Effect of bevacizumab on corneal neovascularization in experimental rabbit model

Abstract

Purpose: To investigate the effect of bevacizumab in an experimental rabbit model of corneal neovascularization.

Methods: The right eyes of 24 white New Zealand rabbits were included in a corneal neovascularization model using alkaline burn. They were divided into four groups. Topical bevacizumab was installed three times daily in group 1, 5 mg bevacizumab subconjunctivally every 2 days in group 2, 10 mg bevacizumab subconjunctivally every 2 days in group 3 and 0.2 cc of normal saline in the same way in group 4 (control group). All eyes were treated for 7 days. Then the animals were killed and corneal specimens sent for histopathological analysis. Tear film and aqueous humour samples were obtained to assess vascular endothelial growth factor (VEGF) levels.

Results: Seven days after topical bevacizumab treatment the neovascular index in group 1 was lower than that in the control group (P = 0.028). In groups 2 and 3 the neovascular index was lower 2 days after subconjunctival bevacizumab treatment than that in control group (P = 0.009 and P = 0.009, respectively). In the control group the VEGF level in aqueous humour increased by 66% from day 7 to 14. In groups 1-3 it decreased by 49.80%, 70.20% and 76.44%, respectively (P = 0.043). The VEGF level in tear film of the control group increased by 35.23% from day 7 to 14, which was not significant (P = 0.893), while in groups 1-3 it decreased by 57.26%, 34.59% and 67.97%, respectively, which was only significant in groups 1 and 3 (P = 0.043).

Conclusions: Subconjunctival 5 mg/mL bevacizumab is effective in reducing corneal neovascularization in animal models and in reducing VEGF levels. Further research is needed to assess the potential side effects and minimal effective dose.