OBJECTIVE: Inflammation is one of the initial repair processes after vascular injury. E-selectin facilitates adherence of leukocytes to vascular endothelium at the site of inflammation. Because the role of E-selectin in this process is not fully understood, we studied the role of E-selectin in vascular injury with a flow chamber model and a rat model of carotid artery injury. METHODS AND RESULTS: We established a rat aortic endothelial cell (RAEC) culture system from the aortas of adult male rats. When rat myelomonocytes were suspended in a flow chamber, rolling and adhesion to lipopolysaccharide (LPS)-stimulated RAECs were observed. Cell rolling and adhesion were greatly reduced by addition of anti-E-selectin monoclonal antibody (mAb). We then induced balloon injury in the left carotid arteries of rats. E-selectin expression was enhanced in endothelial cells at adventitial small vessels 7 days after injury. Rats with balloon injury were injected intraperitoneally with anti-E-selectin mAb for 8 days. Inflammatory cell infiltration was reduced by anti-E-selectin mAb treatment at the adventitia at 7 days after injury. This reduction was associated with attenuation of intimal hyperplasia in the rats treated with the mAb. CONCLUSIONS: These data suggest that E-selectin regulates adventitial inflammation through leukocyte adhesion and contributes to the process of intimal hyperplasia after balloon injury.