کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4356379 | 1615675 | 2007 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Oxidative stress pathways in the potentiation of noise-induced hearing loss by acrylonitrile
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علم عصب شناسی
سیستم های حسی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
We hypothesize that the disruption of antioxidant defenses is a key mechanism whereby chemical contaminants can potentiate noise-induced hearing loss (NIHL). This hypothesis was tested using acrylonitrile (ACN), a widely used industrial chemical whose metabolism is associated with glutathione (GSH) depletion and cyanide (CN) generation. CN, in turn, can inhibit Cu/Zn superoxide dismutase (SOD). We have shown previously that ACN potentiates NIHL, even with noise exposure approaching permissible occupational levels. However, the relative involvement of GSH depletion and/or CN production in this potentiation is still unknown. In this study, we altered these metabolic pathways pharmacologically in order to further delineate the role of specific antioxidants in the protection of the cochlea. We investigated the effects of sodium thiosulfate (STS), a CN inhibitor, 4-methylpyrazole (4MP), a drug that blocks CN generation by competing with CYP2E1, and l-N-acetylcysteine (l-NAC), a pro-GSH drug, in order to distinguish between GSH depletion and CN production as the mechanism responsible for potentiation of NIHL by ACN. Long-Evans rats were exposed to an octave-band noise (97Â dB SPL, 4Â h/day, 5 days) and ACN (50Â mg/kg). Separate pre-treatments with STS (150Â mg/kg), 4MP (100Â mg/kg) and l-NAC (4Â ÃÂ 400Â mg/kg) all dramatically reduced blood CN levels, but only l-NAC significantly protected GSH levels in both the liver and the cochlea. Concurrently, only l-NAC treatment decreased the auditory loss and hair cell loss resulting from ACNÂ +Â noise, suggesting that GSH is involved in the protection of the cochlea against reactive oxygen species generated by moderate noise levels. On the other hand, CN does not seem to be involved in this potentiation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Hearing Research - Volume 224, Issues 1â2, February 2007, Pages 61-74
Journal: Hearing Research - Volume 224, Issues 1â2, February 2007, Pages 61-74
نویسندگان
Benoît Pouyatos, Caroline Gearhart, Alisa Nelson-Miller, Sherry Fulton, Laurence Fechter,