Trans-Chalcone prevents VEGF expression and retinal neovascularization in the ischemic retina

Retinal neovascularization (RNV) is a critical pathological event and a major cause of blindness. Vascular inflammation and oxidative stress have been shown to play a key role in the induction and progression of RNV. Trans-Chalcone-derived flavonoids have been previously shown to be negative modulators of oxidative stress and inflammatory responses as well as tumor angiogenesis. In this study, we characterized the effects of the flavonoid trans-Chalcone in preventing RNV in a model of ischemic retinopathy. Ischemic retinopathy was induced in neonatal mice subjected to oxygen-induced retinopathy. Trans-Chalcone was administered intra-peritoneum at the dose of 25 mg/kg/day. Vascular density was assessed by morphometric analysis of flat mounted retinas stained with Texas red-Isolectin B4. Western blotting analysis was conducted to determine protein levels of vascular endothelial growth factor (VEGF), inter-cellular adhesion molecule 1 (ICAM-1) and the transcriptional activators' signal transducer and activator of transcription 3 (STAT3) and nuclear factor kappa beta (NF-κB). Treatment with trans-Chalcone significantly inhibited RNV in the ischemic retina, as shown by decreased number of neovascular tufts. Trans-Chalcone also blocked ischemia-induced VEGF and ICAM-1 expression and this effect correlated with inhibition of activated STAT3 and NF-κB. Our results show that trans-Chalcone effectively prevents RNV in the murine retina thus suggesting that Chalcone-derived flavonoids may be beneficial in preventing pathological neovascularization in the ischemic retina.