Basilar membrane and tectorial membrane stiffness in the CBA/CaJ mouse

Area of Science:

• Auditory Neuroscience
• Biophysics
• Mechanics of Hearing

Background:

• The mouse is a key model for studying cochlear function.
• Gene manipulation studies alter cochlear structures, necessitating baseline data on normal physical properties.

Purpose of the Study:

• To determine the physical properties, specifically stiffness and Young's modulus, of the basilar membrane (BM) and tectorial membrane (TM) in non-mutated CBA/Caj mice.
• To establish baseline data for the organ of Corti's physical characteristics.

Main Methods:

• Utilized the hemicochlea preparation of CBA/Caj mice.
• Measured stiffness and estimated Young's modulus of the TM and BM along the cochlear turns.

Main Results:

• Demonstrated a stiffness gradient along the cochlea for both TM and BM.
• Reported plateau stiffness values for TM (basal: 0.6 N/m, middle: 0.2 N/m, apical: 0.09 N/m) and BM (basal: 3.7 N/m, middle: 1.2 N/m, apical: 0.5 N/m).
• Provided Young's modulus estimations for TM (basal: 24.3 kPa, middle: 5.1 kPa, apical: 1.9 kPa) and BM (basal: 76.8 kPa, middle: 23.9 kPa, apical: 9.4 kPa).

Conclusions:

• The physical properties of the TM and BM exhibit a gradient along the mouse cochlea.
• The findings provide essential baseline data for the mechanical properties of the mouse organ of Corti.