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Modified Experimental Conditions for Noise-Induced Hearing Loss in Mice and Assessment of Hearing Function and Outer Hair Cell Damage
07:13

Modified Experimental Conditions for Noise-Induced Hearing Loss in Mice and Assessment of Hearing Function and Outer Hair Cell Damage

Published on: February 10, 2023

Calcineurin activation contributes to noise-induced hearing loss

Shujiro B Minami1, Daisuke Yamashita, Jochen Schacht

  • 1Kresge Hearing Research Institute, University of Michigan, 1301 E. Ann Street, Ann Arbor, MI 48109-0506, USA. josef@umich.edu

Journal of Neuroscience Research
|September 25, 2004
PubMed

Insights

Intense noise exposure activates calcineurin, a protein linked to auditory hair cell death. Inhibiting calcineurin protected guinea pigs from noise-induced hearing loss and hair cell damage.

Area of Science:

  • Oto-neurology
  • Cell Biology
  • Pharmacology

Background:

  • Acoustic overstimulation elevates intracellular calcium (Ca2+) in auditory hair cells.
  • Calcineurin, regulated by Ca2+ and calmodulin, is implicated in cell death pathways.

Purpose of the Study:

  • To investigate the role of calcineurin in auditory hair cell death following intense noise exposure in guinea pigs.
  • To evaluate the therapeutic potential of calcineurin inhibitors against noise-induced hearing loss.

Main Methods:

  • Guinea pigs were exposed to intense noise (4-kHz octave band, 120 dB, 5 hr).
  • Calcineurin immunoreactivity in hair cells was assessed post-exposure using immunohistochemistry.
  • Propidium iodide (PI) staining evaluated cell membrane integrity in calcineurin-immunopositive cells.
  • The effects of calcineurin inhibitors (FK506, cyclosporin A) on auditory brain stem response (ABR) thresholds and hair cell survival were measured.

Main Results:

  • Noise exposure induced calcineurin immunoreactivity in hair cells, peaking immediately after exposure and decreasing over 7 days.
  • Calcineurin-immunopositive cells showed PI uptake, indicating cell membrane breakdown and incipient cell death.
  • Local application of calcineurin inhibitors significantly reduced ABR threshold shifts and hair cell death.
  • Hair cell loss correlated inversely with calcineurin immunoreactivity levels over time.

Conclusions:

  • Calcineurin plays a significant role in mediating auditory hair cell death after acoustic trauma.
  • Calcineurin inhibitors demonstrate potential as a therapeutic strategy to protect the organ of Corti from noise-induced damage.
  • Targeting calcineurin may offer long-term protection against noise trauma, preserving hair cell integrity and auditory function.

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