Abstract
Purpose: :
Several reports have recently indicated that topical or local treatment with high concentration of bevacizumab (Avastin) successfully reduced corneal neovascularization in experimental models and in human patients, and thus it may have a therapeutic role in the treatment of corneal neovascularization. The purpose of the current study is to evaluate the effect of different concentrations of topically administered bevacizumab on experimental corneal neovascularization in rats.
Methods: :
Silver nitrate sticks (75% silver nitrate, 25% potassium nitrate) were used to induce chemical cauterization on the center of the corneas of 37 eyes of 37 female Wistar rats. For the following 7 days, 29 eyes were instilled twice daily with bevacizumab drops of different concentrations: 4 mg/ml (n=10), 2 mg/ml (n=9) and 1 mg/ml (n=10), whereas the 8 eyes of the control group received normal saline drops. The magnitude of corneal neovascularization 8 days after cauterization was determined both by clinical evaluation and by blood vessel count from digital photographs of corneal sections stained with Hematoxylin and Eosin.
Results: :
In the eyes treated with all three different concentrations of bevacizumab, the neovascularization was less intense, as compared to the saline-treated control group. However, only in the eyes treated with bevacizumab 4 mg/ml, the difference from the control group was significant (p = 0.000004 for the clinical scoring and p = 0.018 for the blood vessel counting).
Conclusions: :
Topically administered bevacizumab at a concentration of 4 mg/ml significantly reduces the corneal neovascularization following chemical injury in the rat model, while lower concentrations are less effective.
Keywords: cornea: stroma and keratocytes • vascular endothelial growth factor