Hydrogen Gas Protects Hearing from Loud Noise Damage in Animal Study
- Authors
- Anette Elisabeth Fransson, Pernilla Videhult Pierre, Mårten Risling, Göran Frans Emanuel Laurell
- Journal
- Frontiers in Cellular Neuroscience
- Year
- 2021
- DOI
- 10.3389/fncel.2021.658662
- Study Type
- Guinea Pig
- Outcome
- Positive
- Peer Reviewed
- Yes
- Country
- Sweden
- Health Condition
- Noise-Induced Hearing Loss
- Body System
- Auditory
TL;DR
Inhaling hydrogen gas can help protect guinea pigs' ears from noise-induced hearing loss and damage to ear cell structures.
Key Finding
Guinea pigs treated with inhaled hydrogen gas after noise exposure showed significantly better hearing thresholds and preserved inner and outer hair cell structures in the cochlea (the hearing part of the inner ear) compared to untreated controls.
Summary
Researchers exposed guinea pigs to loud noise and then gave some animals hydrogen gas to breathe for one hour. They measured hearing ability and examined ear structures over two weeks. Guinea pigs that received hydrogen gas showed better hearing preservation and less damage to the sound-sensing cells in their ears compared to animals that breathed regular air, suggesting hydrogen's antioxidant properties (ability to neutralize harmful molecules) may protect against noise-related hearing loss.
Practical Takeaway
While this animal study suggests hydrogen inhalation may help protect hearing after noise exposure, it was conducted only in guinea pigs and does not yet prove the same effect would occur in humans. Human clinical trials are needed before hydrogen gas can be considered a viable rescue treatment for noise-induced hearing loss in people.
Abstract
Noise exposure is the most important external factor causing acquired hearing loss in humans, and it is strongly associated with the production of reactive oxygen species (ROS) in the cochlea. Several studies reported that the administration of various compounds with antioxidant effects can treat oxidative stress-induced hearing loss. However, traditional systemic drug administration to the human inner ear is problematic and has not been successful in a clinical setting. Thus, there is an urgent need to develop rescue treatment for patients with acute acoustic injuries. Hydrogen gas has antioxidant effects, rapid distribution, and distributes systemically after inhalation.The purpose of this study was to determine the protective efficacy of a single dose of molecular hydrogen (H2) on cochlear structures. Guinea pigs were divided into six groups and sacrificed immediately after or at 1 or 2 weeks. The animals were exposed to broadband noise for 2 h directly followed by 1-h inhalation of 2% H2 or room air. Electrophysiological hearing thresholds using frequency-specific auditory brainstem response (ABR) were measured prior to noise exposure and before sacrifice. ABR thresholds were significantly lower in H2-treated animals at 2 weeks after exposure, with significant preservation of outer hair cells in the entire cochlea. Quantification of synaptophysin immunoreactivity revealed that H2 inhalation protected the cochlear inner hair cell synaptic structures containing synaptophysin. The inflammatory response was greater in the stria vascularis, showing increased Iba1 due to H2 inhalation.Repeated administration of H2 inhalation may further improve the therapeutic effect. This animal model does not reproduce conditions in humans, highlighting the need for additional real-life studies in humans.