小凹介导氧化低密度脂蛋白跨内皮细胞转运

目的探讨小凹在氧化低密度脂蛋白（ox—LDL）逆向转运中的作用机制。方法用40μg／mLox—LDL处理人脐静脉内皮细胞（hUVEC）不同时间（0、6、12、24h），高效液相色谱法观察细胞内脂质含量变化。用nocodazole阻滞cavolae运动后，荧光倒置显微镜观察FITC标记的氧化低密度脂蛋白受体（Lox-1）在细胞内的定位。将人脐静脉内皮细胞种植于transwell培养系统套3i／1．上层，分别用3种小凹阻滞剂carrageenan、filipin、no—codazole预处理细胞1h后加入40岬l／mLDiI荧光标记的ox—LDL（DiI—ox—LDL）于套皿上层孵育24h，取套皿下层液体用荧光分光光度计测荧光强度值。结果人脐静脉内皮细胞与ox—LDL孵育时，细胞荷脂呈时间依赖性增加。同时ox—LDL导致Lox-1向胞浆聚集，而nocodazole可阻止Lox-1向胞浆的聚集。小凹阻滞剂明显阻滞ox—LDL的跨内皮细胞转运分别达49％、72％和80％。结论内皮细胞可摄取ox—LDL而荷脂，其摄取ox—LDL的受体Lox-1定位于小凹中，小凹在介导ox—LDL的跨内皮细胞转运过程中起运载工具的作用。

Caveolae Mediates Transcytosis of Oxidized Low Density Lipoproteins Across Endothelium

Objective To explore the mechanisms involved in cholesterol transcytosis across endothelial cells and the effects of caveolae in this process. Methods Human umbilical vein Endothelial Cells （ hUVEC ） were incubated with oxidized low - density lipoprotcin （ ox - LDL } （ 40 μg/mL ） for different times （ 0,6,12,24 h ） , lipid content in hUVEC was determined by HPLC. hUVEC were preincubated with or without nocodazole for 1 h, and incubated another 24 h with ox - LDL, and the location of LOX- 1 was observed, hUVEC were planted on a Transwell insert to obtain a tight monolayer and preincubated with carrageenan, filipin, or nocodazole for 1 h, then incubated for another 24 h after addition of DiI labeled ox - LDL（40 μg/mL） , the fluorescence intensity of DiI - ox - LDL that transcytosised up to the bottom reservoir was determi ned. Results hUVEC intra - cellular lipid contents increased with ox - LDL in a time - dependent manner. When hUVEC were treated with ox -LDL, LOX -1 focused in cytoplasm, while nocodazole could abolish ox -LDL＇ s effect. Ox -LDL that transcytosised through hUVEC decreased significantly to 49% , 72% and 80% respectively, after treated with caveolae inhibitors. Conclusions hUVEC can uptake ox - LDL through its receptor, which were located with or within cavoelae, hUVEC is a post - house in ox - LDL translocation through endothelium, and Cavoelae play an important role in this process.