Effectiveness of bevacizumab and dexamethasone on experimental corneal neovascularization

Corneal neovascularization is defined as formation of new vascular structures on cornea for any reason. Inflammation, infection, degenerative diseases, trauma, and hypoxia can cause formation of new vascular structures on transparent and avascular cornea. Mainly, corticosteroids, nonsteroid antiinflammatory drugs, and VEGF inhibitors are being used for treatment. In this study, our goal is to evaluate and compare the effects of topical dexamethasone, subconjunctival bevacizumab, and topical bevacizumab in experimentally created corneal neovascularization in rabbits.Twenty four male New Zealand rabbits were used in our study. Four groups were designed as control (group 1), topical dexamethasone (group 2), subconjunctival bevacizumab (group 3), and topical bevacizumab (group 4) groups. Chemical burn was created with silver nitrate ? potassium nitrate on the left eye of each subject and related drugs were used for the following ten days for each group. On the tenth day, subjects were sacrificed and corneal neovascularization and apoptosis were evaluated and the groups were compared histopathologically, after hematoxilen eosin, Masson Trichrome, and immunohistochemical staining.Statistically significant decrease was observed in corneal neovascularization in subconjunctival and topical bevacizumab groups. In the dexamethasone group, statistically significant decrease was observed with regard to the control group (p=0,01), but in this group decrease in corneal neovascularization was statistically less significant than bevacizumab groups (p=0,004, p=0,004, respectively). For apoptosis evaluation with TUNEL method, the number of apoptotic cells in bevacizumab groups was significantly less than that in the control and dexamethasone groups (p=0,004, p=0,004, p=0,004, respectively).. There was no statistically significant difference between dexamethasone and control groups for the number of apoptotic cells (p=0,065).As a result, we observed that topical dexamethasone, topical bevacizumab and subconjunctival bevacizumab are effective methods in controlling experimental corneal neovascularization in rabbits, and topical and subconjunctival bevacizumab are more efficient than topical dexamethasone.