Survival of bundleless hair cells and subsequent bundle replacement in the bullfrog's saccule

Authors

  • Jonathan E. Gale,

    Corresponding author
    1. Department of Otolaryngology, HNS and Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, Virginia 22908
    Current affiliation:
    1. Department of Physiology, University College London, Gower Street, London, WC1E 6BT, U.K
    • Department of Otolaryngology, HNS and Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, Virginia 22908
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  • Jason R. Meyers,

    1. Department of Otolaryngology, HNS and Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, Virginia 22908
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  • Ammasi Periasamy,

    1. Department of Biology, Keck Center for Cellular Imaging, University of Virginia, Charlottesville, Virginia 22906
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  • T. Corwin

    Corresponding author
    1. Department of Otolaryngology, HNS and Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, Virginia 22908
    • Department of Otolaryngology, HNS and Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, Virginia 22908
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Abstract

Our senses of hearing and balance depend upon hair cells, the sensory receptors of the inner ear. Millions of people suffer from hearing and balance deficits caused by damage to hair cells as a result of exposure to noise, aminoglycoside antibiotics, and antitumor drugs. In some species such damage can be reversed through the production of new cells. This proliferative response is limited in mammals but it has been hypothesized that damaged hair cells might survive and undergo intracellular repair. We examined the fate of bullfrog saccular hair cells after exposure to a low dose of the aminoglycoside antibiotic gentamicin to determine whether hair cells could survive such treatment and subsequently be repaired. In organ cultures of the bullfrog saccule a combination of time-lapse video microscopy, two-photon microscopy, electron microscopy, and immunocytochemistry showed that hair cells can lose their hair bundle and survive as bundleless cells for at least 1 week. Time-lapse and electron microscopy revealed stages in the separation of the bundle from the cell body. Scanning electron microscopy (SEM) of cultures fixed 2, 4, and 7 days after antibiotic treatment showed that numerous new hair bundles were produced between 4 and 7 days of culture. Further examination revealed hair cells with small repaired hair bundles alongside damaged remnants of larger surviving bundles. The results indicate that sensory hair cells can undergo intracellular self-repair in the absence of mitosis, offering new possibilities for functional hair cell recovery and an explanation for non-proliferative recovery. © 2002 Wiley Periodicals, Inc. J Neurobiol 50: 81–92, 2002; DOI 10.1002/neu.10002

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