Inhibitory effects of extracellular cholesterol and lipopolysaccharide on cellular cholesterol efflus / 中国组织工程研究

ABSTRACT

BACKGROUND:Cholesterol is closely linked to the occurrence and progression of atherosclerosis. Current approaches to study celular cholesterol dynamics have their own limitations. OBJECTIVE: To measure the cholesterol efflux rate of RAW 264.7 mouse macrophages by BODIPY-Cholesterol labeling and to explore the effects of extracelular cholesterol and lipopolysaccharide on the cholesterol efflux rate. METHODS:RAW 264.7 cels were cultured in vitro with DMEM containing 10% fetal bovine serum, and labeled with BODIPY-Cholesterol for 1, 2, 4, 8 hours. Then, the cels were rinsed with serum-free DMEM and inoculated for 6, 12, 24, 48, 96 hours to optimize the labeling time and incubation time. We measured and compared the cholesterol efflux rates after cultured cels were treated with cholesterol, lipopolysaccharide, human sera with high cholesterol or human sera with normal cholesterol. RESULTS AND CONCLUSION: The best labeling time for BODIPY-Cholesterol was 2-8 hours. Cholesterol efflux rates were gradualy decreased after the cels that were labeled for 2 hours were incubated with increasing concentrations of cholesterol (0.1, 0.5, 2.5 mmol/L,P< 0.01). Treating cels with lipopolysaccharide also decreased the cholesterol efflux rate (P < 0.05). Furthermore, the cholesterol efflux rate was decreased after cels were treated with human sera with high cholesterol (P< 0.05). These findings indicate that BODIPY-Cholesterol can be used to measure celular cholesterol efflux rate and to study the effects of extracelular cholesterol and lipopolysaccharide on the cholesterol efflux rate.