The effects of sorbinil, an aldose reductase inhibitor, on the corneal endothelium in galactosemic dogs

Wide-field specular microscopy was used to examine the central corneal endothelium of age- and sex-matched beagle dogs fed for up to 32 months either normal control diets containing 30% nonnutrient filler (13 dogs) or diets containing 30% galactose with (13 dogs) or without (12 dogs) concomitant treatment with the aldose reductase inhibitor, sorbinil. Computerized morphometric analysis of the endothelial cells indicated that a significant decrease in cell density and increase in mean cell area occurred in untreated galactose-fed dogs after 32 months of feeding compared with the normal controls. However, no significant difference could be observed in similar galactose-fed dogs treated with sorbinil. No significant difference in the coefficient of variation of the area, or percent hexagonality of the endothelial cells, or the corneal thickness could be observed in any group. These findings demonstrated that endothelial abnormalities were present in the cornea of the galactose-fed dogs which were similar to those reported for diabetic dogs, rats, and patients and that these changes can be prevented by the concomitant administration of an aldose reductase inhibitor. These findings suggest a role for aldose reductase in the abnormalities noted in the corneal endothelium in diabetes and galactosemia.