Prevention of corneal neovascularization: comparison of different doses of subconjunctival bevacizumab with its topical form in experimental rats.

摘要

Background: To compare the effect of different dosages of subconjunctival bevacizumab with its topical administration on preventing the development of corneal neovascularization (CNV) in a rat model of corneal chemical injury. Methods: Neovascularization was induced by pressing a 2-mm diameter alkaline-coated applicator on the central cornea of the right eye of 50 anesthetized male rats. Immediately after cauterization, rats were divided randomly into 5 groups. Groups 1-4 received a subconjunctival injection of 0.02 ml of normal saline (control) or 1, 5 and 25 mg/ml of bevacizumab, respectively. In the fifth group, topical bevacizumab was instilled daily for 7 consecutive days. After 7 days, digital photographs of the cornea were taken and the area of the neovascularized cornea was calculated. Results: Analysis of digital photographs showed that, compared with the controls, a single subconjunctival injection of at least 0.1 mg of bevacizumab (5 mg/ml) - immediately after corneal cauterization - effectively decreased CNV after 7 days. Injection of 25 mg/ml of bevacizumab in the fourth group increased the avascular area more than twofold, compared with the saline-treated group (32.2% compared with 15%, p < 0.001). This difference between groups 4 and 2 was statistically significant (p = 0.04). Although topical delivery of 25 mg/ml bevacizumab was effective to inhibit CNV (p = 0.004), the results were similar to those of the third group. Qualitative microscopic evaluation of the cornea was compatible with the gross findings, as bevacizumab-treated groups had less intense corneal vessel channels and inflammation. Conclusion: Both subconjunctival and topical bevacizumab can prevent CNV in rats.