Tear propagation in vaginal tissue under inflation
Tear propagation in vaginal tissue under inflation
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充气时阴道组织中的撕裂传播
DOI：
10.1016/j.actbio.2021.03.065
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发表时间：
2021
影响因子：
9.7
通讯作者：
De Vita, Raffaella
中科院分区：
文献类型：
--
作者：
McGuire, Jeffrey A.;Monclova, Jose L.;Coariti, Adriana C.;Stine, Caleb A.;Toussaint, Kimani C.;Munson, Jennifer M.;Dillard, David A.;De Vita, Raffaella
分娩时阴道撕裂极为常见，但对其长期严重影响妇女健康的研究却不足。阴道撕裂的机制仍然是未知的，他们的知识可能导致发展变革性的预防和治疗技术的产妇伤害。在这项研究中，使用定制的充气装置对沿器官轴向预先施加椭圆撕裂的整个大鼠阴道加压，产生大量撕裂传播。分析了泪液在传播过程中的大变形，利用数字图像相关技术计算了泪液周围的非线性应变。二次谐波产生显微镜用于检查胶原纤维组织在机械未测试和测试阴道标本。泪液在压力下变得越来越圆，缓慢地传播到最大压力，然后更快。环向应变明显大于轴向应变，并表现出区域和方向依赖的撕裂传播响应。影像学显示，随着压力的增加，最初胶原纤维沿轴向排列紊乱。泪滴尖端近区域的纤维向环向排列，阻碍泪滴传播。撕裂几何形状、区域应变和纤维取向的变化揭示了阴道组织固有的增韧机制。历史上，妇女的生殖健康一直没有得到充分的研究，尽管世界上孕产妇的伤害和死亡率令人震惊。通过提高我们对女性生殖器官所经历的巨大变形的有限理解，可以减少产妇受伤和残疾。本文首次介绍了阴道组织中撕裂传播的机制，以及撕裂附近和远处胶原蛋白微观结构的变化。一种新型的充气装置能够维持阴道的体内管状几何形状，同时传播预先施加的撕裂。通过测量撕裂几何形状、应变分布和胶原纤维的重新定向，研究了阴道对繁殖的增韧机制。这项研究借鉴了当前工程科学和力学领域的进展，目的是改善孕产妇保健。
Vaginal tearing at childbirth is extremely common yet understudied despite the long-term serious consequences on women’s health. The mechanisms of vaginal tearing remain unknown, and their knowledge could lead to the development of transformative prevention and treatment techniques for maternal injury. In this study, whole rat vaginas with pre-imposed elliptical tears oriented along the axial direction of the organs were pressurized using a custom-built inflation setup, producing large tear propagation. Large deformations of tears through propagation were analyzed, and nonlinear strains around tears were calculated using the digital image correlation technique. Second harmonic generation microscopy was used to examine collagen fiber organization in mechanically untested and tested vaginal specimens. Tears became increasingly circular under pressure, propagating slowly up to the maximum pressure and then more rapidly. Hoop strains were significantly larger than axial strains and displayed a region- and orientation-dependent response with tear propagation. Imaging revealed initially disorganized collagen fibers that aligned along the axial direction with increasing pressure. Fibers in the near-regions of tear tips aligned toward the hoop direction, hampering tear propagation. Changes in tear geometry, regional strains, and fiber orientation revealed the inherent toughening mechanisms of the vaginal tissue.Statement of significanceWomen’s reproductive health has historically been understudied despite alarming maternal injury and mortality rates in the world. Maternal injury and disability can be reduced by advancing our limited understanding of the large deformations experienced by women’s reproductive organs. This manuscript presents, for the first time, the mechanics of tear propagation in vaginal tissue and changes to the underlying collagen microstructure near to and far from the tear. A novel inflation setup capable of maintaining the in vivo tubular geometry of the vagina while propagating a pre-imposed tear was developed. Toughening mechanisms of the vagina to propagation were examined through measurements of tear geometry, strain distributions, and reorientation of collagen fibers. This research draws from current advances in the engineering science and mechanics fields with the goal of improving maternal health care.