University of Michigan, Transportation Research Institute, 2901 Baxter Rd., Ann Arbor, MI 48109, USA.
Placenta. 2012 Oct;33(10):776-81. doi: 10.1016/j.placenta.2012.06.012. Epub 2012 Jul 16.
Data on the strength of the utero-placental interface (UPI) would help improve understanding of the mechanisms of placental abruption (premature separation of the placenta from the uterus) during motor-vehicle crashes involving pregnant occupants. An ovine model was selected for study because like the human, its placenta has a villous attachment structure. Uteri with intact placentas were obtained from three sheep as by-products of another research study. The samples were harvested between 102 and 119 days of the 145-day gestational period. Rectangular specimens with areas measuring 15 mm × 5 mm were cut through the thickness of the placenta and uterus. Each subject provided eight samples, of which four were tested at a nominal strain rate of 0.10 strains/sec and the remainder was tested at a nominal strain rate of 1.0 strains/sec. Sutures were used to secure the uterine side of the specimens to the test fixture, while mechanical clamps were used to attach the placenta side. A FARO arm scanner recorded the initial geometry of the tissue, and a random dot pattern applied to the placenta and uterus tissue allowed visualization of displacement. For the structure of the UPI, mean tensile failure strain and standard deviations are 0.37 (0.11) and 0.37 (0.18) for the 0.10 and 1.0 strain rates, respectively (p-value = 0.970) while the associated failure stresses are 6.5 (1.37) and 15.0 (5.08) kPa, (p-value = 0.064). The results from sheep UPI testing provide the first estimate of the human UPI structural failure tolerance.
数据关于子宫胎盘界面（UPI）的强度将有助于提高对机动车碰撞中胎盘早剥（胎盘与子宫过早分离）机制的理解，而这些碰撞涉及到孕妇。选择绵羊模型进行研究是因为它的胎盘与人类胎盘一样，具有绒毛附着结构。从三只绵羊中获得了完整胎盘的子宫作为另一项研究的副产品。样本是在妊娠 145 天的 102 至 119 天之间收获的。通过胎盘和子宫的厚度切割出面积为 15mm×5mm 的矩形样本。每个研究对象提供 8 个样本，其中 4 个在名义应变速率为 0.10 应变/秒下进行测试，其余在名义应变速率为 1.0 应变/秒下进行测试。缝线用于将标本的子宫侧固定到测试夹具上，而机械夹具用于固定胎盘侧。FARO 臂扫描仪记录组织的初始几何形状，随机点图案应用于胎盘和子宫组织，以可视化位移。对于 UPI 的结构，在 0.10 和 1.0 应变速率下，平均拉伸失效应变和标准偏差分别为 0.37（0.11）和 0.37（0.18）（p 值=0.970），而相关失效应力分别为 6.5（1.37）和 15.0（5.08）kPa（p 值=0.064）。来自绵羊 UPI 测试的结果提供了人类 UPI 结构失效容限的首次估计。
