Hydrogen Gas Protects Hearing from Loud Noise Damage in Animal Study
- Authors
- Takaomi Kurioka, Takeshi Matsunobu, Yasushi Satoh, Katsuki Niwa, Akihiro Shiotani
- Journal
- Neuroscience Research
- Year
- 2014
- DOI
- 10.1016/j.neures.2014.08.009
- Study Type
- Guinea Pig
- Outcome
- Positive
- Peer Reviewed
- Yes
- Country
- Japan
- Health Condition
- Noise-Induced Hearing Loss
- Body System
- Auditory
TL;DR
Breathing in hydrogen gas can help protect against hearing loss caused by loud noise.
Key Finding
Guinea pigs treated with inhaled hydrogen gas at 1.0% and 1.5% concentrations showed significantly better hearing recovery and higher survival rates of inner ear hair cells after noise exposure compared to untreated animals.
Summary
Researchers exposed guinea pigs to loud noise and then gave some of them inhaled hydrogen gas (at 1.0% or 1.5% concentration) for 5 hours daily for five days. Hydrogen gas is thought to reduce harmful molecules called reactive oxygen species (ROS) that damage cells. The guinea pigs that received hydrogen gas showed better hearing recovery and had more surviving inner ear cells (called outer hair cells) compared to those that didn't receive it. The study suggests hydrogen gas may protect hearing from noise damage by reducing oxidative stress (cellular damage from ROS).
Practical Takeaway
While this animal study suggests hydrogen gas inhalation may help protect hearing from noise damage through antioxidant mechanisms, it is only preliminary evidence in guinea pigs. Human studies would be needed to determine if these results apply to people, and the optimal dose and delivery method for humans remain unknown.
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.