Abstract
Abstract: :
Purpose:: Little is known about the cellular events triggered by diabetes in the retina or the process underlying diabetic microangiopathy. Developing a reliable animal model is a crucial part in obtaining this information. Currently, most studies are performed in streptozotocin-induced diabetic rats, which is a good model for type-1 diabetes. No good animal model is yet available for the study of diabetic retinopathy in type-2 diabetes. Our purpose was to Determine if the newly inbred Cohen Diabetic rat, an experimental model reminiscent of type-2 diabetes in humans, can serve as a model for the study of diabetic retinopathy. Methods:: Male Cohen Diabetic sensitive rats (CDs) from the newly inbred colony in Ashkelon were provided either regular chow (RD) or a high-sucrose copper poor diabetogenic diet (HSD). One group was followed for 6 months, and another for a total of 12 months. Upon termination of the study, the animals were sacrificed and their eyes were removed and fixed with a formaldehyde-gluteraldehyde mixture. Blocks were sectioned and stained with hematoxylin and eosin. Sections from the posterior pole of the retinae were examined by light microscopy. The retinal thickness and architecture were compared in CDs fed HSD (which invariably develop diabetes) to those of CDs fed RD (which do not develop diabetes). Results: At 6 months, the retinae of CDs provided HSD (n=6) and RD (n=6) were entirely normal. At 12 months, however, severe retinal atrophy was found in the diabetic CDs fed HSD (n=4), with only remnants of the retinal photoreceptors and ganglion cells and loss of all the inner nuclear and outer nuclear layer cells; retinae of CDs red RD (n=3) were entirely normal. Conclusion: : Diabetes induced by the diabetogenic diet results in severe retinal atrophy in the Cohen Diabetic sensitive rat. The retinal changes develop between 6 and 12 months after initiation of the diabetogenic diet and the appearance of diabetes. The Cohen Diabetic rat thus appears to be a highly suitable experimental model for studying the evolution of diabetic retinopathy in type 2 diabetes.
Keywords: 388 diabetic retinopathy • 506 pathology: experimental