Material properties of mouse cervical tissue in normal gestation
Material properties of mouse cervical tissue in normal gestation
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DOI：
10.1016/j.actbio.2016.03.005
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发表时间：
2016-05-01
影响因子：
9.7
通讯作者：
Myers, Kristin
中科院分区：
文献类型：
--
作者：
Yoshida, Kyoko;Mahendroo, Mala;Myers, Kristin
适当时机的宫颈重塑过程对于健康分娩至关重要，但由于获取人体组织样本很困难，因此对妊娠期间宫颈的材料特性变化知之甚少。啮齿动物模型的优势包括精确计时的怀孕组织和基因改造模型。然而，由于小鼠子宫颈尺寸小且几何形状复杂，确定其材料特性具有挑战性。本研究的目的是使用受微观结构启发的多孔纤维复合材料模型来量化正常小鼠妊娠时宫颈材料特性的变化。我们通过内管拉开张紧的缝线，以机械方式测试完整、完整、妊娠定时的小鼠子宫颈。为了解释我们的机械测试结果，我们进行了逆向有限元分析，并考虑了厚壁圆柱形组织的组合载荷状态。我们使用非线性优化方案将材料模型与本研究中先前的渗透膨胀数据和负载变形数据进行拟合，并通过预测一组单独的变形数据来验证模型。总体而言，所提出的多孔纤维复合材料模型捕获了小鼠子宫颈在大变形下的机械行为。宫颈材料参数的演变表明，在正常小鼠妊娠中，宫颈在 19 天妊娠期的第 6 天到第 12 天之间开始软化。与胶原纤维硬度相关的材料参数从妊娠第 6 天的 3.4 MPa 下降到妊娠第 18 天的 9.7e-4 MPa，而基质硬度从 2.6e-1 MPa 下降到 7.0e-4 MPa。 意义声明加速宫颈重塑可能导致极度早产。然而，由于怀孕人体组织样本有限，人们对怀孕期间子宫颈的材料特性变化知之甚少。啮齿动物模型克服了这一限制并提供了妊娠定时样本。由于小鼠子宫颈尺寸小且几何形状复杂，测量怀孕期间小鼠子宫颈的材料特性变化具有挑战性。在这里，我们建立了一个组合的实验和建模框架。我们使用这个框架来确定正常小鼠妊娠期间宫颈物质特性的变化。我们提出了对整个完整宫颈组织样本进行机械测试的实验方法。我们将多孔纤维复合材料模型与机械数据进行拟合，结果表明，小鼠子宫颈在 19 天妊娠期的第 6 天到第 12 天之间开始软化。 (C) 2016 Acta Materialia Inc. 由 Elsevier Ltd 出版。保留所有权利。
An appropriately timed cervical remodeling process is critical for a healthy delivery, yet little is known about the material property changes of the cervix in pregnancy because obtaining human tissue samples is difficult. Rodent models offer advantages including accurately timed pregnant tissues and genetically altered models. Determining the material properties of the mouse cervix, however, is challenging because of its small size and complex geometry. The aim of this study is to quantify cervical material property changes in a normal mouse pregnancy using a microstructurally-inspired porous fiber composite model. We mechanically test intact, whole, gestation-timed mouse cervix by pulling apart tensioned sutures through its inner canal. To interpret our mechanical testing results, we conduct an inverse finite element analysis, taking into account the combined loading state of the thick-walled cylindrical tissue. We fit the material model to previous osmotic swelling data and load-deformation data from this study using a nonlinear optimization scheme, and validate the model by predicting a separate set of deformation data. Overall, the proposed porous fiber composite model captures the mechanical behavior of the mouse cervix in large deformation. The evolution of cervical material parameters indicates that in a normal mouse pregnancy, the cervix begins to soften between day 6 and day 12 of a 19-day gestation period. The material parameter associated with the collagen fiber stiffness decreases from 3.4 MPa at gestation day 6 to 9.7e-4 MPa at gestation day 18, while the ground substance stiffness decreases from 2.6e-1 MPa to 7.0e-4 MPa.Statement of SignificanceAccelerated cervical remodeling can lead to extremely premature births. Little is known, however, about the material property changes of the cervix in pregnancy because pregnant human tissue samples are limited. Rodent models overcome this limitation and provide access to gestation-timed samples. Measuring the material property changes of the mouse cervix in pregnancy is challenging due to its small size and complex geometry. Here, we establish a combined experimental and modeling framework. We use this framework to determine the cervical material property changes throughout a normal mouse pregnancy. We present our experimental methods for mechanically testing whole, intact cervical tissue samples. We fit a porous fiber composite material model to the mechanical data and show that the mouse cervix begins to soften between day 6 and day 12 of a 19-day gestation period. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.