Abstract
Purpose: :
recent studies demonstrated that topical application of anti-Nerve growth factor (NGF) antibody to the eye enhanced the expression of Vascular endothelial growth factor (VEGF) in the retina. It is well known that VEGF is increased in diabetic retinopathy and its complications, such as retinal neovascularization and macular edema. The present experiment is directed to prove that conjunctival instillation of NGF can reduce retinal VEGF levels in an animal model of diabetes.
Methods: :
diabetes was induced in adult male rats with injections of streptozotocin. Diabetic rats were treated twice daily with 20 ul of purified NGF at a concentration of 200ug/ml for 10 consecutive days. Control diabetic rats were treated with saline. The retina, cornea, optic nerve and crystalline lens were collected to measure the presence of VEGF protein using a commercial ELISA assay.
Results: :
VEGF was reduced in the retina of diabetic rats treated with NGF when compared to diabetic controls (158±21 vs. 219±28 pg/mg, p<0.05). Similar changes where noted in the optic nerve tissues. No statistically significant changes were measured in the cornea and lens of NGF-treated rats when compared to controls.
Conclusions: :
our study suggests that NGF may exert a protective action on diabetic retinopathy reducing retinal VEGF levels. Our data reinforce the hypothesis that NGF plays a primary role in the mechanisms governing retinal cell physio-pathology.
Keywords: diabetic retinopathy • growth factors/growth factor receptors • vascular endothelial growth factor