Noise-induced focal lesions in the Organ of Corti: distribution and cell-death pathways

Details

• Personal Author:
  Bohne BA ; Harding GW
• Description:
  Studies have been conducted to identify what death pathways OHCs follow after moderate-severe noise exposures. Identified pathways include oncosis/necrosis, apoptosis & a non-apoptotic, non-oncotic pathway. IHCs, pillar & Deiters cells are also destroyed by noise. In order to develop treatment strategies that will minimize noise-induced hearing loss, it is important to identify death pathways in all cell types in the organ of Corti (OC). Eighteen chinchillas were exposed for 1 h to a 4-kHz OBN at 108 dB SPL. Recovery times were < 1 d to 30 d post-exposure. At termination, animals were anesthetized; their cochleae surgically exposed & fixed in-vivo with 1% buffered OsO4. The intact cochleae were dehydrated, embedded in plastic & dissected into flat preparations. For each ear, OC length was measured & losses of cells were quantified throughout the OC. Focal hair-cell lesions were identified [= 50% loss of OHCs, IHCs or both (i.e., combined) over at least 0.03 mm] and death pathways in dying cells determined. All but one cochlea had one or more focal hair-cell lesions. In different cochleae, some lesions covered a narrow portion of the OC & were close to the 4-kHz OBN location, while some lesions were spread over approximately 50% of the OC. In cochleae with two or more lesions, variable-length areas of reduced damage separated the lesions. Twice as many OHC lesions as combined & IHC lesions were identified. OHC & combined lesions were greater in length than IHC lesions & usually included missing pillars & Deiters cells. IHC lesions rarely involved other cell types. This suggests that IHC lesions are generated by a different mechanism than OHC & combined lesions. Within the OHC & combined focal lesions, dying hair cells were identified that were following the oncotic, apoptotic & non-apoptotic, non-oncotic death pathways. The identification of death pathways followed by IHCs in IHC focal lesions & by supporting cells in OHC & combined focal lesions is in progress. [Description provided by NIOSH]
• Subjects:
  Animals Hearing Hearing Loss Hearing Loss, Noise-Induced Laboratories Noise Occupational Health Safety
• Keywords:
  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:
  Maryland ; Missouri ; OSHA Region 3 ; OSHA Region 7
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  47
• Volume:
  32
• NIOSHTIC Number:
  nn:20041557
• Citation:
  Abstr Midwinter Res Meet Assoc Res Otolaryngol 2009 Feb; 32:47
• Contact Point Address:
  Barbara A. Bohne, Ph.D., Washington University School of Medicine, Dept. of Otolaryngology, Box 8115, 660 South Euclid A venue, St. Louis, MO 63110
• Email:
  bohneb@ent.wustl.edu
• Editor(s):
  Santi PA
• Federal Fiscal Year:
  2009
• NORA Priority Area:
  Manufacturing ; Wholesale and Retail Trade
• Performing Organization:
  Washington University, St. Louis
• Peer Reviewed:
  False
• Start Date:
  20000401
• Source Full Name:
  Abstracts of the 32nd Midwinter Research Meeting of the Association for Research in Otolaryngology, Febuary 14-19, 2009, Baltimore, Maryland
• End Date:
  20130914
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:caa2eb4c1da67014b80a55a43388fa0d872bf44754da7225de02adca7b0de1657ea6c7a13aa0f07210da2565c9b0473d747fa05cce4d3262efedbcc7c6608e26
• Download URL:
  https://stacks.cdc.gov/view/cdc/194092/cdc_194092_DS1.pdf
• File Type:
  [PDF - 361.05 KB ]