4.15. Croton Oil-Induced Ear Edema

The procedure was adapted from Paiva et al. [7]. Balb/c mice (n = 6 animals/group) were weighed and distributed into the experimental groups (Table 2). The mice received croton oil topical application (20 µL/ear, 5% in acetone 70%) on the right ear one hour after each treatment, while the left ear was treated with 70% acetone (20 µL/ear). After four hours of croton oil application, the animals were euthanized and the ear edema was determined by weight difference between the left and right ears. Immediately after weighing, the ear fragments were stored in liquid nitrogen for the measurement of myeloperoxidase. A satellite group (without treatment) was also used for the evaluation of myeloperoxidase.

Group distribution in the croton oil induced ear edema assay in mice.

^an = 6 Balb/c mice/groups; ^b Negative control (70% acetone on topical administration and PBS with 5% Tween 80 by oral administration; ^c Positive control and ^d alkaloid enriched fraction of B. caudata.