Reduction of noise-induced hearing loss using L-NAC and salicylate in the chinchilla

Hear Res. 2000 Nov;149(1-2):138-46. doi: 10.1016/s0378-5955(00)00176-3.

Abstract

The effects of a combination of two antioxidant compounds were studied in a chinchilla model of noise-induced hearing loss. After obtaining baseline hearing thresholds using inferior colliculus evoked potentials, chinchillas were exposed for 6 h to octave band noise centered at 4 kHz (105 dB SPL). Post-noise thresholds were obtained 1 h after the noise exposure, and then animals received either saline or salicylate and N-L-acetylcysteine combination. Another group received antioxidant treatment 1 h prior to noise. Hearing was tested at 1, 2 and 3 weeks post-noise. Subsequently, the cochleae were harvested, and cytocochleograms were prepared. There was a 20-40 dB SPL threshold shift at 3 weeks for tested controls. Permanent threshold shifts (PTS) were significantly reduced (P<0.05) to approximately 10 dB for the pre-treatment group at week 3. The PTS for the post-treatment group at week 3 was similar to the pre-treatment group at 1 and 2 kHz (0-10 dB) but was intermediate between the control and pre-treatment groups at 4 and 8 kHz (23 dB). Animals pre-treated with antioxidant had a significant reduction in hair cell loss but those post-treated with antioxidant had no protection from hair cell loss. These findings demonstrate the feasibility of reduction of noise-induced hearing loss using clinically available antioxidant compounds.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acetylcysteine / therapeutic use*
  • Animals
  • Audiometry
  • Auditory Threshold / drug effects
  • Cell Count
  • Chinchilla
  • Drug Combinations
  • Hair Cells, Auditory / drug effects
  • Hair Cells, Auditory / pathology
  • Hearing Loss, Noise-Induced / drug therapy*
  • Hearing Loss, Noise-Induced / physiopathology
  • Salicylates / therapeutic use*

Substances

  • Drug Combinations
  • Salicylates
  • Acetylcysteine