Antimetabolite interactions with epidermal growth factor.

Antimetabolites such as 5-fluorouracil and mitomycin C are known to delay wound healing. Epidermal growth factor (EGF) has been shown to accelerate corneal epithelial wound healing. This study was designed to investigate the effects of EGF on corneal epithelial healing that has been modified by antimetabolite treatment. New Zealand White rabbits were pretreated with either saline (controls) or 5-fluorouracil (5FU) injected subconjunctivally, or mitomycin C (MMC) applied topically. Circular anterior stromal wounds were created, followed by a 6-hour perfusion of normal saline or 50 micrograms/ml of EGF. Subconjunctival saline or 5FU, or topical MMC treatments were continued after wounding for a total of 6 days. Corneas were photographed and quantitative morphometry of the wound site was performed. Compared with saline controls, MMC significantly delayed wound healing (P < 0.05) whereas 5FU did not (P > 0.05). Compared with 5FU, MMC significantly delayed wound healing with either normal saline or EGF perfusion (P < 0.05). In the presence of either 5FU or MMC, EGF perfusion had no significant effect on the corneal wound-healing rate (P > 0.05). Corneal wound healing is not affected by subconjunctivally injected 5FU while it is delayed by topically applied MMC. EGF treatment does not overcome the inhibitory effects of MMC. EGF therapy may not be useful in the treatment of complications related to antimetabolite therapy.