title: Inhaled hydrogen gas therapy for prevention of noise-induced hearing loss through reducing reactive oxygen species.
abstract: Reactive oxygen species (ROS) that form in the inner ear play an important role in noise-induced hearing loss (NIHL). Recent studies have revealed that molecular hydrogen (H2) has great potential for reducing ROS. In this study, we examined the potential of hydrogen gas to protect against NIHL. We tested this hypothesis in guinea pigs with 0.5%, 1.0% and 1.5% H2 inhalation in air for 5h a day after noise exposure, for five consecutive days. All animals underwent measurements for auditory brainstem response after the noise exposure; the results revealed that there was a better improvement in the threshold shift for the 1.0% and 1.5% H2-treated groups than the non-treated group. Furthermore, outer hair cell (OHC) loss was examined 7 days after noise exposure. A significantly higher survival rate of OHCs was observed in the 1.0% and 1.5% H2-treated group as compared to that of the non-treated group in the basal turn. Immunohistochemical analyses for 8-hydroxy-2'-deoxyguanosine (8-OHdG) were performed to examine the amount of oxidative DNA damage. While strong immunoreactivities against 8-OHdG were observed of the non-treated group, the H2-treated group showed decreased immunoreactivity for 8-OHdG. These findings strongly suggest that inhaled hydrogen gas protects against NIHL.
authors.affiliation: Department of Otolaryngology, National Defense Medical College, Saitama, Japan.
authors.forename: Takaomi
authors.initials: T
authors.lastname: Kurioka
authors.affiliation: Department of Otolaryngology, National Defense Medical College, Saitama, Japan. Electronic address: takeshim@ndmc.ac.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Matsunobu
authors.affiliation: Department of Anesthesiology, National Defense Medical College, Saitama, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Satoh
authors.affiliation: Department of Otolaryngology, National Defense Medical College, Saitama, Japan.
authors.forename: Katsuki
authors.initials: K
authors.lastname: Niwa
authors.affiliation: Department of Otolaryngology, National Defense Medical College, Saitama, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Shiotani
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000280:Administration, Inhalation; D000818:Animals; D002452:Cell Count; D002470:Cell Survival / Q000187:drug effects; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects*; D005260:Female; D006168:Guinea Pigs; D018072:Hair Cells, Auditory, Outer / Q000187:drug effects*; D006317:Hearing Loss, Noise-Induced / Q000503:physiopathology / Q000517:prevention & control*; D006859:Hydrogen / Q000494:pharmacology / Q000627:therapeutic use*; D018696:Neuroprotective Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D018696:Neuroprotective Agents; D017382:Reactive Oxygen Species; D006859:Hydrogen; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine
keywords: Hydrogen; Noise-induced hearing loss (NIHL); Reactive oxygen species (ROS)