Pharmacognostic Evaluation of Curcumin on Diabetic Retinopathy in Alloxan-induced Diabetes through NF-KB and Brn3a Related Mechanism

Background: Diabetic retinopathy is one of the most common micro vascular complication of diabetes and involves an abnormal pathology of major retinal pigment epithelium, inter retinal oedema and intraocular neovascularisation where pro-inflammatory proteins including ICAM-1,iNOS and VEGF release by activation of enzyme CaMKII/NF-kB expression Diabetic induced oxidative stress followed by deactivation of Brn3a expression in the retinal ganglionic cells are also early events in pathogenesis of Diabetic retinopathy. These factors are important contributors to the development of clinically significant diabetic retinopathy. Objective: Objective of this study to examine the effect of curcumin with antioxidant and anti-inflammatory properties obtained from Curcuma longa against diabetes-induced retinal vascular damage and its mechanism of action by in-vivo in retinas of rat rendered diabetic by alloxan and in vitro in western blotting and RGC tissue culture. Method: We administered curcumin or saline vehicle to experimental animals daily for 12 weeks. Vascular permeability, expression of CaMK II/NF-kB, Retinal morphology and neuropathic change of the retinal ganglion cells were investigated. Results: As an anti-oxidant, curcumin raised Retinal Ganglionic cells by increasing Brn3a expression during oxidative stress condition and subsequently decreased the expression of inflammatory mediators such as VEGF, iNOS and ICAM-1 as an anti-inflammatory agent by inhibiting CaMKII and NF-kB expression. Conclusion: Curcumin, a common food additive has beneficial effects in experimental studies of diseases that are characterised by increased oxidative stress and inflammatory reactions. It appears to be a useful adjunct therapy to possibly inhibit the progression of retinopathy, sight threatening complication faced by diabetic patients.