Disappearance of desmosomal components in rat corneal epithelium during wound healing

Purpose: Epithelial migration is essential for healing of the ablated corne al epithelium. To reveal the mechanism which enables the corneal epithelial cells to dissociate during migration, we investigated the immunolocalizati on of the components of the desmosome, which is the main constituent of the intercellular junction attaching the intermediate filaments to the cell su rface, desmoplakin 1, desmoglein and plakoglobin, in the corneal epithelium during wound healing in rats. Methods: Under general anesthesia with ether inhalation, Wistar rats (n = 48) underwent removal of the central corneal epithelium of one eye with a small trephine and a sealpel. After various in tervals of healing (5 min; 1,3, 6, 9, 12, 24, 48 h; 1 and 2 weeks), the ani mals were killed and the affected eye was excised. Cryosections of each ant erior segment of the eye were fixed with cold acetone and treated with prim ary antibodies against desmoplakin 1, desmoglein and plakoglobin. Immunoloc alization of these substances was visualized by the peroxidase-diaminobenzi dine reaction. Results: A marked immunoreactivity for these desomosome comp onents was detected at the intercellular junction in the normal corneal and conjunctival epithelium. At 6-24 h after epithelial ablation, a weak immun oreactivity for desmoplakin 1 and plakoglobin was observed in the migrating epithelium. At 48 h after epithelial ablation, a marked immunoreactivity f or these desmosome components was seen again. At 6-48 h after epithelial ab lation, a weak immunoreactivity for desmoglein was observed in the migratin g epithelium. At 1 week after epithelial ablation, a marked immunoreactivit y for this desmosome component reappeared. The regenerated epithelium gradu ally exhibited normal immunolocalization of the proteins. Conclusions: The desmosome components were considered to be degraded or destroyed prior to e pithelial migration and reconstructed during healing of the squamous epithe lium. Copyright (C) 2001 S. Karger AG,Basel.