Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
Department of Applied Physics, University of Eastern Finland, Kuopio, Finland; Turku Bioscience Centre, University of Turku, Turku and Åbo Akademi University, Turku, Finland.
J Biomech. 2020 Mar 5;101:109648. doi: 10.1016/j.jbiomech.2020.109648. Epub 2020 Jan 17.
Characterization of the mechanical environment of cells in collagenous biological tissues during different daily activities is crucial for understanding the role of mechanics on cell biosynthesis and tissue health. However, current imaging methods are limited in characterizing very fast deformations of cells. This could be achieved with computational multiscale modeling, but current models accommodating collagen fibril networks and poroelastic ground matrix have included only a single cell. In this study, a workflow was developed for generating a three-dimensional multiscale model with imaging-based anatomical cell distributions and their micro-environment (pericellular and extracellular matrix). Fibril-reinforced poroelastic material models with (FRPES) and without (FRPE) swelling were implemented into the model and simulations were performed for evaluating cell deformations before and after experimental loading conducted for rabbit knee joint cartilage. We observed that the cells experienced considerably different deformation based on their location in all models. Both FRPE and FRPES models were able to predict the trends in the changes in cell deformations, although the average and median magnitudes differed between the model predictions and experiments. However, the FRPES model results were generally closer to the experimental results. Current findings suggest that morphological properties of cells are affected by the variations in the tissue properties between the samples and variations within the sample caused by the measurement geometry, local structure and composition. Thus, it would be important to consider the anatomical distribution and location of multiple cells along with the structure of fibril networks if cell deformation metrics are evaluated in collagenous tissues.
描述胶原质生物组织中细胞在不同日常活动下的力学环境对于理解力学对细胞生物合成和组织健康的作用至关重要。然而，目前的成像方法在描述细胞的快速变形方面存在局限性。这可以通过计算多尺度建模来实现，但目前的模型容纳胶原纤维网络和多孔弹性基质的模型仅包含单个细胞。在这项研究中，开发了一种工作流程，用于生成具有基于成像的解剖细胞分布及其微环境（细胞周和细胞外基质）的三维多尺度模型。将纤维增强多孔弹性材料模型（FRPES）和无膨胀（FRPE）纳入模型中，并对兔膝关节软骨进行实验加载前后的细胞变形进行模拟。我们观察到，根据所有模型中细胞的位置，细胞经历了相当不同的变形。尽管模型预测和实验之间存在平均和中位数差异，但 FRPE 和 FRPES 模型都能够预测细胞变形变化的趋势。然而，FRPES 模型的结果通常更接近实验结果。目前的研究结果表明，细胞的形态特性受到组织性质在样本之间的变化以及测量几何形状、局部结构和组成引起的样本内变化的影响。因此，如果要评估胶原质组织中的细胞变形度量，那么考虑多个细胞的解剖分布和位置以及纤维网络的结构非常重要。
