ETH Zurich, Institute for Mechanical Systems, 8092 Zurich, Switzerland.
University Hospital Zurich, Department of Obstetrics, 8091 Zurich, Switzerland.
J Biomech. 2020 Jan 2;98:109419. doi: 10.1016/j.jbiomech.2019.109419. Epub 2019 Oct 16.
The amnion is considered to be the load-bearing part of the fetal membranes. We investigated the influence of osmolarity of the testing medium and hydration on its fracture toughness. Mode I fracture tests revealed that physiological variations in the bath osmolarity do not influence the tear resistance of amnion, while larger changes, i.e. from physiological saline solution to distilled water, lead to a significant reduction of the fracture toughness. Uniaxial tensile tests on collagen hydrogels confirmed the reduction in toughness, suggesting that lower bath osmolarity triggers changes in the failure properties of single collagen fibers. Prenatal surgeries, in particular fetoscopic procedures with partial amniotic carbon dioxide insufflation, might result in dehydration of the amnion. Dehydration induced a brittle behavior; however, subsequent rehydration for 15 min resulted in a similar tear resistance as for the fresh tissue.
羊膜被认为是胎儿膜的承重部分。我们研究了测试介质的渗透压和含水量对其断裂韧性的影响。I 型断裂试验表明，浴渗透压的生理变化不会影响羊膜的撕裂阻力，而较大的变化，即从生理盐水到蒸馏水，会导致断裂韧性显著降低。对胶原水凝胶的单轴拉伸试验证实了韧性的降低，表明较低的浴渗透压会引发单个胶原纤维失效特性的变化。产前手术，特别是带有部分羊膜二氧化碳充气的胎儿镜手术，可能导致羊膜脱水。脱水会导致羊膜变得脆弱；然而，随后的 15 分钟水合作用会使羊膜恢复到与新鲜组织相似的撕裂阻力。
