Regulation effect of quercetin on cholesterol influx and efflux from RAW264.7 macrophage

Objective To investigate the effects of quercetin on cholesterol accumulation and cholesterol flow in RAW264.7macrophages and explore the potential mechanism underlying its anti-atherogenic activity. Methods The inhibitory effect of quercetin on cholesterol accumulation induced by oxidized low-density lipoprotein(ox-LDL) was assessed by oil red O staining and total cholesterol(TC) specific kits in RAW264.7 macrophages. And the action of cholesterol efflux and influx was tested by fluorescent assays. Cholesterol flow-associated genes expression was detected by real-time quantitative PCR(RT-PCR). Results Quercetin significantly inhibited the cholesterol accumulation. Treatment with quercetin(10 μmol/L) significantly enhanced cholesterol efflux and substantially inhibited cholesterol influx. RT-PCR showed that quercetin significantly increased the m RNA levels of peroxisome proliferator-activated receptor γ(PPARγ),liver X receptor alpha(LXRα),ATP-binding cassette,subfamily A1(ABCA1)and subfamily G1(ABCG1),decreased scavenger receptor(SR)-A1 and SR-A2. Conclusion Quercetin might be a new inhibitor on intracellular cholesterol accumulation. Upregulation of the classical PPARγ-LXRα-ABCA1/ ABCG1 pathway and downregulation of SR-A1 and SR-A2 may participate in its suppressive effect on intracellular cholesterol accumulation.