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Published on: March 10, 2023
Round window membrane in young and aged C57BL/6 mice
Yoko Kitamura1, Masa aki Teranishi, Michihiko Sone
1Department of Otorhinolaryngology, Nagoya University, Graduate School of Medicine, 65, Tsurumai-cho, Showa-ku, 466-8550, Nagoya, Japan. kitayoko@tsuru.med.nagoya-u.ac.jp
Abstract:
Although there have been many studies on the round window membrane (RWM), little information has been reported about changes in the membrane associated with aging. We have undertaken morphological studies of RWMs using young (7-8 weeks old) and aged (27-29 months old) C57BL/6 mice. The RWM was thinner in mice from the aged group compared with that of the young group. The cell density in the epithelial and inner layers was also reduced in the aged group. In the middle layer of the RWM in aged mice, transmission electron microscopy revealed many degenerated short and thick elastic fibers. Confocal laser microscopy using fluorescein isothiocyanate(FITC)-wheat germ agglutinin (WGA) staining was used to identify WGA-positive fibers in the middle layer of the RWM, which changed in a similar manner to the fibers in aging skin.
Insights
Aging causes significant changes in the round window membrane (RWM), including thinning and degeneration of elastic fibers. These findings highlight age-related RWM alterations, impacting auditory health.
Area of Science:
- Otolaryngology
- Gerontology
- Cell Biology
Background:
- The round window membrane (RWM) plays a crucial role in cochlear mechanics.
- Limited research exists on age-related morphological changes in the RWM.
Purpose of the Study:
- To investigate the morphological alterations of the RWM in aged mice compared to young mice.
- To characterize age-associated changes in RWM structure and composition.
Main Methods:
- Morphological analysis of RWMs from young (7-8 weeks) and aged (27-29 months) C57BL/6 mice.
- Transmission electron microscopy (TEM) to examine elastic fiber degeneration.
- Confocal laser microscopy with FITC-wheat germ agglutinin (WGA) staining to assess fiber changes.
Main Results:
- Aged RWMs were significantly thinner than those in young mice.
- Reduced cell density was observed in the epithelial and inner layers of aged RWMs.
- TEM revealed degenerated, short, and thick elastic fibers in the middle layer of aged RWMs, similar to aging skin.
Conclusions:
- Aging leads to significant thinning and cellular changes in the RWM.
- Degeneration of elastic fibers in the RWM middle layer is a key feature of aging.
- These RWM changes associated with aging may have implications for auditory function.
