Beneficial effects of topical anti-inflammatory drugs against sulfur mustard-induced ocular lesions in rabbits

Ocular injuries following sulfur mustard (HD) exposure are characterized by an inflammatory response, observed as eyelid swelling, conjunctivitis, cor neal oedema and cellular infiltration starting 1-4 h after exposure, depend ing on dose. These effects heal partially during the first 1-2 weeks after exposure, with the later appearance of neovascularization, recurrent erosio ns and recurrent oedema of the cornea (delayed response). We have shown pre viously that topically applied steroid treatment, administered after HD exp osure, attenuated the extent of neovascularization, one of the characterist ics of delayed ocular pathology in rabbits. The present study was designed to characterize further the initial inflamma tory response and to elucidate the role of anti-inflammatory (AI) drugs as a potential therapy. Rabbit eyes were exposed to HD vapour (390 mug l(-1) f or 2 min) acid were treated with a topical commercial ophthalmic solution o f dexamethasone or diclofenac, starting Ih post-exposure (four times a day) . Inflammation was evaluated by clinical observations, biochemical analysis of aqueous humour and by histology. Sulfur mustard exposure initiated typical clinical ocular symptoms within 4 -6h after exposure. Biochemical analysis of aqueous humour showed that prot ein content and prostaglandin E (PGE) increased significantly at 6 h and we re still high 48 h after HD exposure. Light microscopy evaluation revealed severe damage to the cornea, characterized by epithelial denudation, oedema and cellular infiltration (mostly eosinophiles) in the stroma, Both treatm ents were effective in alleviating the clinical symptoms and in preventing the HD-induced increase in protein and PGE in the anterior chamber, as well as the cellular infiltration, in the corneal stroma, However, the AI treat ments had no therapeutic effect on corneal erosions, and a short delay in e pithelial regeneration was noted. It is concluded that AI drugs are potential candidates for the treatment of ocular lesions following HD exposure. Copyright (C) 2000 John Wiley gi Son s, Ltd.