ABSTRACT
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.