Inhibition of corneal neovascularization after alkali burn: comparison of different doses of bevacizumab in monotherapy or associated with dexamethasone

Abstract

To compare the effects of different doses of bevacizumab with both saline and dexamethasone on inflammatory angiogenesis in the rat cornea induced by small chemical lesions. Corneal chemical cauterization was performed on 24 rats. Animals were divided randomly into six groups and received a daily subconjunctival injection for 7 days of: balanced salt solution 0.1 mL or dexamethasone phosphate 4 mg/day or bevacizumab 2.5 mg/day, 3.75 mg/day, 5.0 mg/day or bevacizumab 5.0 mg/day + dexamethasone phosphate 4 mg/day. Clinical examination under slitlamp was performed daily for 7 days to evaluate corneal opacity and vessel size evolution. Computer assisted quantitative image analysis was used to measure the total corneal area covered by neovascularization. At final examination, the dexamethasone, bevacizumab 5.0 mg/day and dexamethasone + bevacizumab groups showed a significant lowering in corneal opacity score as compared with control (P = 0.024, P = 0.006 and P = 0.013, respectively). Also, a significant reduction on new vessels size score was observed. Surface of corneal neovascularization was significantly reduced in dexamethasone, bevacizumab 5.0 mg/day and dexamethasone + bevacizumab groups compared with control (P =0.045, P = 0.047 and P = 0.044, respectively). Our study demonstrates the ability of a 5.0 mg/day bevacizumab subconjunctival injection, in monotherapy or associated with dexamethasone, to cause a short-term involution of corneal neovascularization after corneal alkali burn. Combination of both of these treatments may have advantages to monotherapy approaches.