RESUMEN
To examine the ultrastructural changes of rat corneas in streptozotocin [STZ] induced diabetes mellitus and the follow-up insulin treatment. Sprague-Dawley type rats was used for experimental procedures during the period from January to April 2003 at Baskent University, Ankara, Turkey. Rats were studied in 4 groups; group 1: controls, group 2: sham controls [single dose IV sodium citrate], group 3: STZ-induced diabetes mellitus [single dose 45 mg/kg STZ intravenously], group 4: diabetes mellitus + insulin treatment [8 U/day]. We observed degenerative changes in the epithelial layer, stromal keratocytes and endothelial cells in diabetic group. In contrast, the corneal layers have revealed positive alterations in the insulin-treated group. The statistical analyses showed significant narrowing in the epithelial layer in the diabetic group [p=0.002], whereas thickening was observed in the epithelial basement membrane and Descemet's membrane [p=0.002]. It was determined that diabetes mellitus causes degenerative changes in cornea, which are positively influenced by short-term insulin treatment