2.4 Histological and immunochemistry analysis
The ear and dorsal skin were fixed with 4% paraformaldehyde, embedded in paraffin and cut into 5μm thick sections. Samples were then treated with Hematoxylin and Eosin (H&E) to detect epidermal thickening and inflammatory infiltration. Toluidine blue (TB) was used to evaluate the infiltration of mast cells. The number of mast cells in five randomly targeted sites was counted using a light microscope (Nikon Eclipse Ni, Tokyo, Japan) with ×200 magnification.