氧化型低密度脂蛋白经血凝素样氧化型低密度脂蛋白受体1途径诱导血管内皮细胞损伤

Oxidized Low Density Lipoprotein Induced the Injury of Endothelial Cells Via Lectin-Like Oxidized Low Density Lipoprotein Receptor-1

探讨氧化型低密度脂蛋白致血管内皮细胞损伤的作用 ,并从血凝素样氧化型低密度脂蛋白受体 1的途径探讨损伤作用的机制。用1 2 5I标记的氧化型低密度脂蛋白进行放射性配基结合实验及配基竞争性抑制实验检测培养的人脐静脉内皮细胞中存在的特异性氧化型低密度脂蛋白受体 ,2 ,4 二硝基笨肼法测定乳酸脱氢酶活性 ,台盼兰染色、相差显微镜下观察细胞的形态学变化并计数细胞的存活率。结果发现 ,人脐静脉内皮细胞膜上存在与氧化型低密度脂蛋白高亲和力的结合位点 ,Scatchard分析Kd为 38.4± 18.8mg L、Bmax为 181.5± 5 5 .5ng 10 6 cells。氧化型低密度脂蛋白与人脐静脉内皮细胞作用 2 4h ,随着氧化型低密度脂蛋白剂量的增加 ,不仅显著增加人脐静脉内皮细胞释放乳酸脱氢酶的量 ,而且使人脐静脉内皮细胞的存活率下降 ,血凝素样氧化型低密度脂蛋白受体 1受体阻滞剂聚肌苷酸和爱兰苔胶可以阻断氧化型低密度脂蛋白的上述损伤作用。结果提示 ,血管内皮细胞表达氧化型低密度脂蛋白受体血凝素样氧化型低密度脂蛋白受体 1,氧化型低密度脂蛋白诱导对血管内皮细胞的损伤作用可能是通过血凝素样氧化型低密度脂蛋白受体 1的受体途径。

Aim To explore the injured effects of endothelial cells by oxidized low density lipoprotein and its mechanism via lectin-like ox-LDL receptor-1. Methods The specific ox-LDL receptor of cultured umbilical vein endothelial cells (hUVEC) was examed by their binding of 125 I-labeled ox-LDL and by the inhibiting effects of competitors on ox-LDL binding to Lectin-like ox-LDL receptor-1 (LOX-1). Lactate dehydrogenase (LDH) was determined by the method of 2,4-dinitryl-benzohydrazine. Cell viability were detected by trypan blue dye and observed under phase-difference microscope. Results hUVEC membrane was observed to possess a high-affinity ox-LDL binding site (Determined by Scatchard plot, its Kd is 38.4±18.8 mg/L and Bmax is 181.5±55.5 ng/10 6cells). Incubation of hUVEC with ascending dose of ox-LDL for 24 hours. The ascending doses of ox-LDL significantly increase LDH leakage into culture media (from 0.111±0.012 ku/g protein to 0.770±0.044 ku/g protein). Accordingly, viability of hUVEC decrease in response to ox-LDL (from 95.6%±3.8% to 80.7%±4.9%). The effects of ox-LDL is blocked partially by LOX-1 chemical blockers, polyinosinic acid and carrageenan. Conclusion hUVEC possess endothelial receptors for ox-LDL (LOX-1). Ox-LDL-mediated injury to hUVEC may be induced by LOX-1.