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Gas permeability of round window membrane
H Sasa1, K Nagahara, T Yamashita
1ENT Department, Kansai Medical University, Osaka, Japan.
Summary
Middle ear insufflation of pure oxygen effectively raises inner ear oxygen levels by crossing the round window membrane. This confirms an alternative oxygen supply route crucial for maintaining inner ear function.
Area of Science:
- Otolaryngology
- Physiology
- Biomedical Engineering
Background:
- Inner ear oxygenation is vital for auditory and vestibular function.
- The primary source of inner ear oxygen is typically considered to be via cochlear blood vessels.
Purpose of the Study:
- To investigate the potential for oxygen transport to the inner ear via the middle ear cavity.
- To measure perilymphatic oxygen tension following middle ear gas insufflation.
Main Methods:
- A polarographic technique was employed to measure oxygen tension in the scala tympani.
- Various gases were insufflated into the middle ear cavity of 7 guinea pigs.
- Specific focus on pure oxygen insufflation.
Main Results:
- Pure oxygen insufflation into the middle ear significantly elevated perilymphatic oxygen tension.
- Oxygen readily permeated the round window membrane, demonstrating a viable transport pathway.
- Confirmed oxygen transport to the inner ear independent of its intrinsic vasculature.
Conclusions:
- The middle ear cavity serves as a significant route for oxygen supply to the inner ear.
- This alternative oxygenation pathway via the round window membrane may play a role in maintaining inner ear function.
- Findings suggest potential therapeutic implications for conditions involving inner ear hypoxia.