氧化型低密度脂蛋白在人外周血单核巨噬细胞中的代谢

Metabolism of Oxidized Low Density Lipoproteins by Human Peripheral Monocyte-Macrophages

为探讨氧化型低密度脂蛋白在人外周血单核巨噬细胞中的代谢及其致动脉粥样硬化的机制，使用放射配基法观察了两种低密度脂蛋白在单核巨噬细胞中的代谢情况，并测定了细胞内胆固醇含量的变化。结果发现，人外周血单核巨噬细胞通过受体途径代谢低密度脂蛋白。该受体可饱和，最大结合量（Bmax）为274μg／g细胞蛋白，解离常数为35.7mg／L。低密度脂蛋白经氧化修饰后，人外周血单核巨噬细胞对其结合、摄取和降解均显著增加；与氧化型低密度脂蛋白共同孵育的人外周血单核巨噬细胞内总胆固醇含量明显高于低密度脂蛋白组。以上结果提示，低密度脂蛋白经氧化修饰后在人外周血单核巨噬细胞内的代谢途径发生改变并导致细胞内总胆固醇的堆积，促进了动脉粥样硬化的发生。

Aim In order to elucidate the role of oxidized low density lipoproteins (OLDL), we have examined the metabolism of OLDL in macrophages and the effect of OLDL on the total cholesterol content in macrophages.Methods The metabolism of low density lipoprotein (LDL) and OLDL in macrophages was assessed with the radio-receptor assays.Results Human macrophage metabolized LDL by a receptor pathway with 390. 6 μg/g cell protein of the Bun and 17. 5 mg/L of kd. The receptor Pathway exhibited satuative kinelies. The metabolism of OLDL was different from LDL. The binding internalization and degradation of OLDL by macrophages increased significantly as compared with the LDL. The total cholesterol content in macrophages incubated with OLDL was also higher than that of cells incubated with native LDL.Conclusion OLDL was metabolized by macrophages with different pathway from LDL and may lead to the formation of foams.