An Experimental Study of Anti-angiogenesis Effects of Doxycycline on Corneal Neovascularization in Rats Induced by Alkali Injury

[Objective]The purpose of this series of experiments was to test whether systemic applied doxycycline could suppress corneal neovascularization (CNV) after alkali injury.[Methods] Alkali injury was induced on day 0 by application of 1 mol/L NaOH to right eyes of S-D rats (n=42) for 40 s. All animals were randomly assigned to treated group and control group, each consisting of twenty-one eyes. Treated group received systemic doycycline once daily in 30 mg/kg dosage during days 1-35. Control group received systemic vehicle once daily also. Biomicroscopic features including corneal edema, epithelial defect, characteristics of anterior segment, and neovascularization were measured on 3 d, 7 d, 14 d, 21 d, 28 d, and 35 d. The area and inhibitory rate of CNV was calculated.[Results] The vessel meshworks of corneal limb were dilated and congested on the first day, then CNV began to invade cornea on day 3, and reached to its developmental peaks between 7d and 14d, lastly, CNV started to regress in 14-21 days after alkali injury. Significant difference (P0.05) in the area of CNV, average length of CNV and corneal edema was found respectively between control group and treated group (P0.05). The inhibitory rate of CNV ranges from 35.8% to 53.3% and increases with time prolonging. [Conclusions] Doxycycline has prominent inhibitory effectiveness on corneal angiogenesis induced by alkali injury.