Histology staining
The epithelial specimens underwent standard histological techniques. The samples were dehydrated using a series of ethanol concentrations and then cleared with xylene. Following infiltration and embedding in paraffin wax (melting point 56-58℃), they were sectioned using a rotary microtome (PR-50; Yamato Kohki Industrial Co., Ltd, Saitama, Japan) into slices measuring 4-6 μm. These sections were spread out on warm water, carefully transferred onto glass slides, and subsequently dried in an incubator at 60℃ for 30 minutes. During the staining process, they were sequentially immersed in deparaffinization solution, hydration medium, and stain solution. Following mounting, the epithelial samples were examined and photographed using a digital microscope (VHX-7000; Keyence, Osaka, Japan). We evaluated whether these epithelial tissues qualified as olfactory epithelium based on the criteria proposed by Farnkopf et al. (2022): epithelium constructed of basal cells, supporting cells, and olfactory sensory neurons; the presence of Bowman’s glands; the absence of goblet cells; and the distance between the apical surface and the nuclei of the supporting cells.