Fick J M, Ronkainen A, Herzog W, Korhonen R K
Department of Applied Physics, University of Eastern Finland, Yliopistonranta 1, Kuopio FI-70211, Finland.
Department of Applied Physics, University of Eastern Finland, Yliopistonranta 1, Kuopio FI-70211, Finland.
J Biomech. 2015 Nov 26;48(15):4010-4019. doi: 10.1016/j.jbiomech.2015.09.049. Epub 2015 Oct 23.
Biomechanical responses of chondrocytes were determined in specific locations within the superficial zone of patellar, femoral groove, femoral condyle and tibial plateau cartilages obtained from female New Zealand White rabbits. A confocal laser scanning microscope combined with a custom indentation system was utilized for experimentation. Changes in cell volumes and dimensions (i.e. cell height, width and depth) due to loading, global, local axial and transverse strains were determined for each site. Tissue composition and structure was analysed at each indentation site with digital densitometry, polarized light microscopy and Fourier transform infrared imaging spectroscopy. Patellar cells underwent greater volume decreases (compared to femoral groove cells; p<0.05) primarily due to greater decreases in cell height (p<0.05), consistent with greater levels of both global and local axial strains (p<0.05). Lateral condyle cells underwent greater volume decreases (compared to lateral plateau cells; p<0.05) primarily due to greater decreases in cell height, consistent with greater levels of tissue strains (p<0.05). Medial condyle cells underwent smaller volume decreases (compared to medial plateau cells; p<0.05) primarily due to elevated cell expansions in the depth direction, which was consistent with greater levels of minor transverse strains (p<0.05). Site-dependent differences in collagen orientation angles agreed conceptually with the observed cell dimensional changes. Chondrocyte biomechanical responses were highly site-dependent and corresponded primarily with the orientation of the collagen fibrils. The observed differences were thought to be due to the different biomechanical loading conditions at each site.
在从雌性新西兰白兔获取的髌软骨、股骨髁间沟、股骨髁和胫骨平台软骨表层特定位置测定软骨细胞的生物力学反应。使用共聚焦激光扫描显微镜结合定制压痕系统进行实验。确定每个部位因加载、整体、局部轴向和横向应变导致的细胞体积和尺寸（即细胞高度、宽度和深度）变化。在每个压痕部位用数字密度测定法、偏振光显微镜和傅里叶变换红外成像光谱分析组织组成和结构。髌软骨细胞体积减小幅度更大（与股骨髁间沟细胞相比；p<0.05），主要是由于细胞高度减小幅度更大（p<0.05），这与整体和局部轴向应变水平更高一致（p<0.05）。外侧髁软骨细胞体积减小幅度更大（与外侧平台软骨细胞相比；p<0.05），主要是由于细胞高度减小幅度更大，这与组织应变水平更高一致（p<0.05）。内侧髁软骨细胞体积减小幅度较小（与内侧平台软骨细胞相比；p<0.05），主要是由于细胞在深度方向的扩张增加，这与较小横向应变水平更高一致（p<0.05）。胶原取向角的部位依赖性差异在概念上与观察到的细胞尺寸变化一致。软骨细胞的生物力学反应高度依赖部位，且主要与胶原纤维的取向相对应。观察到的差异被认为是由于每个部位不同的生物力学加载条件所致。
