Effect of pyridoxine on the blood-retina barrier in experimentally induced hyperglycemia in rats.

We studied the effects on the blood-retina barrier of pyridoxal S phosphate, the biologically active form of vitamin B6 (pyridoxine), in 23 male Long-Evans rats in which hyperglycemia had been induced by means of intraperitoneal injection of streptozocin. Twelve rats were treated with pyridoxine, and 11 rats served as the control group. Vitreous fluorophotometry was used to quantitatively evaluate the effect of pyridoxine. The procedure was done before and 2 weeks after the induction of hyperglycemia, readings being taken 5 and 60 minutes after injection of the dye. In both groups the mean vitreous fluorescein levels after hyperglycemia was induced were significantly higher than those before hyperglycemia was induced (p less than 0.05). The mean levels before hyperglycemia was induced were not significantly different between the two groups. The mean level 60 minutes after injection of the dye after hyperglycemia was induced was lower in the treated group than in the untreated group, although not significantly so. The incidence of lens opacities at 5 weeks was higher in the untreated group than in the treated group (p less than 0.01). We conclude that administration of pyridoxine to hyperglycemic rats for 5 weeks has no significant effect on the permeability of the blood-retina barrier.