Hair-cell-membrane changes in the cochlea following noise

Details

• Personal Author:
  Bohne BA ; Harding GW ; Hsu K ; Schmitt N
• Description:
  The morphological correlates of temporary threshold shift (TTS) remain controversial. Mulroy et al ('98) provided indirect evidence that alligator lizards with noise-induced TTS have microlesions in hair-cell plasma membranes. To test this hypothesis directly, chinchillas were exposed for 24 hrs to a 4-kHz OBN at 92 dB SPL. ABR & DPOAE testing were carried out pre- & post-exposure. Three hrs post-exposure, 3 chinchillas had EP measured & carbon particles injected into the endolymphatic space before fixation. Two chinchillas recovered for 1 or 2 wks before EP measurement, carbon injection & cochlear fixation. Two controls underwent EP measurement (74 & 89 mV), carbon injection & cochlear fixation. Cochleas were embedded in plastic, dissected as flat preparations & missing cells counted. Cytocochleograms were prepared with functional data overlaid according to the chinchilla frequencyplace map. Thin sections of the OC were cut in the region of maximum threshold shift (TS) for TEM. Immediately post-exposure, all animals had an ABR TS of 20-60 dB over a frequency range of 1-16 kHz & a DPOAE level shift (LS) of 10-50 dB over 2-16 kHz; EP was 21, 49 & 79 mV in the three 0-d-recovery animals. Most hair cells were present & had normal shapes by phase contrast microscopy; by TEM, OHC stereocilia were slightly disarrayed but the plasma membranes were intact. The 1-wk-recovery animal had an ABR TS of 10-20 dB for 1-16 kHz, a DPOAE LS of 12-30 dB for 3-12 kHz & an EP of 83 mV. The 2-wk-recovery animal had an ABR TS of 10-20 dB for 3-6 kHz, a DPOAE LS of 12-23 dB for 3-12 kHz & an EP of 80 mV. In the 1-wk-recovery animal, one region of the OC contained about 20% degenerating OHCs. By TEM, the apical membranes of some degenerating hair cells contained microlesions. We conclude that hair cells do not develop microlesions in noise-exposed mammalian cochleas unless the cells are degenerating. [Description provided by NIOSH]
• Subjects:
  Animals Hearing Hearing Loss Hearing Loss, Noise-Induced Laboratories Noise Occupational Health Safety
• Keywords:
  Animal-studies Cell-damage Cellular-reactions Exposure-levels Hearing-disorders Hearing-loss Laboratory-animals Noise-exposure Noise-induced-hearing-loss
• ISSN:
  0742-3152
• Publisher:
  Association for Research in Otolaryngology
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  Florida ; Missouri ; New Jersey ; OSHA Region 2 ; OSHA Region 4 ; OSHA Region 7
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  27
• NIOSHTIC Number:
  nn:20041605
• Citation:
  Abstr Midwinter Res Meet Assoc Res Otolaryngol 2004 Feb; 27:132
• Editor(s):
  Santi PA
• Federal Fiscal Year:
  2004
• NORA Priority Area:
  Disease and Injury: Hearing Loss
• Performing Organization:
  Washington University, St. Louis
• Peer Reviewed:
  False
• Start Date:
  20000401
• Source Full Name:
  Abstracts of the 27th Midwinter Research Meeting of the Association for Research in Otolaryngology, Febuary 21-26, 2004, Daytona Beach, Florida
• End Date:
  20130914
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:c69835f6179ecbb48ebc5048cc2412fae5dde8a1b9dcbf2e73a811e98c056fd656bacff09a2bfd00f5a87b280ad589f60add1b5eeddad6101ef8142d75f7c877
• Download URL:
  https://stacks.cdc.gov/view/cdc/194119/cdc_194119_DS1.pdf
• File Type:
  [PDF - 90.75 KB ]