Abstract
Purpose: :
to compare the immunohistochemical expression of TNF-α and VEGF peptides in the retina of three rat models of experimental diabetes.
Methods: :
Type 2 diabetes models were constituted by two groups of four male Wistar neonatal rats that received an intraperitoneal injection of 90 mg/kg and 45 mg/kg streptozotocin (SZT) at day 2 of life, respectively. Rats with lower doses of STZ were fed by a high fat diet (HFD) from week 8 onwards. Type 1 model was made up of adult male rats treated with an intraperitoneal injection of 45 mg/kg STZ. All animals, including control non-diabetic group, were sacrificied at 37 weeks of diabetes. Retinas were processed and analysed by immunohistochemical techniques using antibodies against TNF-α and VEGF peptides.
Results: :
TNF-α and VEGF peptides expression were higher in diabetic animals than in controls. All diabetics had a positive immunoreactivity of TNF-α in the fiber layer, while type 1 and type 2 diabetic rats without HFD also showed immunoreactivity in the outer plexiform layer and in the RPE. VEGF expression was observed in the fiber layer of all diabetic animals and in the inner plexiform layer of Type 1 and Type 2 diabetic rats with HFD.
Conclusions: :
Differences in the expression of these peptides involved in inflammation and ischemia may contribute to better understand the mechanisms of diabetic retinopathy in type 1 and type 2 diabetes.
Keywords: diabetes • diabetic retinopathy • ischemia