Background and Objectives: Diabetic retinopathy (DR) is one of the main causes of blindness and there
is no available treatment for complete cure. This study was planned to evaluate the potential protective
effects of simvastatin in a rat model of DR with special emphasis on endothelial progenitor cells (EPCs).
Methods: Thirty adult male albino rats were equally divided into: Group І (control group), Group II
(diabetic group) and Group III (diabetic/simvastatin treated group). Diabetes was induced by intraperitoneal
injection of streptozotocin (STZ) 50 mg/Kg /rat in 20 adult male albino rats. Simvastatin was administered
as 20 mg/Kg/rat 48 hours after STZ injection via oral route. Body weight and blood glucose levels were
measured weekly for 1 month. Flowcytometry was used to detect circulating endothelial progenitor cells
(EPCs). Retinal specimens were processed for hematoxylin and eosin staining as well as CD31 and
caspase 3 immunohistochemistry. Morphometric analysis included measurement of retinal thickness,
number of ganglion cells, number of CD31 positive cells and area percent of caspase 3 positive immunereaction.
All results were statistically analyzed.
Results: Flowcytometry showed that simvastatin was able to increase the percentage of circulating EPCs
in group III compared to group II. Group II showed histological features of DR, CD 31 immuno-reaction
was comparable to control and caspase 3 immuno-reaction increased significantly compared to control.
Group III showed improved features of DR, significant increase in CD 31 and decrease in caspase 3
immuno-reactivity.
Conclusions: These results suggest that simvastatin has protective effects on DR and might be considered
as promising therapeutic agent for it.