Strains induced in the vagina by smooth muscle contractions
Strains induced in the vagina by smooth muscle contractions
复制标题
DOI：
10.1016/j.actbio.2021.05.015
复制
发表时间：
2021-07-05
影响因子：
9.7
通讯作者：
De Vita, Raffaella
中科院分区：
文献类型：
--
作者：
Huntington, Alyssa;Abramowitch, Steven D.;De Vita, Raffaella
阴道收缩的能力产生了一系列活跃的机械特性，这些特性有助于该器官在体内的复杂功能。人们早就认识到阴道形态的区域差异，但阴道在收缩过程中经历的巨大异质变形从未被量化。此外，关于阴道两个主要解剖方向（纵向（LD）和圆周方向（CD））的收缩性差异尚未达成共识。在这项研究中，来自健康处女大鼠（n = 15）的方形阴道标本在 1.0、1.1、1.2 和 1.3 四个等双轴拉伸下进行等距平面双轴测试。在每次拉伸时用高浓度钾溶液诱导收缩。数字图像相关方法用于在收缩期间进行全场应变测量。研究发现，在收缩过程中，阴道沿 LD 方向承受的压缩应变、拉伸应变和收缩力明显高于沿 CD 方向。具体来说，当计算所有应用的等双轴拉伸时，沿 LD 的平均（+/- 标准差）绝对最大压缩应变为 -（13.43 +/- 1.56）％，沿 CD 为 -（3.19 +/- 0.25）％，沿 LD 的平均绝对最大拉伸应变为（10.92 +/- 1.73）％，和（3.62 +/- 0.57）％沿 CD 的平均最大收缩力为 6.24 +/- 0.55 mN（沿 LD）和 3.35 +/- 0.56 mN（沿 CD）。此外，阴道组织似乎在近端区域受到压缩，在远端区域受到张力，同时保持恒定的等双轴拉伸。需要充分研究健康阴道的主动机械特性，以便预防阴道收缩力的有害改变，例如由盆底疾病和当前治疗策略引起的改变。重要性说明 几位研究人员已经使用单轴拉伸测试方法测量了阴道的收缩力。与之前的研究不同，本研究对阴道标本进行平面双轴测试，同时测量由平滑肌收缩引起的阴道全场应变。研究发现，阴道在纵向上产生的收缩应变和力明显大于在圆周方向上的收缩应变和力。了解健康阴道的收缩力学对于了解盆腔器官脱垂和手术网的使用对阴道平滑肌功能的有害影响至关重要。 (c) 2021 Acta Materialia Inc. 由 Elsevier Ltd 出版。保留所有权利。
The ability of the vagina to contract gives rise to a set of active mechanical properties that contribute to the complex function of this organ in-vivo . Regional differences in the morphology of the vagina have been long recognized, but the large heterogeneous deformations that the vagina experiences during contractions have never been quantified. Furthermore, there is no consensus regarding differences in contractility along the two primary anatomical directions of the vagina: the longitudinal direction (LD) and the circumferential direction (CD). In this study, square vaginal specimens from healthy virgin rats ( n = 15 ) were subjected to isometric planar biaxial tests at four equi-biaxial stretches of 1.0, 1.1, 1.2, and 1.3. Contractions were induced at each stretch by a high concentration potassium solution. The digital image correlation method was used to perform full-field strain measurements during contractions. The vagina was found to undergo significantly higher compressive strains, tensile strains, and contractile forces along the LD than along the CD during contractions. Specifically, when computed over all the applied equi-biaxial stretches, mean (+/- std. dev.) absolute maximum compressive strains were-(13.43 +/- 1.56) % along the LD and-(3.19 +/- 0.25) % along the CD, mean absolute maximum tensile strains were (10.92 +/- 1.73) % along the LD and (3.62 +/- 0.57) % along the CD, and mean maximum contractile forces were 6.24 +/- 0.55 mN along the LD and 3.35 +/- 0.56 mN along the CD. Moreover, the vaginal tissue appeared to undergo compression in the proximal region and tension in the distal region while kept at constant equi-biaxial stretches. The active mechanical properties of the healthy vagina need to be fully investigated so that detrimental alterations in vaginal contractility, such as those caused by pelvic floor disorders and current treatment strategies, can be prevented. Statement of significance Contractile forces of the vagina have been measured by several investigators using uniaxial tensile testing methods. Unlike previous studies, in this study planar-biaxial tests of vaginal specimens were performed while the full-field strains of the vagina, as induced by smooth muscle contraction, were measured. The vagina was found to generate significantly larger contractile strains and forces in the longitudinal direction than in the circumferential direction. Knowledge of the contractile mechanics of the healthy vagina is essential to understand the detrimental effects that pelvic organ prolapse and the use of surgical meshes have on the functionality of smooth muscle in the vagina. (c) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.