Epithelial wound closure in the rabbit cornea. A biphasic process.

The rapid and complete repair of the corneal epithelium following ocular surgery or trauma is essential for the maintenance of normal visual acuity. In this study the authors examined epithelial wound healing in the rabbit after cells were mechanically removed leaving the basal lamina intact. The decrease in wound area (mm2/hr) was neither linear nor amenable to simple kinetic analysis. However, analysis of the data in terms of the decrease in wound radius (mm/hr) revealed a biphasic process consisting of an initial latent phase with no epithelial movement (5.5 +/- .3 hr), followed by a linear healing phase. The rate of epithelial movement in the linear healing phase was 64 +/- 2 microns/hr. Neither the latent phase nor the rate of epithelial migration during the healing phase was affected by variations in initial wound size. Ultrastructural studies demonstrated that during the latent phase there was an increased desquamation of surface cells as well as cellular and subcellular reorganization of the basal cells. At the end of the latent phase, the leading edge of the wound was composed of a single cell layer. The onset of epithelial migration coincided with the first ultrastructural observation of typical ruffled membranes and filopodia. This work demonstrates that the analysis of the decrease in wound radius provides a straightforward and accurate means to assess the kinetics and therapeutic modulation of epithelial wound healing.