The Distribution of CD44 in Wound Healing of Rabbit Alkali Burn

ABSTRACT

An alkali burn of the cornea severely damages not only the epithelium but also the underlying keratocytes and endothelium, the extracellular matrix is thought to play an important role in burn wound healing of the cornea. The glycoprotein CD44 of extracellular matrix has been implicated in biological cell behavior, including lymphocyte binding to endothelial venules, embryonic development cell migration, cell differentiation, and tumor metastasis. The purpose of this study is to investigate the presence and distribution of CD44 in wound healing using immunohistochemical staining method after alkali burning of rabbit cornea. 2 hour after burn, there was no immunodeposit for CD44 at keratocytes and endothelial cells at denuded epithelial burn area. 4 hours postburn, the epithelial cell gradually migrated over the burn area from the peripheral unburn area and immunodepositive staining of the keratocytes was observed at the margin of burn site. 24 hours postburn, immunopositive reaction for CD44 at adjacent alkali burn area was more strongly labeled, but the peripheral epithelial response of unburn area was faintly labeled by them. 48 hours postburn, immunopositive reaction gradually shifted from the border portion of alkali burn to the center portion of burn site. On days 7, the epithelium was completely reepithelized over the burn area and 3 weeks postburn, immunostaining were demonstrated the entire layer of burn site. The recovering time of the nornal immunostaing for CD44 of the rabbit cornea from the alkali burn was taken about 7 weeks. Our results suggest that the CD44 protein can be seen in proliferating in the epithelial cells, the keratocytes end endothelial cells, and is thought to play an important role in wound healing of the alkali burn cornea.