Free Radical Generation in the Cochlea During Combined Exposure to Noise and Carbon Monoxide: An Electrophysiological and an EPR Study

Details

• Personal Author:
  Fechter LD ; Moore DR ; Rao DB ; Reinke LA
• Description:
  Ototoxicity following combined exposure to noise and carbon monoxide (CO) is known to result in more severe permanent threshold shifts than exposure to noise alone. We have previously demonstrated that such potentiation of noise-induced auditory impairment by CO can be prevented by the administration of a nitrone spin-trapping agent. Although such protection implicates injury via free radical pathways, drug-induced protection does not provide direct evidence for the presence of free radicals in the cochlea. The objective of this study was to demonstrate the actual presence of nitrone spin adducts in the cochlea following simultaneous exposure to noise and CO. Using electrophysiological end-points, the protective effects of the nitrone spin-trapping agent a-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) were assessed following combined exposure of adult male Long Evans hooded rats to noise and CO. In addition, an ex-vivo evaluation of POBN spin adducts was done by electron paramagnetic resonance spectroscopy (EPR). The noise used was octave band noise with center frequency 13.6 kHz at 100 dBLin for a duration of 2 h. The level of CO used was 1200 ppm. Electrophysiological results demonstrate that POBN protects against combined exposure to noise plus CO. The EPR study demonstrates POBN spin adducts in the cochleae of animals exposed to noise plus CO. Therefore, this study provides evidence to the hypothesis that ototoxicity due to noise plus CO exposure is mediated via free radicals. [Description provided by NIOSH]
• Subjects:
  Carbon Monoxide Free Radicals Noise Noise, Occupational Occupational Health Safety
• Keywords:
  A-(4-Pyridyl-1-oxide)-N-tert-butylnitrone Auditory Auditory System Author Keywords: Free Radical Carbon Monoxide Cochlea Electron Paramagnetic Resonance Spectroscopy Exposure Assessment Free Radicals Noise Exposure Ototoxicity Spin-trap

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• ISSN:
  0378-5955
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Oklahoma ; OSHA Region 6
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  113-122
• Volume:
  161
• Issue:
  1
• NIOSHTIC Number:
  nn:20057881
• Citation:
  Hear Res 2001 Nov; 161(1-2):113-122
• Contact Point Address:
  Deepa B. Rao, 1110 N.Stonewall, Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
• Email:
  deepa-bandi-rao@ouhsc.edu
• CAS Registry Number:
  Carbon monoxide (CAS RN 630-08-0)
• Federal Fiscal Year:
  2002
• NORA Priority Area:
  Disease and Injury: Hearing Loss
• Performing Organization:
  University of Oklahoma, Health Sciences Center, Oklahoma Center for Toxicology, Oklahoma City, Oklahoma
• Peer Reviewed:
  True
• Start Date:
  19970901
• Source Full Name:
  Hearing Research
• End Date:
  20000831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:7dc847c09aedf140bc731323e8446b4703641ae07d6ad9e7b7238120dab30b8f7dcaa9b938d34d035f87873a0fe7fec262d5d13dcaf290925445e82b6de3b57d
• Download URL:
  https://stacks.cdc.gov/view/cdc/215087/cdc_215087_DS1.pdf
• File Type:
  [PDF - 168.02 KB ]