Damon Brooke J, Rémond Mathieu C, Bigelow Michael R, Trusk Thomas C, Xie Wenjie, Perucchio Renato, Sedmera David, Denslow Stewart, Thompson Robert P
Department of Cell Biology and Anatomy, Medical University of South Carolina, Charleston, South Carolina, USA.
Dev Dyn. 2009 Jun;238(6):1535-46. doi: 10.1002/dvdy.21958.
The hypothesis that inner layers of contracting muscular tubes undergo greater strain than concentric outer layers was tested by numerical modeling and by confocal microscopy of strain within the wall of the early chick heart. We modeled the looped heart as a thin muscular shell surrounding an inner layer of sponge-like trabeculae by two methods: calculation within a two-dimensional three-variable lumped model and simulated expansion of a three-dimensional, four-layer mesh of finite elements. Analysis of both models, and correlative microscopy of chamber dimensions, sarcomere spacing, and membrane leaks, indicate a gradient of strain decreasing across the wall from highest strain along inner layers. Prediction of wall thickening during expansion was confirmed by ultrasonography of beating hearts. Degree of stretch determined by radial position may thus contribute to observed patterns of regional myocardial conditioning and slowed proliferation, as well as to the morphogenesis of ventricular trabeculae and conduction fascicles. Developmental Dynamics 238:1535-1546, 2009. (c) 2009 Wiley-Liss, Inc.
通过数值模拟和早期鸡胚心脏壁内应变的共聚焦显微镜观察，对收缩性肌管内层比同心外层承受更大应变这一假说进行了验证。我们采用两种方法将环状心脏模拟为围绕海绵状小梁内层的薄肌壳：在二维三变量集总模型内进行计算，以及对三维四层有限元网格进行模拟扩展。对这两种模型的分析，以及对腔室尺寸、肌节间距和膜渗漏的相关显微镜观察，均表明应变梯度从内层的最高应变开始沿壁递减。跳动心脏的超声检查证实了扩张过程中壁增厚的预测。因此，由径向位置决定的伸展程度可能有助于解释观察到的区域心肌调节模式和增殖减缓现象，以及心室小梁和传导束的形态发生。《发育动力学》238:1535 - 1546，2009年。(c) 2009威利 - 利斯出版公司。
