Abstract
Hyperglycemia plays a more important role in the initiation and development of microangiopathy than in macroangiopathy among diabetes-induced complications. Platelet-endothelium interaction and thrombus formation might be accelerated in diabetic microcirculation. However, few in vivo studies have demonstrated thrombus formation in microcirculation of diabetic animal models. In this study, we conducted a photothrombotic vessel occlusion model in the mesenteric arterioles of normal rats or streptozotocin-induced diabetic rats. A photothrombosis, which is caused by production of active oxygen, was induced under the presence of a photosensitizing dye (Photofrin) and light irradiation. We measured the time from beginning of irradiation to initiation of platelet adhesion (Ti) and the time from beginning of irradiation to vessel occlusion (To). Then we conducted a photochemical platelet adhesion assay using platelets collected from healthy controls or diabetic patients with human cultured endothelial cells treated with normal glucose concentration, high glucose concentration or advanced glycation end products (AGE). We measured the area of platelet adhesion to endothelial cells. The in vivo experimental results showed that Ti and To in diabetic arterioles significantly decreased compared to those in normal arterioles. The in vitro results did not show any significant difference between adhesion of normal platelets and that of diabetic platelets to the cultured endothelial cells. However, platelet adhesion to the cultured endothelial cells treated with high glucose concentration and with AGE increased significantly compared to that with normal glucose concentration. From these results, it can be concluded that platelet-endothelium interaction and thrombus formation are accelerated in diabetic microcirculation.[MVRC 2 (1): 24-32,2008]
