Establishment of a Biaxial Testing System for Characterization of Right Ventricle Viscoelasticity Under Physiological Loadings
Establishment of a Biaxial Testing System for Characterization of Right Ventricle Viscoelasticity Under Physiological Loadings
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DOI：
10.1007/s13239-024-00722-5
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发表时间：
2024-03-11
影响因子：
1.8
通讯作者：
Wang，Zhijie
中科院分区：
文献类型：
--
作者：
Roth，Kellan;Liu，Wenqiang;Wang，Zhijie
目的研究表明，心肌粘弹性对心脏收缩和舒张功能有影响。然而，对心室壁，特别是右心室壁的粘弹性的研究还很有限。此外，心室被动粘弹性的研究仅限于大型动物，缺乏啮齿类动物的数据。为了填补这一知识空白，本研究的目的是开发一种双轴测试仪，诱导高速生理变形，以表征大鼠RVs.MethodsThe双轴测试系统的被动粘弹性制作，使大鼠心室组织在生理应变率的平面变形是可能的。使用各向同性聚二甲基硅氧烷（PDMS）片材对测试系统进行了验证。接下来，粘弹性测量在健康的大鼠RV自由壁进行等双轴循环正弦载荷和应力relaxations.ResultsThe双轴测试仪的一致性，准确性和稳定性，从PDMS样品的测量确认。在亚生理频率（0.1 Hz）和生理频率（1-8 Hz）之间，右心室的粘弹性变化显著。从磁滞回线分析，我们发现，随着频率的增加，弹性和粘度增加的两个方向。有趣的是，存储能量与耗散能量的比率（Wd/Ws）在0.1-5 Hz处保持恒定。我们没有观察到健康RV粘弹性之间的纵向和圆周directions.ConclusionThis工作提供了一个新的实验工具，以量化被动，双轴粘弹性心室游离壁在小型和大型动物之间的显着差异。动态力学测试显示了健康大鼠RV的频率依赖性弹性和粘性行为。但耗散能与储能的比例在频率之间保持不变。这些发现提供了新的基线信息的被动粘弹性健康RV在成年大鼠。
PurposePrior studies have indicated an impact of cardiac muscle viscoelasticity on systolic and diastolic functions. However, the studies of ventricular free wall viscoelasticity, particularly for that of right ventricles (RV), are limited. Moreover, investigations on ventricular passive viscoelasticity have been restricted to large animals and there is a lack of data on rodent species. To fill this knowledge gap, this study aims to develop a biaxial tester that induces high-speed physiological deformations to characterize the passive viscoelasticity of rat RVs.MethodsThe biaxial testing system was fabricated so that planar deformation of rat ventricle tissues at physiological strain rates was possible. The testing system was validated using isotropic polydimethylsiloxane (PDMS) sheets. Next, viscoelastic measurements were performed in healthy rat RV free walls by equibiaxial cyclic sinusoidal loadings and stress relaxation.ResultsThe biaxial tester’s consistency, accuracy, and stability was confirmed from the PDMS samples measurements. Moreover, significant viscoelastic alterations of the RV were found between sub-physiological (0.1 Hz) and physiological frequencies (1–8 Hz). From hysteresis loop analysis, we found as the frequency increased, the elasticity and viscosity were increased in both directions. Interestingly, the ratio of storage energy to dissipated energy (Wd/Ws) remained constant at 0.1–5 Hz. We did not observe marked differences in healthy RV viscoelasticity between longitudinal and circumferential directions.ConclusionThis work provides a new experimental tool to quantify the passive, biaxial viscoelasticity of ventricle free walls in both small and large animals. The dynamic mechanical tests showed frequency-dependent elastic and viscous behaviors of healthy rat RVs. But the ratio of dissipated energy to stored energy was maintained between frequencies. These findings offer novel baseline information on the passive viscoelasticity of healthy RVs in adult rats.