高密度脂蛋白对内皮细胞胆固醇流出的影响

目的 研究高密度脂蛋白(HDL)和氧化高密度脂蛋白(OX-HDL)对人脐静脉内皮细胞的三磷酸腺苷结合盒转运体A1(ABCA1)表达和胆同醇流出的影响.方法 体外培养人脐静脉内皮细胞,并分别与100μg/ml HDL或100μg/ml ox-HDL温育24 h.设PBS为对照组.采用RT-PCR、液体闪烁计数法分别检测人脐静脉内皮细胞ABCA1的mRNA水平及细胞内胆固醇流出功能.结果 HDL组及ox-HDL组的ABCA1 mRNA表达水平分别较埘照组增高58%和23%.差异有统计学意义(P<0.05);ox-HDL组较HDL组的胆同醇流出率显著降低(P<0.01).结论 HDL可显著上凋人脐静脉内皮细胞的ABCA1表达并介导内皮细胞胆固醇流出;HDL经氧化修饰后对ABCA1表达的上调作用减弱.引起内皮细胞胆同醇外排障碍,是HDL氧化修饰后促进动脉粥样硬化发展的可能机制之一.

Abstract：

Objective To study the effects of high-density lipoprotein (HDL) and oxidized high-density lipoprotein (ox-HDL) on the expression of ATP-binding cassette transporter A1 (ABCA1) and cholesterol efflux in human umbilical vein endothelial cells (HUVECs). Methods In vitro cultured HUVECs were incubated in the presence of 100 μg/ml HDL or 100 μg/ml ox-HDL for 24 h, using PBS as the negative control. ABCA1 mRNA level and cholesterol efflux rate were determined using RT-PCR and a liquid scintillator, respectively. Results HDL and ox-HDL significantly elevated the level of ABCA1 mRNA by 58% and 23% relative to the control level, respectively (P<0.05). The cholesterol efflux rate in ox-HDL group was significantly lower than that in HDL group (P<0.01). Conclusion HDL increases ABCA1 expression and cholesterol efflux in HUVECs. Oxidative modification of HDL decrease cholesterol efflux by inhibiting the expression of ABCA1, suggesting a possible mechanism of ox-HDL in the pathogenesis of atherosclerosis.

Effects of high-density lipoprotein on the cholesterol efflux from endothelial cells

Objective To study the effects of high-density lipoprotein (HDL) and oxidized high-density lipoprotein (ox-HDL) on the expression of ATP-binding cassette transporter A1 (ABCA1) and cholesterol efflux in human umbilical vein endothelial cells (HUVECs). Methods In vitro cultured HUVECs were incubated in the presence of 100 μg/ml HDL or 100 μg/ml ox-HDL for 24 h, using PBS as the negative control. ABCA1 mRNA level and cholesterol efflux rate were determined using RT-PCR and a liquid scintillator, respectively. Results HDL and ox-HDL significantly elevated the level of ABCA1 mRNA by 58% and 23% relative to the control level, respectively (P<0.05). The cholesterol efflux rate in ox-HDL group was significantly lower than that in HDL group (P<0.01). Conclusion HDL increases ABCA1 expression and cholesterol efflux in HUVECs. Oxidative modification of HDL decrease cholesterol efflux by inhibiting the expression of ABCA1, suggesting a possible mechanism of ox-HDL in the pathogenesis of atherosclerosis.