The effect of long-term supplementation of vitamin C on leukocyte adhesion to the cerebral endothelium in STZ-induced diabetic rats.

The effect of long-term supplementation of vitamin C on leukocyte adhesion to the cerebral endothelium was investigated in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in male Wistar Furth rats by intravenous injection of STZ. The vitamin C, ascorbic acid, was supplemented with drinking water (1 g/l). The rats were divided into control and diabetic groups without or with supplementation of vitamin C. The cerebral microcirculation was directly observed through a cranial window after different periods (12, 24 and 36 weeks) of vitamin C supplementation, using fluorescence videomicroscopy. Leukocyte adhesion to the venular endothelium was examined by labeling leukocytes with rhodamin 6G. The number density of adherent leukocytes in STZ-diabetic rats was increased significantly, compared with control rats. This increase in leukocyte adhesion was prevented by the long-term supplemented vitamin C. It was suggested that the antioxidant effect of vitamin C might be responsible for the prevention of leukocyte adhesion in diabetes mellitus.