To investigate whether low density lipoprotein (LDL), very low density lipoprotein (VLDL), oxidized LDL (OX-LDL) and VLDL (OX-VLDL) could induce the cultured human endothelial cells (ECs) to express high levels of macrophage inflammatory protein lα (MIP-lα) and vascular cell adhesion molecule 1 (VCAM-1) mRNA. LDL and VLDL were isolated from normal human blood donors by density gradient ultracentrifugation and oxidized by Cu2+. The cultured human umbilical vein ECs were incubated with native LDL, VLDL, OX- LDL and OX-VLDL respectively, for 24 h, and in the control group no lipoproteins were added. Total cellular RNA was extracted from the cultured ECs by guanidinium isothiocyanate method. The expression of MIP-lα and VCAM-1 mRNA was detected by dot blotting analysis with two probes of digoxigenin-labeled MIP-lα and VCAM-1 cDNA fragments. The results showed that the cultured ECs could express MIP-lα and VCAM-1 mRNA. Incubation of ECs with LDL and VLDL led to a slightly increased expression of MIP-1α and VCAM-1 mRNA, whereas exposure of ECs to OX-LDL and OX-VLDL resulted in a significant increase ofMIP-1α mRNA expression that was 3. 2- and 2. 5-fold as much as that of the control group, respectively, and the VCAM-1 mRNA expression was increased as well, which was 2. 6- and 2. 17-fold as much as that of the control group respectively. It was suggested that lipoproteins especially oxidized lipoproteins could induce the expression of MIP-1α and VCAM-1 mRNA in ECs, which might play an important role in the recruitment of monocytes into the intima.%为探讨天然及氧化修饰脂蛋白对培养的内皮细胞MIP-1α及VCAM-1mRNA表达的作用，取正常人新鲜血液，用超速梯度离心法分离出LDL和VLDL后，加Cu2+使之氧化，成为OX-LDL和OX-VLDL。培养人脐静脉内皮细胞(EC)，待其汇合后分别加入LDL、OX-LDL、VLDL、OX-VLDL，使其终浓度为25μg／m1，对照组不加脂蛋白。培养24h后，收集EC，用异硫氰酸胍法提取其总RNA，用地高辛标记的MIP-1α和VCAM-1 cDNA探针进行斑点杂交。结果显示，培养的EC能表达MIP-1α和VCAM-1 mRNA，当其暴露于LDL和VLDL后，其MIP-1α和VCAM-1 mRNA表达轻度增加，而当EC暴露于OX-LDL和OX-VLDL后，其MIP-1α mRNA表达水平明显增高，分别为对照组的3．2倍和2．5倍；VCAM-1 mRNA的表达分别为对照组的2．6倍和2．17倍。提示脂蛋白，特别是氧化修饰的脂蛋白，可促进EC表达MIP-1α和VCAM-1 mRNA，在动脉内膜单核细胞的募集中起重要作用。
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