Balance dysfunction resulting from acute inner ear energy failure is caused primarily by vestibular hair cell damage

Kunio Mizutari, Masato Fujioka, Susumu Nakagawa, Masato Fujii, Kaoru Ogawa, Tatsuo Matsunaga

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

Inner ear energy failure is associated with disorders such as inner ear ischemia. Recently, we used the mitochondrial toxin 3-nitropropionic acid (3-NP) to establish an animal model of inner ear energy failure that presents with auditory dysfunction. Here we investigated the mechanisms underlying balance disorders in the 3-NP animal model. Spontaneous nystagmus peaked 6 hr after treatment with either 300 mM or 500 mM 3-NP. The nystagmus attenuated gradually and disappeared 3 days after 3-NP treatment. A caloric test using ice water was performed to evaluate residual vestibular function 7 days after 3-NP treatment. The response to caloric stimulation was reduced to ∼40% of the response of the untreated ear following 300 mM 3-NP and was undetectable following 500 mM 3-NP. Structural changes in the peripheral vestibular organs were analyzed by light and electron microscopy. Severe loss of stereocilia was observed following 500 mM 3-NP, whereas disorganized and mildly reduced stereocilia were observed following 300 mM 3-NP. There was severe loss and degeneration of vestibular hair cells following 500 mM 3-NP but only slight loss and degeneration of hair cells following 300 mM 3-NP. These results indicate that acute inner ear energy failure causes balance dysfunction mainly by damaging hair cells in the vestibule, which is distinct from the mechanism underlying auditory disorders.

Original languageEnglish
Pages (from-to)1262-1272
Number of pages11
JournalJournal of neuroscience research
Volume88
Issue number6
DOIs
Publication statusPublished - 2010 May 1

Keywords

  • Balance
  • Energy
  • Hair cell
  • Hair cells
  • Vestibular

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience

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