Effect of topically applied 0.1% dexamethasone on endothelial healing and aqueous composition during the repair process of rabbit corneal alkali wounds

PURPOSE: The effects of topical dexamethasone on the endothelial healing and the change of aqueous compositions were investigated during the repair process of alkali-wounded rabbit cornea. METHODS: A central corneal alkali wound was produced by a 60 sec application of a 5.5 mm round filter paper soaked in 1N NaOH onto one eye of each rabbit. The eyes subsequently were treated topically with either 0.1% dexamethasone or a balanced salt solution (BSS) 4 times per day for 8 weeks. Endothelial wound morphometry was performed after alizarin red and trypan blue staining. The concentrations of ascorbic acid, glucose, and the ions, Na+, K+, Ca2+ and Mg2+, were measured in the aqueous humor. RESULTS: Endothelial healing in control (alkali-wounded but not treated with dexamethasone) corneas showed a biphasic pattern of healing: an initial short-term healing for the first week and then a late long-term healing following the secondary endothelial breakdown. Topical administration of 0.1% dexamethasone deterred endothelial healing during the early period and prevented the secondary endothelial breakdown. However, the total repair process of endothelium was accelerated by the dexamethasone-treatment. Among the various components of the aqueous humor examined, ascorbic acid seemed the most sensitive to change caused by the alkali injury and dexamethasone treatment. CONCLUSIONS: The present data indicate that dexamethasone may have a therapeutic potential in the management of endothelial healing after corneal alkali injury.