Duncan Neil A
Schulich School of Engineering, University of Calgary, 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canada.
J Bone Joint Surg Am. 2006 Apr;88 Suppl 2:47-51. doi: 10.2106/JBJS.F.00035.
The purpose of this research was to explore the in situ anatomic and mechanical environment of disc cells. Laser scanning confocal microscopy was used to characterize three-dimensional morphology of intervertebral disc cells, micromechanical deformation and interaction with extracellular matrix, and functional intercellular communication. Bovine coccygeal discs were used for both the anatomic and micromechanical investigations. Anulus fibrosus cells had a complex morphology with sinuous processes woven into the extracellular matrix, particularly in the outer aspect of the anulus where they were also interconnected via functional gap junctions. They were also found in an extensive pericellular matrix of type-VI collagen, joining as many as ten cells into linear cell arrays that could be extracted from the matrix as functional units. Mechanically, collagen fibril sliding was demonstrated to govern cell mechanics and strain transfer in the anulus fibrosus during loading activities. Lamellar cells were largely protected from direct tensile strains in the matrix, with minimal intercellular strains. However, intercellular strains between lamellar cells in adjacent arrays were large, illustrating shearing between linear cell arrays. Appreciable shear was observed across the lamellar cell bodies as well as to the cellular processes woven into the matrix. These findings demonstrated the morphologic and micromechanical complexity of anulus fibrosus cells. The knowledge of the in situ environment of disc cells will provide a base to investigate the mechanical implications of disc degeneration on the cellular environment and to better understand how mechanical and genetic risk factors can impact the cells that are essential to maintaining the intervertebral disc.
本研究的目的是探索椎间盘细胞的原位解剖学和力学环境。利用激光扫描共聚焦显微镜来表征椎间盘细胞的三维形态、微机械变形以及与细胞外基质的相互作用，还有功能性细胞间通讯。牛尾椎间盘用于解剖学和微机械研究。纤维环细胞具有复杂的形态，其蜿蜒的突起交织在细胞外基质中，尤其是在纤维环的外侧，它们还通过功能性缝隙连接相互连接。它们还存在于广泛的VI型胶原细胞周基质中，多达十个细胞连接成线性细胞阵列，这些阵列可作为功能单元从基质中提取出来。在力学方面，已证明胶原纤维滑动在加载活动期间控制纤维环中的细胞力学和应变传递。板层细胞在很大程度上免受基质中的直接拉伸应变影响，细胞间应变最小。然而，相邻阵列中板层细胞之间的细胞间应变很大，这说明了线性细胞阵列之间的剪切作用。在板层细胞体以及编织到基质中的细胞突起上都观察到了明显的剪切力。这些发现证明了纤维环细胞的形态学和微机械复杂性。了解椎间盘细胞的原位环境将为研究椎间盘退变对细胞环境的力学影响以及更好地理解机械和遗传风险因素如何影响维持椎间盘所必需的细胞提供基础。
