2.4. Xylene-induced ear oedema of mice

Mice were segregated randomly into five groups (n = 6 per group): control group, xylene model group, and NK treated groups (3500, 7000, and 14000 FU/kg). Animals were orally administered with indicated doses of NK or ddH₂O for a week before xylene application. Xylene (30 μl) was smeared to the surface of the right ears for 30 min. The left ears were untreated and served as controls. Animals were sacrificed humanely under anesthesia, and two ear punches (8 mm, i.d.) were collected and weighed. The oedema was evaluated by comparing the increase in the weight of the right ear punch with the increase in the weight of the left ear punch.