Gao Jenny, Martin Lucia, Loffet Elise A, Durel John F, Oikonomou Panagiotis, Nerurkar Nandan L
Department of Biomedical Engineering, Columbia University, New York NY 10027.
bioRxiv. 2024 Aug 9:2024.08.07.606927. doi: 10.1101/2024.08.07.606927.
During embryonic development, tissues undergo dramatic deformations as functional morphologies are stereotypically sculpted from simple rudiments. Formation of healthy, functional organs therefore requires tight control over the material properties of embryonic tissues during development, yet the biological basis of embryonic tissue mechanics is poorly understood. The present study investigates the mechanics of the embryonic small intestine, a tissue that is compactly organized in the body cavity by a mechanical instability during development, wherein differential elongation rates between the intestinal tube and its attached mesentery create compressive forces that buckle the tube into loops with wavelength and curvature that are tightly conserved for a given species. Focusing on the intestinal tube, we combined micromechanical testing with histologic analyses and enzymatic degradation experiments to conclude that elastic fibers closely associated with intestinal smooth muscle layers are responsible for the bending stiffness of the tube, and for establishing its pronounced mechanical anisotropy. These findings provide insights into the developmental role of elastic fibers in controlling tissue stiffness, and raise new questions on the physiologic function of elastic fibers in the intestine during adulthood.
在胚胎发育过程中，随着功能形态从简单的原基中刻板地塑造出来，组织会经历剧烈的变形。因此，健康、功能正常的器官形成需要在发育过程中严格控制胚胎组织的材料特性，然而，胚胎组织力学的生物学基础却知之甚少。本研究调查了胚胎小肠的力学特性，小肠组织在发育过程中通过一种机械不稳定性在体腔内紧密组织起来，其中肠管与其附着的肠系膜之间的差异伸长率产生压缩力，使肠管弯曲成环，其波长和曲率对于给定物种来说是严格保守的。聚焦于肠管，我们将微观力学测试与组织学分析及酶降解实验相结合，得出结论：与肠平滑肌层紧密相关的弹性纤维负责肠管的弯曲刚度，并建立其明显的机械各向异性。这些发现为弹性纤维在控制组织刚度方面的发育作用提供了见解，并对成年期弹性纤维在肠道中的生理功能提出了新问题。
