EFFECT OF AN ALDOSE REDUCTASE INHIBITOR ON ABNORMALITIES OF ELECTRORETINOGRAM AND VASCULAR FACTORS IN DIABETIC RATS

The effect of an aldose reductase inhibitor, [5-(3-thienyl) tetrazol-1 -yl] acetic acid (TAT), on the electroretinogram was determined in rat s with streptozotocin-induced diabetes. Laboratory chow containing 0.0 5% TAT was given to rats for 2 months, while other diabetic rats were untreated. Groups of TAT-treated and untreated normal rats were also s tudied. Treatment with TAT produced significant improvement of the ele ctroretinogram. TAT shortened the peak latencies of the b-wave oscilla tory potentials, which were significantly prolonged in untreated diabe tic rats (P <0.0001 vs. untreated normal rats). This was accompanied b y a significant decrease in the retinal sorbitol and fructose concentr ations (by 46.5% and 25.7%, respectively). TAT treatment of diabetic r ats also markedly reduced ADP-induced platelet aggregation and signifi cantly increased the red blood cell 2,3-diphosphoglycerate level, acco mpanied by a marked reduction in sorbitol and fructose concentrations of platelet and red blood cells. There were significant correlations b etween the summed b-wave peak latencies and platelet aggregation or th e 2,3-diphosphoglycerate level in diabetic rats. These findings sugges t that an aldose reductase inhibitor, TAT, has therapeutic value for d iabetic retinopathy.