Abstract
Purpose :
Sulfur/Nitrogen Mustard are vesicants that can induce signifcant toxic effects on the ocular surface. Following the acute injury, a subset of patients go on to develop chronic and/or delated onset disease known as mustard gas keratopathy (MGK). The purpose of these studies is to develop murine models to study the pathophysiologic mechanisms of the chronic/delayed-onset MGK.
Methods :
All animal experiments were conducted in compliance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. The protocol was approved by the ACUC at University of Illinois at Chicago (UIC) and the IBC Biosafety Committee. 2-3 month old C57BL/6J mice were anesthetized then 5ul of Nitrogen Mustard (NM) ranging in concentration from 0.5mM to 60mM was applied to the central cornea for 5 min then rinsed with PBS. The corneas were examined by slit lamp and fluorescein staining up to 4 months. A 2mm debridement wound at 4 monthswas used to "challenge" the eyes that had mostly recovered from the NM injury.
Results :
There was dose-dependent corneal toxicity across the range of NM concentrations. Concentrations of 5mM or below resulted in minimal to no corneal disease. Injury with 20mM NM resulted in some acute changes manifested by corneal edema and epithelial staining, which typically resolved by 1 month. Injury with 40nM of NM resulted in more severe acute changes which progressed to corneal scarring and neovascularization at 1 month. Concentrations of 60mM and higher resulted in significant corneal damage and secondary infections. At 4 months, all of the corneas injured with 40mM NM had persistent scarring while the 20mM injured corneas were mostly normal. Following the 2mm epithelial decridement "challenge" at 4 months, the corneas previoulsy injured with 20mM NM developed significant corneal disease with delayed healing, scarring and neovascularizarion.
Conclusions :
These studies provide potential models for studying MGK. Higher concentration of NM (40mM for 5 min) results in more of chronic disease with progressive scarring and neovascularizaion while a lower concentrations (20mM for 5 min) typically has minimal to residual corneal disease aftre a few months and may be more suitable for studying delayed-onset disease. A delayed debridement challenge of grossly normal corneas consistently resulted in severe corneal scarring and inflammation which could be used to simulate/induce a "delayed-onset" disease.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.