2.8. Passive Cutaneous Anaphylaxis (PCA) in Mice

At day 1, anti-DNP-IgE (4 μg/mL) antibody was subcutaneously injected into the ears of mice. At day 2, IgE-sensitized mice were administered oral SIE (250 or 500 mg/kg) or dexamethasone (10 mg/kg). One hour later, DNP-HSA (300 μg/mL) containing 1% Evans blue was injected into the tail veins. One hour later, the mice were sacrificed using CO₂ and tissues from the treated ears were obtained. The Evans blue dye was removed by the ear tissue, which were then incubated with 0.4 mL formamide at 63°C for 16 hr. Absorbance at 620 nm wavelength was measured using a microplate reader.