Oxazolone-Induced Ear Edema in Mice [103]. The
oxazolone-induced ear edema in mice is a model of delayed
contact hypersensitivity that permits the quantitative evaluation
of the topical and systemic anti-inflammatory activity
of a compound following topical administration. Procedure.
Mice are divided into various groups (n = 6), and a fresh
2% solution of oxazolone (4-ethoxymethylene-2-phenyl-
2-oxazolin-5-one) in acetone is prepared. The mice are
sensitized by application of halothane anesthesia (0.1 mL on
the shaved abdominal skin or 0.01 mL the inside of both
ears). The mice were challenged with 0.01 mL 2% oxazolone
solution 8 days later, under anesthesia, inside the right ear
(control) or 0.01 mL of oxazolone solution in which the
test compound or standard drug is dissolved. Groups of 10
to 15 animals are treated with the irritant alone or with
the solution of the test compound. The left ear remains
untreated. The maximum inflammation occurs 24 h later,
when the animals are sacrificed under anesthesia and a disc
of 8 mm diameter is punched from both sides. The discs are
immediately weighed on a balance and the weight difference
is an indicator of the inflammatory edema.