软骨细胞力学环境的跨尺度计算

目的通过跨尺度计算,比较表层和深层软骨细胞的周边力学环境。方法建立软骨细胞两相力学模型,将软骨两相力学模型里的结果映射到细胞模型对应边界上作为边界条件。计算细胞模型得到软骨细胞的周边力学环境并进行分析。结果深层软骨细胞及周边应力比表层细胞的小一半,但都远小于细胞外的应力。软骨细胞周围基质(pericellular matrix,PCM)承担了细胞外的高应力,显著降低了细胞内的应力。两处细胞周围的间隙流动方向完全相反。结论软骨承载能力使深层软骨细胞附近应力显著降低,保护了深层软骨细胞及软骨下骨。PCM承担了细胞外围高应力,保证了软骨细胞生存工作所需的低应力环境。两处细胞周围相反的间隙流动支持了由表层关节液渗透及软骨下骨营养泵入构成的软骨双向营养供给学说。

Multiscale computation on mechanical environment of chondrocytes

Objective To compare the mechanical environment of chondrocytes between superficial zone and deep zone by multiscale computation. Methods The chondrocyte biphasic model was set up and made the results of the articular cartilage (AC) biphasic model mapped to the corresponding borders of the chondrocyte model as the boundary condition. The chondrocyte model was computed to obtain the results of the mechanical environment of chondrocytes and analyzed. Results The results showed that the stress of chondrocytes at deep zone was half of that at superficial zone, but both were much smaller than those outside chondrocytes. The pericellular matrix (PCM) sustained the high stress outside chondrocytes and remarkably reduced the stress inside chondrocytes. Interstitial flow directions adjacent to two chondrocytes were totally the opposite.Conclusions The bearing property of AC reduced the stress near chondrocytes at deep zone prominently and protected the chondrocytes at deep zone and subchondral bone. PCM sustained the high stress outside chondrocytes to provide lower stress environment for chondrocytes living. The opposite interstitial flow direction of two chondrocytes supported the theory that synovia seepage from cartilage surface and nutrient pumped out from subchondral bone constitute the bidirectional nutrient supply in AC.