Diabetes mellitus and the rabbit corneal epithelium

Diabetes mellitus has been shown to be a factor in the development of corneal epithelial abnormalities in stressed human eyes, but the biochemical basis for this is not known. To see if sorbitol pathway activation might be involved, ocular surface epithelial healing rates and metabolites of the glycolytic and sorbitol pathways were measured in alloxan-diabetic rabbits. As in humans, corneal epithelial healing rates were not decreased in the diabetic rabbits, suggesting that the rabbit may be an appropriate model for human disease. Increased levels of glucose, glycogen, and sorbitol were found in the diabetic corneal epithelium compared with normal. However, the sorbitol accumulation only mounted to 1.0 mOsm/L of tissue water, which implies that osmotic damage secondary to corneal epithelial cell sorbitol accumulation might not be a significant factor in corneal epithelial abnormalities of diabetes.