Age-related changes in the lateral cochlear wall component cells Three-dimensional analysis by serial section scanning electron microscopy

• Project/Area Number: 18K16835
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 56050:Otorhinolaryngology-related
• Research Institution: Niigata University
• Principal Investigator: Shodo Ryusuke 新潟大学, 医歯学総合病院, 専任助教 (00815764)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000); Fiscal Year 2020: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2018: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
• Keywords: 加齢性難聴 / 内耳 / 蝸牛 / 組織学 / 電子顕微鏡 / 立体構造

Outline of Final Research Achievements

Two-month-old rat cochleae were removed, fixed, demineralized, embedded in Epon resin, semi-ultrathin serial sections were prepared, and images taken by scanning electron microscopy, and images were reconstructed three-dimensionally on a personal computer. The same process was also attempted for 6-, 12-, and 24-month-old rats, but the preparation of samples for electron microscopy was difficult. We did not reach the stage of statistical examination of the volume of each cell, occupancy in the outer lateral wall of the cochlea, and differences in basal, mid, and apical rotations for rats of different ages.

Academic Significance and Societal Importance of the Research Achievements

蝸牛外側壁は血管条を中心として内リンパ液の特殊な高電位かつ高カリウムイオン環境に不可欠であることが知られており、その組織学的な変化は加齢性難聴に大きく影響していると推測される。通常は立体的観察が困難である蝸牛外側壁を、準超薄連続切片を走査型電子顕微鏡で観察し3次元再構築を行うことで立体像を得ることができ、蝸牛外側壁を構成する諸細胞の３次元像を解明できると考えられる。本研究の中では月齢毎のラットの差異について決定的な所見は得ることができなかったが、この手法の発展は加齢性難聴の病態解明、予防法または治療法の開発につながることが期待される。