Vitamin C supplementation could reverse diabetes-induced endothelial cell dysfunction in mesenteric microcirculation in STZ-rats

This paper was aimed to study whether vitamin C supplementation reverses the diabetes-induced endothelial cell dysfunction occurred in streptozotocin (STZ)-rats or not. The animals were divided into four groups: control and diabetes rats (DM, using iv. injection of 50 mg/kg.bw STZ), and two DM rats treated with vitamin C (1 g/l) starting on day 2 (DM + VitC_day2) and week 6th after STZ-injection (DM + VitC_6wks). The mesenteric microcirculation was observed using fluorescence videomicroscopy. Based on the recorded videoimages, microvascular responses to acetylcholine (Ach; 10–5 M) and number densities of leukocyte adhesion in venules were evaluated using the Global Lab II image software. In DM group, blood glucose and glycosylated hemoglobin were significantly increased, while the body weight and plasma vitamin C levels were decreased significantly compared to their controls. Ach-induced vasodilation was decreased, while the number of leukocyte adhesion was increased significantly compared to their controls (p<0.01). These abnormalities induced by DM were prevented by supplementation of vitamin C in DM + VitC_day2 group. Six-weeks delayed treatment of vitamin C (DM + VitC_6wks) demonstrated increase in the Ach-induced vasodilation with significant decrease in the leukocyte adhesion. It was indicated that vitamin C supplementation could reverse diabetes-induced endothelial cell dysfunction in mesenteric microcirculation.