外柱细胞软化对Corti器感音影响的生物力学研究

Biomechanical study on effect of outer pillar cells softening on sound sensing of organ of Corti

Corti器的感音过程容易受到内部结构属性变化的影响。外柱细胞血管舒张刺激磷蛋白缺失会减缓肌动蛋白丝的形成,从而产生听力延迟。本研究运用COMSOL建立三维有限元模型研究肌动蛋白缺失导致外柱细胞软化时,Corti器感音过程中基底膜和外毛细胞与Deiters细胞结合点的力学行为变化。结果表明,外柱细胞软化会削弱外毛细胞主动力对基底膜位移增益的放大作用,但削弱作用并不会立即产生,Corti器存在维持正常功能的"缓冲"阶段。在100 dB和120 dB之间可能存在一个声压级临界值,在该临界值两侧外柱细胞软化对基底膜应力变化的影响是截然相反的。另外外柱细胞软化对不同外毛细胞与Deiters细胞结合点力学行为的影响也不同,位移增益优先级会因此产生改变。

The sound sensing process of organ of Corti is easily affected by changes in internal structural properties.Loss of vasodilation-stimulated phosphoprotein in the outer pillar cells slows the formation of actin filaments,resulting in hearing delay.In the study,COMSOL is used to establish a three-dimensional finite element model to investigate the changes in the mechanical behaviors of the basilar membrane and the junction between outer hair cells and Deiters cells during the sound sensing process of organ of Corti under the condition of outer pillar cells softening caused by the absence of actin.The result shows that the softening of outer pillar cells weakens the magnification of the active power of outer hair cells on the displacement gain of the basilar membrane,but the weakening doesn’t occur immediately,which means the organ of Corti has a"buffer"stage to maintain normal functions.There may be a critical value of sound pressure level between 100 dB and120 dB.In two sides of this critical value,the effects of the softening of outer pillar cells on the stress of the basilar membrane are completely opposite.In addition,the softening of outer pillar cells has different effects on the mechanical behavior of different junctions between outer hair cells and Deiters cells,and the priority of displacement gain changes accordingly.