Cell Division and Maintenance of Epithelial Integrity in the Deafened Auditory Epithelium

Young Ho Kim and Yehoash Raphael

volume 6 | issue 5

1 March 2007
Pages: 612 - 619

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Quiescence is among the hallmarks of the sensory epithelium of the cochlea. When auditory sensory cells (hair cells) degenerate they are not replaced, and therefore hearing loss is permanent. Cochlear hair cells are susceptible to several types of lesions, including aminoglycoside antibiotics. The application of the aminoglycoside neomycin in the inner ear mimics cases of severe hair cell loss and leads to collapse of the cochlear epithelium. We now report that in mature guinea pig cochleae injected with neomycin, the remaining non-sensory cells undergo a robust proliferative response. p27Kip1, an inhibitor of cell cycle in the cochlea, was present in non-dividing cells and absent during mitosis. Dividing cells retained their tight junction complexes and maintained the structural confluence of the auditory epithelium during cell division. The plane of mitosis was invariably parallel to the luminal surface. These results indicate that the flat epithelium of the cochlea can down-regulate p27Kip1 and divide after a severe lesion and suggest that the cell divisions assist in maintaining the epithelial confluence throughout the cochlea. Presence of mitosis in the tissue presents therapeutic opportunities for gene transfer and stem cells therapies.

Authors

Young Ho Kim

Seoul National University College of Medicine, Seoul, South Korea

Yehoash Raphael

Kresge Hearing Research Institute, Ann Arbor, Michigan

We now provide open access to journal articles published online for one year or more. This article may be downloaded at the following link: