Healing Process of Tympanic Membrane Perforations Adjacent to the Auditory Ossicles in Animal Models

Abstract

We studied the healing process of tympanic membrane perforations in the external auditory canal in guinea pigs. The perforations were made apart from or adjacent to the malleus. The time for the closure of the tympanic membrane perforations was longest in perforations adjacent to the malleus, and in those cases the perforated part of the tympanic membrane regenerated and thickened around the malleus in the healing process. Moreover, immunohistological staining, using anti-BrdU antibody, revealed few stained cells in the intermediate layer except at the tip of the malleus. We consider that these findings were related to the delayed closure of the perforation.
Histological study of the regenerated tympanic membrane revealed that after closure of the perforation, a thinning of the epithelial layer was first observed, but cells in the layer later increased.