The Effect of Glycemic Control and Renin Angiotensin System Inhibition on Proliferative Diabetic Retinopathy in Streptozotocine Induced Diabetes: A Controlled Study of Insulin and ACE Inhibitor

Abstract

Renin-Angiotensin-Aldosteron System, by causing microvascular changes, has an important impact on the pathogenesis of diabetic retinopathy. Drugs inhibiting Angiotensin Converting Enzyme (ACE) have a potential effect on improving neovascularization at retina. In this study, we aimed to determine the probable effect of an ACE inhibitor, enalapril, on the neovascularization at the rat retina in an experimental model of diabetes compared with insulin treatment. Twenty six Wistar rats were included in the study. Streptozotocine was injected into 18 Wistar rats. After a four-week period of diabetes, the rats were separated in to three groups. No medication was given to the first group. Subcutaneous insulin was given to the second group, and oral enalapril to the third group, for seven days. Eight rats were used as the diabetic control group with no procedure. At the end of one week of therapy, the globes were removed and the number of blood vessel profiles which is indicator of neovascularisation under the internal limiting membrane were counted. The difference between groups was investigated statistically. The number of blood vessel profiles was significantly lower in the control rats than in the streptozotocine injected groups (p<0.001). The number of blood vessel profiles was lower in the enalapril group than in the no treatment group but was not statistically significant (p>0.05). The number of blood vessel profiles was significantly lower in the insulin group than the no treatment group (p<0.01). Insulin and good glycemic control are more effective than the ACE inhibitor enalapril in the treatment of diabetic proliferative retinopathy. © 2010 OMU All rights reserved.