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J.E. Mancini, J.O. Croxatto, J.C. Basabe, G. Kusminsky, J. Gallo; Retinal Changes in a Rat Model of Diabetes Type 2 Fed With Fatty Rich Diet . Invest. Ophthalmol. Vis. Sci. 2006;47(13):1732.
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© ARVO (1962-2015); The Authors (2016-present)
There is an increasing incidence of diabetic patients, particularly with diabetes type 2 in which the diet plays an important role. Most animal models of diabetic retinopathy refer to diabetes type 1. We aimed to examine the retina in type 2 diabetic rats with a high–fat diet, and to evaluate the gliotic reaction in astrocytes and Müller cells that seems to be important in the glial–endothelial integrity and balance of the blood–retinal barrier.
Wistar rats were injected with streptozotocin (STZ) at the age of two days with 45 mg/kg ip. in 10 ul citrate buffer. At the age of 8 weeks the animals started to be fed with a high–fat diet. Four diabetic and four control animals were euthanized at the age of 23, 30 and 37 weeks. Cross sections of retinas were analysed by immunofluorescence using glial fibrillary acidic protein (GFAP) antibody. GFAP content was evaluated by Western blot analysis. The integrity of the blood retinal barrier was assessed by Evans blue intravenous injection. Histological changes were examined with optic microscopy.
GFAP was found upregulated in diabetic rats from 23 weeks onwards. Cross sections of the retina revealed that GFAP–positive cells had the morphology and spatial organization of Müller cells in diabetic rats. The alterations in the blood–retinal barrier were confirmed in diabetic rats. Intraretinal teleangiectatic vessels and microaneurisms were histologically identified at 30 and 37 weeks.
This animal model seems to be useful to analyse the effect of diet in the development of diabetic retinopathy and also to study the mechanisms of early retinal damage in type 2 diabetes, especially in cases with the so–called metabolic syndrome.
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