CONCLUSION: These findings indicate a strong protective effect of ALCAR and NAC on impulse noise-induced cochlear damage, and suggest the feasibility of using clinically available antioxidant compounds to protect the ear from acute acoustic injury. OBJECTIVE: Reactive oxygen species have been shown to play a significant role in noise-induced hearing loss. In the current study, the protective effects of two antioxidants, acetyl-L-carnitine (ALCAR) and N-L-acetylcysteine (NAC), were investigated in a chinchilla model of hearing loss resulting from impulse noise. It was hypothesized that pre- and post-treatment with these antioxidants would ameliorate the effects of impulse noise compared to saline-treated controls. MATERIAL AND METHODS: Eighteen animals were randomly assigned to 1 of 3 groups and exposed to impulse noise at a level of 155 dB peak SPL for 150 repetitions. ALCAR or NAC were administered twice daily (b.i.d.) for 2 days and 1 h prior to and 1 h following noise exposure, and then b.i.d. for the following 2 days. For the control group, saline was injected at the same time points. Auditory brainstem responses (ABRs) were recorded. Cochlear surface preparations were made to obtain cytocochleograms. RESULTS: Three weeks after exposure, permanent threshold shifts for the experimental groups were significantly reduced to approximately = 10-30 dB less than that for the control group (p < 0.01). Less hair cell loss was also observed in the ALCAR and NAC groups than in the control group.
CONCLUSION: These findings indicate a strong protective effect of ALCAR and NAC on impulse noise-induced cochlear damage, and suggest the feasibility of using clinically available antioxidant compounds to protect the ear from acute acoustic injury. OBJECTIVE:Reactive oxygen species have been shown to play a significant role in noise-induced hearing loss. In the current study, the protective effects of two antioxidants, acetyl-L-carnitine (ALCAR) and N-L-acetylcysteine (NAC), were investigated in a chinchilla model of hearing loss resulting from impulse noise. It was hypothesized that pre- and post-treatment with these antioxidants would ameliorate the effects of impulse noise compared to saline-treated controls. MATERIAL AND METHODS: Eighteen animals were randomly assigned to 1 of 3 groups and exposed to impulse noise at a level of 155 dB peak SPL for 150 repetitions. ALCAR or NAC were administered twice daily (b.i.d.) for 2 days and 1 h prior to and 1 h following noise exposure, and then b.i.d. for the following 2 days. For the control group, saline was injected at the same time points. Auditory brainstem responses (ABRs) were recorded. Cochlear surface preparations were made to obtain cytocochleograms. RESULTS: Three weeks after exposure, permanent threshold shifts for the experimental groups were significantly reduced to approximately = 10-30 dB less than that for the control group (p < 0.01). Less hair cell loss was also observed in the ALCAR and NAC groups than in the control group.
Authors: Robert A Floyd; Richard D Kopke; Chul-Hee Choi; Steven B Foster; Sabrina Doblas; Rheal A Towner Journal: Free Radic Biol Med Date: 2008-08-29 Impact factor: 7.376
Authors: C Spankovich; S K Griffiths; E Lobariñas; K E Morgenstein; S de la Calle; V Ledon; D Guercio; C G Le Prell Journal: Int J Audiol Date: 2014-03 Impact factor: 2.117
Authors: Sharon G Curhan; Konstantina M Stankovic; Roland D Eavey; Molin Wang; Meir J Stampfer; Gary C Curhan Journal: Am J Clin Nutr Date: 2015-09-09 Impact factor: 7.045