摘要
目的观察氧化低密度脂蛋白对健康人红细胞左旋精氨酸（L-arg）转运的影响。方法用低密度脂蛋白和氧化低密度脂蛋白分别孵育正常人红细胞后将细胞分为对照组、低密度脂蛋白组和氧化低密度脂蛋白组，以^3H标记的L-arg（^3H L-arg）来测定红细胞的L-arg转运。结果低密度脂蛋白对红细胞L-arg转运无明显影响（P〉0．05）。氧化低密度脂蛋白抑制红细胞L-arg转运：氧化低密度脂蛋白组氧化低密度脂蛋白25、50、100mg／L3个浓度总摄入的最大转运速率（Vmax）值分别较对照组降低33％、27％、30％（P均〈0.05），亲和力明显减小（米氏常数值增大，P〈0．05），均有显著性差异，未见明显的浓度-效应依赖关系；与对照组相比，氧化低密度脂蛋白组氧化低密度脂蛋白25、50、100mg／L3个浓度y＋载体介导的L～arg转运的最大转运速率值明显降低，分别降低43％、48％、45％（P均〈0．05），均有显著性差异，亲和力明显减小（米氏常数值增大）；与对照组相比，氧化低密度脂蛋白组通过y＋L载体介导的L-arg转运（最大转运速率值及米氏常数值）均无明显改变（P〉0．05）。结论低密度脂蛋白氧化成氧化低密度脂蛋白后抑制红细胞L-arg的跨膜转运，推测氧化低密度脂蛋白是高脂血症患者红细胞L-arg／一氧化氮途径功能紊乱的重要因素。
Objective To examine the effect of oxidized low density lipoprotein （OX-LDL） on L-arginine transport in human erythrocytes. Methods Isolated human erythrocytes from heathy donors were incubated by LDL and OX-LDL, and the 3 H- L-arginine transport were measured. Results The transport of L-arginine in erythrocytes was not affected by LDL. OX-LDL inhibited the transport of L-arginine in erythrocytes. Compared with controls, the Vmax for the total transport of L-arginine in erythrocytes incubated by OX-LDL （25,50 and 100 mg/L） decreased by 33%, 27% and 30%, respectively （P〈0.05）. The Vmax for the transport of L-arginine via system y＋in erythrocytes incubated by OX-LDL （25, 50 and 100 mg/L） decreased by 43%, 48% and 45 %, respectively （P〈0.05）. Km values increased for both groups （P〈0.05）. The Vmax and Km value for the transport of L-arginine via system y＋L were not changed in erythrocytes incubated by OX-LDL. Conclusions OX-LDL inhibits L-arginine transport in human erythrocytes. OX-LDL may be an important factor in the disturbance of L-arg-NO path- way in erythroeytes of patients with hyperlipidemia.
