Role of Microtubule Network in the Passive Anisotropic Viscoelasticity of Healthy Right Ventricle
Role of Microtubule Network in the Passive Anisotropic Viscoelasticity of Healthy Right Ventricle
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DOI：
10.1115/1.4064685
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发表时间：
2024-07-01
影响因子：
1.7
通讯作者：
Wang，Zhijie
中科院分区：
文献类型：
--
作者：
LeBar，Kristen;Liu，Wenqiang;Wang，Zhijie
心肌细胞是粘弹性的，是右心室（RV）力学的关键决定因素。在细胞内，微管被发现会影响离体心肌细胞或小梁的粘弹性;它们是否有助于组织水平的粘弹性尚不清楚。我们的目标是揭示健康RV的被动各向异性粘弹性中微管网络的作用。在舒张早期（6%）和舒张末期（15%）应变水平下，以及在亚生理和生理拉伸速率下，对健康RV游离壁（RVFW）进行等双轴应力松弛试验。在基线和去除微管网络后评估粘弹性。此外，应用准线性粘弹（QLV）模型来描述微管对RVFW松弛行为的贡献。去除微管网络后，RVFW弹性和粘度在舒张早期应变水平和两个方向上都降低。弹性的降低在纵向方向上更强，而粘度的变化程度在方向之间是相等的。舒张晚期应变水平下RVFW粘弹性无明显变化。最后，建模表明，组织的松弛强度降低了微管网络的去除，但这种变化只存在于较晚的时间尺度。这些新的发现表明，在生理条件下RVFW被动力学的细胞骨架丝的关键作用。
Cardiomyocytes are viscoelastic and key determinants of right ventricle (RV) mechanics. Intracellularly, microtubules are found to impact the viscoelasticity of isolated cardiomyocytes or trabeculae; whether they contribute to the tissue-level viscoelasticity is unknown. Our goal was to reveal the role of the microtubule network in the passive anisotropic viscoelasticity of the healthy RV. Equibiaxial stress relaxation tests were conducted in healthy RV free wall (RVFW) under early (6%) and end (15%) diastolic strain levels, and at sub- and physiological stretch rates. The viscoelasticity was assessed at baseline and after the removal of microtubule network. Furthermore, a quasi-linear viscoelastic (QLV) model was applied to delineate the contribution of microtubules to the relaxation behavior of RVFW. After removing the microtubule network, RVFW elasticity and viscosity were reduced at the early diastolic strain level and in both directions. The reduction in elasticity was stronger in the longitudinal direction, whereas the degree of changes in viscosity were equivalent between directions. There was insignificant change in RVFW viscoelasticity at late diastolic strain level. Finally, the modeling showed that the tissue's relaxation strength was reduced by the removal of the microtubule network, but the change was present only at a later time scale. These new findings suggest a critical role of cytoskeleton filaments in RVFW passive mechanics in physiological conditions.