巨噬细胞氧化修饰极低密度脂蛋白及Cu^(2+)修饰的极低密度脂蛋白对单核细胞与内皮细胞粘附的影响

Oxidative Modification of Very Low Density Lipoprotein and its Effects on Monocyte Adherence to endothelial Cells

极低密度脂蛋白(VLDL)与小鼠腹腔巨噬细胞温育24小时和48小时后,其硫代巴比妥酸反应物质值明显高于无细胞对照组,琼脂糖电泳速度也加快,两者一致。结果说明小鼠腹腔巨噬细胞可以氧化修饰极低密度脂蛋白。VLDL在体外用Cu^(2+)修饰后。硫代巴比妥酸反应物质明显增加,琼脂糖凝股电泳速度加快。比较正常的VLDL(n—VLDL)及Cu^(2+)氧化的VLDL(Ox—VLDL)对内皮细胞粘附单核细胞的影响时,发现在所用各种浓度下,Ox—VLDL单核细胞的粘附率比n—VLDL组大得多(P<0.0001),说明VLDL被氧化后明显增加单核细胞与内皮细胞的粘附。

VLDL (200μg Protein/ml)was incubated with MΦ for 24 and 48 hours. The TBARS in VLDL after incubation for 24 and 48 hrs were 10.04±0.77 and 11.25±0.53nmol/mg protein respectively, which were much higher than that of controls (4.60±0.56,7.95±0.66 respectively). The MΦ modified VLDL migrated faster than the controls on agarose electrophoregram. In conclusion, VLDL could be oxidatively modified by MΦ in vitro. It suggests VLDL might be oxidited in Vivo. VLDL is also susceptible to oxidative modification by Cu^(2+) in vitro resulting in an increase in electrophoretie mobility and TBARS in the lipoprotein. Cu^(2+)—Ox—VLDL had the potential ability to increase MC adherence to EC. The effects were concentration dependent. The percentage of MC adherence in n—VLDL group was much less than that in Ox—VLDL group (P<0.001). It suggests that Ox—VLDL plays an important role in MC adherence to EC.