Abstract | OBJECTIVE: Despite efforts at public health awareness and stringent industrial standards for hearing protection, noise-induced hearing loss (NIHL) remains a formidable public health concern. Although many antioxidants have proven to be beneficial in the laboratory for prevention of permanent NIHL, low-dose combinations of compounds with different biochemical mechanisms of action may allow long-term administration with fewer side effects and equal efficacy. The mixture of D- methionine and N-acetyl-L-cysteine administered at levels less than 10% of standard dosing has not been previously reported. STUDY DESIGN: Twenty-six female adult Chinchilla laniger were placed in 4 study groups, consisting of (1) a group receiving combination 12.5 mg/kg each D- methionine and N-acetyl-L-cysteine (DMET/NAC group), (2) a group receiving 12.5 mg/kg D- methionine (DMET-only group), (3) a group receiving 12.5 mg/kg N-acetyl-L-cysteine (NAC-only group), and (4) saline controls. SETTING: Laboratory. SUBJECTS AND METHODS: All groups received twice-daily intraperitoneal injections 2 days prior to noise exposure, 1 hour before and after exposure on day 3, and for 2 days subsequently, totaling 10 doses of 125 mg/kg for each antioxidant over 5 days. RESULTS: Although NAC-only animals paralleled saline control recovery during 3 weeks, the DMET-only group revealed gradual improvement with statistically significant recovery in the middle frequencies. The DMET/NAC group showed significant improvement at most frequencies compared with controls (P < .001 and P < .05). CONCLUSION: Significant recovery of hearing was observed following continuous noise exposure with either DMET only or a combination of low-dose DMET/NAC, demonstrating a considerably lower dose of antioxidants required than previously reported for hearing recovery following acoustic trauma.
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Authors | Royce E Clifford, John K M Coleman, Ben J Balough, Jianzhong Liu, Richard D Kopke, Ronald L Jackson |
Journal | Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery
(Otolaryngol Head Neck Surg)
Vol. 145
Issue 6
Pg. 999-1006
(Dec 2011)
ISSN: 1097-6817 [Electronic] England |
PMID | 21750343
(Publication Type: Comparative Study, Journal Article, Research Support, U.S. Gov't, Non-P.H.S.)
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Chemical References |
- Methionine
- Acetylcysteine
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Topics |
- Acetylcysteine
(administration & dosage)
- Animals
- Auditory Threshold
(drug effects)
- Chinchilla
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Drug Administration Schedule
- Drug Therapy, Combination
- Evoked Potentials, Auditory, Brain Stem
(drug effects)
- Female
- Hearing Loss, Noise-Induced
(drug therapy, prevention & control)
- Injections, Intraperitoneal
- Methionine
(administration & dosage)
- Random Allocation
- Reference Values
- Treatment Outcome
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