Vascular endothelial growth factor in corneal neovascularization of rats

Objective To study the role of vascular endothelial growth factor(VEGF) in corneal neovascularization after cautery with alkali. Methods Corneal neovascularization was induced by NaOH cauterizing the surface of cornea in 40 rats. Slit-lamp biomicroscopy revealed a gradual development of corneal neovascularization.Animals were grouped and sacrificed at 1 d,4 d,7 d,14 d,21 d after CNV respectively.The corneas were enucleated for histopathological examination;Polymorphonuclear leukocyte(PMN) was counted;The expressions of VEGF was studied by immunohistochemistry,and the results was analyzed by picture quantitative analysis techniques.Results The histopathological study showed the number of PMNs was 0.500±0.629 in the untreated corneal group.PMNs increased gradually and were the highest in CNV 7 d group and began to decrease after 7 days;Immunohistochemistry demonstrated:the positive expression of VEGF in CNV progressed gradually,and involved the entire cornea on the 7 days post-treatment.After 7 days the expression decreased following the decrease of inflammatory cells,however,21 days post treatment the positive expression was not found.Conclusion The positive expression of VEGF in CNV increases gradually,and is paralleled with the corneal inflammatory reaction.Furthermore PMNs may play key roles in CNV.