Abstract
Purpose: :
Alkali injury of the eye results in epithelial defects of the cornea persisting until vascularization supervenes. The purpose of our experiments was to determine whether the presence of any normal stroma in an alkali injured eye has any influence on epithelial wound healing. For this we performed in vivo lamellar keratectomy studies in rabbits.
Methods: :
Using a Lamellar Keratoplasty technique the anterior one-half of the stroma of the alkali injured cornea was switched with the anterior one-half of the stroma of an abraded cornea and vise versa. The resulting lamellar corneal transplant was therefore sutured into the opposite bed. The eyes were examined daily for 5 days with particular attention to epithelial growth using slit lamp methods. The tissues were subsequently analyzed for fibronectin and apoptosis by immunohistochemistry.Clinical
Results: :
Abraded Cornea Donor into Alkali Injured Cornea: The epithelial defect reduced from 11.0mm to a small oblong shaped defect within 48 hours; completely disappearing by 72 hours. At 120 hours a small incomplete epithelial defect was noted. Opacification of the residual stroma was severe at all periods from 24 hours to the end time point of 120 hours.Abraded Cornea Donor into Normal Cornea. The epithelial defect reduced from 11.0 mm to a small circular defect within 72 hrs and completely gone by 96 hrs. There was no significant change in corneal opacity from 24 hrs to the end time point of 120 hrs. Corneal edema was noted to be moderate at all examinations.Alkali Cornea Donor into Normal Cornea. The epithelial defect reduced from 11.0 mm to a small triangular shaped defect within 48 hrs; completely gone by 72 hrs. There was no significant change in corneal opacity from 24 hours to the end time point of 120 hrs. Opacification was noted as moderate at all examinations. In all cases there was a decrease in TUNEL positive cells and an initial increase in fibronectin expression, decreasing by 120 hours, when the re-epithelialization was complete.
Conclusions: :
Our experiments showed that the presence of any normal stroma in the cornea in an alkali injured eye facilitated corneal epithelialization. The presence of normal stroma in an alkali injured eye appears to provide critical component(s) to the epithelial wound healing process. We believe that normal stroma provides a signaling mechanism enhancing corneal epithelialization, after alkali injury.
Keywords: cornea: stroma and keratocytes • cornea: epithelium • apoptosis/cell death