Inhibition Of Experimental Corneal Neovascularization In Rabbits By Subconjunctival Bevacizumab (Avastin)

Objective:To evaluate the effect of subconjunctival bevacizumab on experimental corneal neovascularization(CNV) in rabbits and provide the evidences of clinical application.Methods:The right eyes of 54 White New Zealand rabbits were chemically cauterized with 1mol/L NaOH and they were randomly divided into three groups. Eighteen eyes (group A) received subconjunctival injection of bevacizumab(2.5mg,0.1 mL) immediately after cauterization. Eighteen eyes(group B) received subconjunctival injection of bevacizumab (2.5mg,0.1 mL) 3 days after cauterization. Eighteen eyes(group C) were the control group. The angiogenesis and inhibition of corneal neovascularization were detected respectively by measuring the length and the area of CNV under slit lamp microscopy everyday. Histopathology and corneal confocal microscope were used to detect the corneas at 7days,14days and 28 days after corneal cauterization.Results:The occurrence of CNV in group A was (5.9±0.8) d, group B (3.5±0.6)d, and group C (3.4±1.1)d. Compared with the control group, the CNV occurrence was significantly delayed in group A. No significant difference in the occurrence time of CNV was found between the control group and group B (P=0.068). The CNV areas of group A and group B were smaller than in control group at different time point, and the difference has statistical significance(P<0.05). At the same time, the number of inflammatory cells of group C were much more than group A and B with statistical significance (P<0.05). Inflammatory cells, blood vessels and scars in corneal stroma were identified by corneal confocal microscope. The fibrous structures and scars in corneal stroma of treatment groups were slightly less than control group. The areas of CNV had close relationship with the number of inflammatory cells (P<0.05)Conclusions:subconjunctival injection of bevacizumab can sufficiently decrease the number of inflammatory cells in the cornea after chemical cauterization, improve the microenvironment of injured corneal stroma and accelerate the cornea wound healing, which eventually to inhibit the growth of corneal neovascularization. The anti-neovascular effect of bevacizumab is higher if the injection is performed at the early stage of corneal angiogenesis.