Histology of and quantitative assays for oxazolone-induced allergic contact dermatitis in mice

Oxazolone-induced allergic contact dermatitis in mice has been used as an in vivo model for identifying potential anti-inflammatory and immune-modulating drugs. Studies were conducted with this model to detail the histokinetics of the inflammatory response and to examine the adequacy of three assays for measuring the intensity of the inflammatory response when compared to histologic findings. CD-1 mice were sensitized with oxazolone on the flank and challenged on the dorsum of the ear pinna. The inflammatory response was quantitated by measuring the change in pinna weight and thickness and presence of 125I-2-deoxyuridine (125IUDR)-labeled cells. Cellular infiltrate was mixed with general predominance of mononuclear cells over neutrophils. Correlation with the histologic data suggests that both the ear weight and thickness assays are suitable primary screening assays, since both provided a sensitive, accurate and objective measure of the inflammatory response and its suppression by dexamethasone. The 125IUDR assay worked well in untreated mice but was unsatisfactory in mice treated topically or systemically with dexamethasone.