The effect of methotrexate on corneal neovascularization in rabbits

Purpose: To determine the efficacy of topical application and subconjunctival injection of methotrexate in the treatment of corneal neovascularization using a rabbit model. Methods: Corneal neovascularization was induced with suturing in 12 rabbits (24 eyes). One week after suturing, 12 rabbits were divided into 3 groups of 4 rabbits each. One group was treated with topical methotrexate 2 mg/mL, a second group with topical methotrexate 4 mg/mL, both 4 times a day, and the third group with a subconjunctival injection of methotrexate 2 mg/mL (0.1 mL). Control rabbits received a balanced salt solution instead of methotrexate. The area of corneal neovascularization was measured using light microscopy, 1 week and 2 weeks after initiation of the treatment. The concentrations of vascular endothelial growth factor and interleukin-6 in corneal tissue were measured 2 weeks after initiation of the treatment. Results: The area of neovascularization was significantly reduced in the treatment groups compared with the control group (P < 0.05). No significant difference was found in the area of neovascularization between the groups treated with the 2 doses of topical methotrexate. The concentrations of vascular endothelial growth factor and interleukin-6 were significantly lower in the treatment groups compared with the control group (P < 0.05), but no difference was observed among the treatment groups. The corneal epithelium, stroma, and endothelium showed a normal appearance. Conclusions: Topical and subconjunctival methotrexate application may be useful for treating corneal neovascularization, but further study regarding dosage, route of administration, and indications for methotrexate should be performed in the future.