Xing Yuan, Zhang Pu, Zhang Yangpu, Holzer Liam, Xiao Li, He Yi, Majumdar Rahul, Huo Jianzhong, Yu Xiaoyu, Ramasubramanian Melur K, Jin Li, Wang Yong, Li Xudong, Oberholzer Jose
Department of Surgery, University of Virginia, 345 Crispell Drive, Charlottesville, VA, 22908, United States.
Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer's Way, Charlottesville, VA, 22904, United States.
J Mech Behav Biomed Mater. 2020 May;105:103636. doi: 10.1016/j.jmbbm.2020.103636. Epub 2020 Jan 20.
Mechanical loading plays an important role in maintaining disc health and function, and in particular, excessive mechanical loading has been identified as one of major reasons of disc degeneration. Intervertebral disc organ culture serves as a valuable tool to study disc biology/pathology. In this study, we report the development and validation of a new mouse disc organ culture system by dynamically applying compression loading in a customized micro-culture device tailored for mouse lumbar discs. Precise axial compression force was delivered by a computer-controlled system consisting of a robust micromechanical linear actuator, a force sensitive resistor, and a precision micro-stepping machinery. Customized PDMS-based loading chambers allowed simultaneous loading of six discs per regimen, which streamlined the workflow to reach sufficient statistic power. The detrimental loading regimen of mouse lumbar discs (0.5 MPa of axial compression at 1Hz for 7 days) was demonstrated through live-dead assay, histology, and fluorescence probe based collagen staining. In addition, various mechanical compression profiles were simulated using different materials and geometry designs, potentiating for more sophisticated loading protocols. In summary, we developed a new mechanical loading system for dynamic axial compression of mouse discs, which created a unique avenue to study disc pathogenesis with enriched mouse species-related resources, and complemented the existing spectrum of bioreactor systems predominately for discs of human and large animals.
机械负荷在维持椎间盘的健康和功能方面起着重要作用，尤其是过度的机械负荷已被确认为椎间盘退变的主要原因之一。椎间盘器官培养是研究椎间盘生物学/病理学的一种有价值的工具。在本研究中，我们报告了一种新的小鼠椎间盘器官培养系统的开发和验证，该系统通过在为小鼠腰椎间盘量身定制的微型培养装置中动态施加压缩负荷来实现。精确的轴向压缩力由一个计算机控制系统提供，该系统由一个坚固的微机械线性致动器、一个力敏电阻器和一个精密微步机械组成。定制的基于聚二甲基硅氧烷（PDMS）的加载室允许每个方案同时加载六个椎间盘，这简化了工作流程以获得足够的统计效力。通过活死检测、组织学和基于荧光探针的胶原蛋白染色，证实了小鼠腰椎间盘的有害负荷方案（1Hz频率下0.5MPa轴向压缩，持续7天）。此外，使用不同的材料和几何设计模拟了各种机械压缩曲线，为更复杂的加载方案提供了可能。总之，我们开发了一种用于小鼠椎间盘动态轴向压缩的新型机械加载系统，该系统为利用丰富的小鼠物种相关资源研究椎间盘发病机制开辟了一条独特的途径，并补充了现有的主要用于人类和大型动物椎间盘的生物反应器系统。
