CONTINUOUS EPIDERMAL GROWTH-FACTOR DELIVERY IN CORNEAL EPITHELIAL WOUND-HEALING

Purpose. To investigate the effects of a single prolonged exposure to recombinant epidermal growth factor on the healing of anterior keratot omy wounds in New Zealand white rabbits. Methods. After wounding, eyes were perfused for 1, 2, 4, and 8 hours with either epidermal growth f actor solution at a concentration of 50 mug/ml or balanced saline solu tion using a Morgan therapeutic lens (Mortan Inc, Missoula MT) and a s yringe pump. Furthermore, concentration response was evaluated by perf using with epidermal growth factor solutions at concentrations of 5, 5 0, 1 00 and 500 mug/ml for 4 hours. Wound healing rates were determine d by quantitative morphometry of the wound area. The ratio of healing rates of eyes perfused with epidermal growth factor and control eyes p rovided a measure of the effect of epidermal growth factor on wound he aling, and was defined as the epidermal growth factor enhancement fact or. Results. The enhancement factor was found to be 1.04 +/- 0.08, 1.1 7 +/- 0.07, 1.43 +/- 0.09, and 1.59 +/- 0.07 for perfusion times of 1, 2, 4, and 8 hours, respectively. The concentration response enhanceme nt factors were 0.99 +/- 0.08, 1.43 +/- 0.09, 1.21 +/- 0.09, and 0.95 +/- 0.07 for the 5, 50, 100, and 500 mug/ml 4-hour perfusions, respect ively. Conclusion. The results indicated that continuous epidermal gro wth factor exposures of as few as 2 hours produced a significant incre ase in healing rates (P < 0.05); increasing the time of exposure furth er increases the rate of wound healing. Results from the concentration response experiments showed that the optimum epidermal growth factor concentration for enhancing epithelial wound healing is approximately 50 mug/ml.