A model for quantitative measurement of sulfur mustard skin lesions in the rabbit ear

The search for treatment and protection against the vesicant and inflammatory skin lesions induced by sulfur mustard suffers from the lack of a good in vivo reproducible model. We applied sulfur mustard (25-500 microg/cm2) to the outer surface of the ears of 10 rabbits and measured the edema formation 12, 24 and 48 h post-application with a caliper especially designed for soft matter. There was a dose-dependent linear increase in edema magnitude in the range from 25 to 150 microg/cm2. Maximal edema was observed after 12 h. There was a 12% reduction in edema size 24 h after application and a further decrease after 48 h. Skin thickness, inflammatory cell infiltrate, necrosis and vesiculation were evaluated in biopsies taken after 24 h. We found the same dose-related increase both in skin thickness and in degree of blister formation. This simple dose-response in vivo model can be used for evaluation of the dermal inflammation induced by topical application of sulfur mustard. This model has the additional advantage of a built-in control, namely the untreated contralateral ear. Consequently, this model can serve as a useful tool for future screening of potential compounds for prevention and treatment of sulfur mustard-induced skin lesions.