Immunohistochemical localization of proliferating cells and epidermal growth factor receptors in mouse olfactory epithelium.

We investigated age-related changes in proliferating cells and epidermal growth factor receptors (EGFRs) in mouse olfactory epithelium using an immunohistochemical method with the antiproliferating cell nuclear antigen (PCNA) antibody and the antihuman EGFRs antibody. Many PCNA-positive cells occurred in the surface and basal layers of the olfactory epithelium in the embryonal and neonatal mice. However, only some PCNA-positive cells occurred in the basal layer of adult mice, and only a few presented in the basal layer of aged mice. EGFRs were observed in all layers of the olfactory epithelium at the embryonal and neonatal stages, but were not identified in the olfactory epithelium at the adult or aged stages. We believe that a decrease in EGFRs in the olfactory epithelium induces the inhibition of cell proliferation, with the resultant atrophy of the olfactory epithelium.