in these macrophage populations.
- To determine if enhanced cholesterol efflux contributes to the observed resistance to atherosclerosis in C3H mice.
Main Methods:
- Peritoneal macrophages from C57BL/6 and C3H mice were isolated and labeled with 3H-cholesterol.
- Macrophages were enriched with cholesterol using acetylated LDL.
- Cholesterol efflux to apoprotein A-I (apoA-I) was measured after incubation with or without cyclic AMP, RXR, or LXR ligands.
Main Results:
- 3H-cholesterol efflux was significantly higher in C3H macrophages compared to C57BL/6 macrophages under basal conditions.
- Pretreatment with cyclic AMP, RXR ligands, or LXR ligands enhanced cholesterol efflux in both mouse strains.
- Despite enhancements, C3H macrophages consistently demonstrated significantly higher cholesterol efflux than C57BL/6 macrophages.
Conclusions:
- C3H mice exhibit a higher intrinsic capacity for cholesterol efflux from peritoneal macrophages compared to C57BL/6 mice.
- This enhanced cholesterol efflux in C3H macrophages may be a key factor contributing to their resistance to diet-induced atherosclerosis, even in the presence of hypercholesterolemia.
