The mouse ear
edema model is recognized for its usefulness in studying skin responses and damage following exposure to chemical irritants, and for evaluating pharmacological agents against chemically induced skin injury. We recently modified the mouse ear
edema model for use with
sulfur mustard (HD) and used this model to study the protective effect of 33 topically applied compounds comprising five
pharmaceutical strategies (
anti-inflammatories,
protease inhibitors, scavengers/
chelators,
poly(ADP-ribose) polymerase (
PARP) inhibitors,
calcium modulators/
chelators) against HD-induced dermatotoxicity. Pharmacological modulation of HD injury in mouse ears was established by a reduction in
edema or histopathology (epidermal
necrosis and epidermal-dermal separation) at 24 h following topical liquid HD exposure. Ten of the 33 compounds administered as single topical pretreatments up to 2 h prior to HD challenge produced significant reductions in
edema. Five of these ten also produced significant reductions in histological endpoints. Three candidates (
olvanil,
indomethacin,
hydrocortisone) showing protection at 24 h were evaluated further for 'extended protection' at 48 and 72 h after HD challenge and showed significant modulation of
edema at 48 h but not at 72 h.
Olvanil also showed significant reductions in histology at 48 and 72 h.
Olvanil and
indomethacin were shown to reduce significantly the
edema at 24 h post-exposure when administered topically 10 min after HD challenge, with
olvanil additionally protecting against epidermal
necrosis. These results demonstrate prophylactic and treatment effects of pharmacological agents against HD-induced skin injury in an in vivo model and support the continued use of the mouse ear
vesicant model (MEVM) for evaluating medical countermeasures against HD.