Aldose reductase, diabetes, and thickening of the retinal inner limiting membrane.

Capillary basement membrane thickening is typical of the diabetic retina, and aldose reductase appears to be involved since a diabetic-like thickening can be induced by galactose feeding and prevented with aldose reductase inhibitors. Because aldose reductase is present in the Mueller's cells, studies were undertaken to determine if thickening of the retinal inner limiting membrane, which is the basement membrane of these cells, can be induced by long-term galactose feeding and be prevented with an aldose reductase inhibitor. Weanling male, Sprague-Dawley rats were given a 50% galactose diet with or without an aldose reductase inhibitor (0.04% tolrestat, Ayerst). Quantitative computer planimetry on electron micrographs demonstrated a significant galactose-induced thickening of the inner limiting membrane which was prevented by the aldose reductase inhibitor. The results were consistent with the notion that basement membrane thickening is involved in diabetic retinopathy and can be delayed or prevented with aldose reductase inhibitors.