Late-phase recovery in the cochlear lateral wall following severe degeneration by acute energy failure

Kunio Mizutari, Susumu Nakagawa, Hideki Mutai, Masato Fujii, Kaoru Ogawa, Tatsuo Matsunaga

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

We previously reported a model of acute cochlear energy failure using a mitochondrial toxin, 3-nitropropionic acid (3-NP), to study mechanisms of inner ear disorders such as inner ear ischemia. In this model, the main cause of hearing loss is apoptosis of fibrocytes in the cochlear lateral wall. Here, we analyzed the time course of structural and hearing level changes in the cochlea from the acute phase to the chronic phase up to 2 months after surgery. Hearing levels as determined by auditory brainstem response (ABR) thresholds exceeded the maximum acoustic output (> 87 dBSPL) of the system at all frequencies 1 day after 3-NP treatment. Histology showed nearly complete loss of fibrocytes 2 weeks after 3-NP treatment. However, after 2 months, ABR showed significant recovery at low frequency (8 kHz) in four of five rats treated with 3-NP. ABR thresholds at 20 kHz occasionally showed some recovery. At 40 kHz, recovery of ABR thresholds was not observed. Histology of 3-NP-treated rats revealed partial recovery of the lateral wall and the regenerated fibrocytes in the spiral ligament expressed Na/K-ATPase in the cochlear basal turn 2 months after 3-NP treatment. These results indicate that ABR recovery is caused by regeneration of the cochlear lateral wall. Our findings demonstrate the recoverable capacity of the cochlear lateral wall that leads to functional recovery after severe damage.

Original languageEnglish
Pages (from-to)1-11
Number of pages11
JournalBrain Research
Volume1419
DOIs
Publication statusPublished - 2011 Oct 24

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Cochlea
Brain Stem Auditory Evoked Potentials
Inner Ear
Hearing
Histology
Spiral Ligament of Cochlea
Hearing Loss
Acoustics
3-nitropropionic acid
Regeneration
Therapeutics
Ischemia
Apoptosis

Keywords

  • 3-nitropropionic acid (3-NP)
  • Cochlear lateral wall
  • Fibrocyte
  • Recovery
  • Spiral ganglion

ASJC Scopus subject areas

  • Neuroscience(all)
  • Clinical Neurology
  • Developmental Biology
  • Molecular Biology

Cite this

Late-phase recovery in the cochlear lateral wall following severe degeneration by acute energy failure. / Mizutari, Kunio; Nakagawa, Susumu; Mutai, Hideki; Fujii, Masato; Ogawa, Kaoru; Matsunaga, Tatsuo.

In: Brain Research, Vol. 1419, 24.10.2011, p. 1-11.

Research output: Contribution to journalArticle

Mizutari, Kunio ; Nakagawa, Susumu ; Mutai, Hideki ; Fujii, Masato ; Ogawa, Kaoru ; Matsunaga, Tatsuo. / Late-phase recovery in the cochlear lateral wall following severe degeneration by acute energy failure. In: Brain Research. 2011 ; Vol. 1419. pp. 1-11.
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