OBJECTIVE: Postoperative intimal hyperplasia, the major cause of vein graft occlusion, is initiated by endothelial injury. Using a high-magnification scanning electron microscope (SEM), the surfaces of endothelial cells in vein grafts were examined to investigate the protective mechanism of the free radical scavenger edaravone (Radicut, Mitsubishi Tanabe Pharma Co, Japan) against endothelial injury in postoperative intimal hyperplasia. METHODS: In 10 male Lewis rats with a mean (± SD) weight of 495±28 g, a right epigastric vein graft was interposed into the common femoral artery. Five rats received preoperative intraperitoneal administration of edaravone (3.0 mg/kg; edaravone group). The other five received an equal volume of saline preoperatively (sham operation group). Unoperated right epigastric veins were also examined as controls. The vein grafts from each group were examined using an S-800 Hitachi SEM (Hitachi High-Technologies Co, Japan) at ×10,000 to ×20,000 magnification. RESULTS: Unoperated endothelial cells had smooth surfaces. While endothelial cells in the sham operation group had very rough surfaces with platelet adhesion, endothelial cells in the edaravone group had smooth surfaces without platelet adhesion, very similar to unoperated endothelial cells. CONCLUSION: These SEM results showed that edaravone may maintain the smooth surface of endothelial cells. The authors postulate that edaravone suppresses postoperative intimal hyperplasia by alleviating endothelial injury.
OBJECTIVE: Postoperative intimal hyperplasia, the major cause of vein graft occlusion, is initiated by endothelial injury. Using a high-magnification scanning electron microscope (SEM), the surfaces of endothelial cells in vein grafts were examined to investigate the protective mechanism of the free radical scavenger edaravone (Radicut, Mitsubishi Tanabe Pharma Co, Japan) against endothelial injury in postoperative intimal hyperplasia. METHODS: In 10 male Lewis rats with a mean (± SD) weight of 495±28 g, a right epigastric vein graft was interposed into the common femoral artery. Five rats received preoperative intraperitoneal administration of edaravone (3.0 mg/kg; edaravone group). The other five received an equal volume of saline preoperatively (sham operation group). Unoperated right epigastric veins were also examined as controls. The vein grafts from each group were examined using an S-800 Hitachi SEM (Hitachi High-Technologies Co, Japan) at ×10,000 to ×20,000 magnification. RESULTS: Unoperated endothelial cells had smooth surfaces. While endothelial cells in the sham operation group had very rough surfaces with platelet adhesion, endothelial cells in the edaravone group had smooth surfaces without platelet adhesion, very similar to unoperated endothelial cells. CONCLUSION: These SEM results showed that edaravone may maintain the smooth surface of endothelial cells. The authors postulate that edaravone suppresses postoperative intimal hyperplasia by alleviating endothelial injury.