Proliferative retinopathy and neovascularization of the anterior segment in female type 2 diabetic rats

Background: To examine the presence of diabetic retinopathy in a female rat model of type 2 diabetes fed on a high-fat diet (HFD). Methods: Wistar rats were injected with streptozotocin (STZ) at the age of two days and fed on an HFD from eight weeks onwards. Five diabetic animals were euthanized at 110 weeks of disease, together with a control group of age-matched, non-diabetic animals. A group of diabetic animals at 57 weeks of disease was included for comparison. Cross sections of the rats' corneas, iris and retinas were histologically examined and analysed by immunohistochemistry and immunofluorescence, using glial-fibrillary-acidic-protein (GFAP), the vascular endothelial growth factor (VEGF) and the Von Willebrand factor (vWF). The trypsine digestive technique was used for the pericytes count. Results: Neovascularization was only found in the retinas, irises and corneas of the diabetic animals of 110 weeks of disease. There was also a significantly lower number of pericytes in these animals than in the controls. Conclusion: The female rat model of type 2 diabetes fed on an HFD may prove useful in evaluating the mechanisms involved in diabetic retinopathy, together with strategies to reduce its severity.