[The effect of recombinant epidermal growth factor in corneal angiogenesis]

Recent advances in genetic engineering techniques have enabled large-scale manufacture of human epidermal growth factor (hEGF), making possible the clinical use of this particular agent in treating a variety of corneal epithelial disorders. In view of future application to humans, it has to be determined whether hEGF could induce neovascularization in the cornea upon topical instillation, since the angiogenic effect of mouse EGF on the cornea in vivo has been reported. For this, a sheet of slow-release form polymer (EVA) containing hEGF was surgically implanted into the rabbit corneal stroma in search for subsequent corneal neovascularization. EVA sheets contained one of the following agents: (1) 250ng hEGF, (2) 500ng hEGF, (3) 250ng bFGF (positive control), (4) vehicle alone (negative control). On 5 and 14 days after implantation, the corneas were excised, sectioned, and stained with hematoxylin and eosin for histological evaluation. Slit lamp examination revealed that marked neovascularization developed in the corneas when EVA sheets containing bFGF were implanted. A number of polymorphonuclear leukocytes were accumulated around the implants. However, neovascularization did not occur in the corneas when EVA sheets containing either concentrations of hEGF or vehicle alone were implanted. Only a few polymorphonuclear leukocytes infiltrated. This result indicates that as much as 500ng hEGF does not induce corneal neovascularization.