Mitotic Activity of Tympanic Membrane and External Auditory Canal Skin in Normal Monogolian Gerbil

Abstract

BACKGROUND: Understanding the differentiation and migrating character of the tympanic membrane, external auditory canal as well as cholesteatoma pathogenesis needs knowledge about epithelial generation center. OBJECTIVE: We investigated the distribution of the epithelial generation center in the tympanic membrane and external auditory canal using 5-bromo-2-deoxyuridine(BrdU) immunohistochemistry. MATERIALS AND METHODS: BrdU was injected into peritoneum of 10 Mongolian gerbils and gerbil's temporal bones were obtained and serial section was done. Anti-BrdU antibody immunohistochemical stain was done. RESULTS: The labeling index was highest at posterosuperior quadrant of pars tensa, higher at malleus handle attached area and annulus region. On pars flaccida, labeling index was high at entire area. The labeling index of deep meatal skin was higher than that of lateral meatal skin, especially near annulus area. According to results, epithelial generation centers are thought to be on pars flaccida, posterosuperior quadrant of pars tensa, malleus handle attached area and annulus region. CONCLUSION: These findings are similar to those of human tympanic membrane and external auditory canal, and gerbils can be used as a animal model for study of normal human tymapnic membrane, external auditory canal and cholesteatomas.