[Effects of oxidized low density lipoprotein and very low density lipoprotein on the expression of MCP-1 by monocytes].

Monocyte chemoattractant protein-1 (MCP-1) is a potent chemotatic factor for monocytes. This study aimed at examination of the effects of oxidized low density lipoprotein (OX-LDL) and oxidized very low density lipoprotein (OX-VLDL) on the expression of MCP-1 mRNA and protein by monocytes. The guanidinium isothiocyanate method was used to extract total RNA from monocytes which were exposed to LDL, OX-LDL, VLDL and OX-VLDL for 24 hours respectively and the monocyte derived conditioned media collected. MCP-1 mRNA expression in monocytes was examined by slot blot and Northern blot analysis using a gamma 32P-end-labelled 35 mer oligonucleotide probe of MCP-1. Meanwhile, MCP-1 protein in the conditioned media was examined by use of sandwich ELISA. It was found that monocytes from human peripheral blood can express MCP-1 mRNA and protein after 24 hours incubation at 37 degrees C and the expression of MCP-1 mRNA and protein was markedly increased by a 24 hour exposure to OX-LDL and OX-VLDL, whereas the expression of MCP-1 mRNA and protein was only sightly increased when exposed to LDL and VLDL. It is concluded that monocytes can express MCP-1 that induce additional monocyte migration into the subendothelial space, and that OX-LDL and OX-VLDL enhance this function by inducing stronger MCP-1 expression in monocytes.