Effect of Hyaluronic Acid on Corneal Re-epithelization in Rats following Excimer Laser Keratectomy

Kim, Ki Bong; Kim, Jae Ho

Abstract

The effect of hyaluronic acid(HA) on corneal reepithelization following excimer laser keraectomy was evaluated in rats. An argon fluoride excimer laser(193nm) was used to perform laser keratectomy in each eye of 44 rats (4mm in diameter and 38micrometer in depth). The animals were divided into two guoups: the control group(dropping with PBS) and the HA treated group (dropping with 10mg/ml HA). The healing rate of the epithelial defectarea as well as morphologic changes were observed and the healing response of the cornea was analyzed immunohistochemically to determine the dirsribution of fibronectin. The results were as follows: 1. The reduction of epithelial defect area after 15 hours following laser keratectomy was significantly accelerated in HA treated group compared with the control group(P<0.005). The mean epithelial healing rate was 0.38+/-0.05mm2/hr in the HA treated group and 0.32+/-0.05mm2/hr in the control group. 2. Histologically, remarkable epithelial thickening and less polymorphonuclear leukocyte infiltration under leading epithelium in the HA treated group were observed, which were limited in anterior stroma. 3. Under the transmission electrom microscope, after 72 hours, the intercellular spaces of wing cell layer were bridged by desmosoes more tightly, and remarkable hemidesmosomes were shown in Ha treated group compared with the control group. 4. Fibronectin immunoreactivity observed was under the leading epithelium by using immunohistochemistry at 15 hours following keratectomy in both groups. The results indicate that hyaluronic acid stimulates epithelial wound healing following excimer laser keratectomy by enhancing cell migration and promoting the tight ntercellular junction. The expression of fibronectin was not influenced by HA.