Minimally modified low-density lipoprotein induces monocyte chemotactic protein-1 expression in vivo and a novel model for monocyte adhesion to arterial intima

Objective To test whether minimally modified low-density lipoprotein (MM-LD L) can stimulate the arterial cells expressing MCP-1 in vivo and thus induc e monocyte adherence to endothelium. Methods An animal model was constructed to study the function of MM-LDL in vivo. MM-LDL (600 mu g/ml) was perfused into a segment of the femoral arter y of rabbits (both ends of which were occluded with removable ligatures). A fter exposure to MM-LDL for 2 h, the arterial segments were taken out 6 or 18 h later. The arteries were subjected to in situ hybridization with S-35- labeled antisense monocyte chemotactic protein-1 (MCP-I) RNA probe and proc essed far scanning electron microscopy. Results The expression of MCP-1 mRNA of the arterial endothelial cells and smooth muscle cells were increased by 60% and 90% 6 h after perfusion and h ad a 3.2 folds and 1.6 folds increase 18 h after perfusion respectively as compared with control (arteries perfused with saline). There was also appar ent monocyte adherence to the endothelium observed by scanning electron mic roscopy. Conclusion MM-LDL can stimulate vascular cells in expressing MCP-I mRNA and enhance monocyte adherence to endothelium in vivo.