Wilkes R P, Athanasiou K A
Orthopedic Biomechanics Laboratory, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78284-7774.
Tissue Eng. 1996 Fall;2(3):167-81. doi: 10.1089/ten.1996.2.167.
This paper presents a new methodology, apparatus design, and the experimental results of ongoing research into the measurement of the mechanical properties of musculoskeletal tissue at the cellular level. A microchamber was constructed that provides a controlled hydrostatic pressure environment for these cells where optical sectioning, via epifluorescence microscopy, was used to acquire volume information about the individual cell. The microchamber was integrated into a hydraulic system that, via computer control, provided a regulated adjustable hydrostatic pressure environment for living cells suspended in culture media. The techniques applied in this study include fluorescent labeling of the cell volume, hydrostatic pressure application, optical sectioning, and digital volume reconstruction. To determine the mechanical response (compressibility) of cultured MG-63 osteoblast-like cells under physiologically high hydrostatic pressures two experiments were devised: In the first experiment changes in volume of 10 cells were measured as the applied hydrostatic pressure was increased from 0 to 7 MPa. Volume changes in response to pressure magnitudes were not significant (p > 0.49). In the second experiment, the mechanical role of the plasma membrane to act as a supportive component in cell compressibility was studied by permeabilizing the membrane of six cells and again applying hydrostatic pressure. Again, no significant volume differences between pressurized and unpressurized cells were found (p > 0.46). A retrospective power analysis of the results of the first and second experiments indicates that the sample size was sufficient. The results of this study show that MG-63 osteoblast-like cells are intrinsically incompressible in the 0-7 MPa hydrostatic pressure range. They also support the hypothesis that the plasma membrane plays an insignificant mechanical role in terms of cell compressibility.
本文介绍了一种新方法、仪器设计以及正在进行的关于在细胞水平测量肌肉骨骼组织力学性能研究的实验结果。构建了一个微腔室，为这些细胞提供可控的静水压力环境，通过落射荧光显微镜进行光学切片，用于获取单个细胞的体积信息。该微腔室集成到一个液压系统中，通过计算机控制，为悬浮在培养基中的活细胞提供一个可调节的稳定静水压力环境。本研究应用的技术包括细胞体积的荧光标记、静水压力施加、光学切片和数字体积重建。为了确定在生理高静水压力下培养的MG - 63成骨样细胞的力学响应（压缩性），设计了两个实验：在第一个实验中，当施加的静水压力从0增加到7 MPa时，测量10个细胞的体积变化。压力变化引起的体积变化不显著（p>0.49）。在第二个实验中，通过使六个细胞的膜通透并再次施加静水压力，研究了质膜在细胞压缩性中作为支撑成分的力学作用。同样，加压细胞和未加压细胞之间未发现显著的体积差异（p>0.46）。对第一个和第二个实验结果的回顾性功效分析表明样本量足够。本研究结果表明，在0 - 7 MPa静水压力范围内，MG - 63成骨样细胞本质上是不可压缩的。它们还支持这样的假设，即质膜在细胞压缩性方面的力学作用不显著。
