Characterization of articular cartilage by combining microscopic analysis with a fibril-reinforced finite-element model
Characterization of articular cartilage by combining microscopic analysis with a fibril-reinforced finite-element model
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DOI：
10.1016/j.jbiomech.2006.07.026
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发表时间：
2007-01-01
影响因子：
2.4
通讯作者：
Korhonen, Rarni K.
中科院分区：
文献类型：
--
作者：
Julkunen, Petro;Kiviranta, Panu;Korhonen, Rarni K.
关节软骨的承重特性在组织变性过程中受损。定量显微镜能够在体外研究软骨结构，但组织功能特性的测定需要实验力学测试。纤维增强孔粘弹性（FRPVE）模型已成功用于软骨力学性能的估计。该模型包括真实的胶原蛋白网络结构，如显微镜成像技术所示。本研究的目的是研究软骨蛋白多糖（PG）和胶原蛋白含量之间的关系，通过定量显微镜观察结果和基于模型的组织力学参数进行评估。分析了胶原网络模量、PG基质模量和通透性的位点特异性变化。圆柱形软骨样本（n = 22）从牛膝关节和肩关节的不同部位收获。通过偏振光显微镜定量测定胶原蛋白取向，并将其纳入有限元模型。对试样进行无侧限压缩逐步应力松弛实验，并对实验数据拟合试样模型，确定模型参数值。为了比较，傅里叶变换红外成像和数字密度仪分别用于测定同一样品中的胶原蛋白和PG含量。初始和应变依赖性纤维网络模量以及初始通透性与组织胶原含量显著相关。非纤维基质的平衡杨氏模量和渗透性的应变依赖关系与组织PG含量显著相关。本研究表明，现代定量显微方法结合FRPVE模型是表征关节软骨结构-功能关系的可行方法。(C) 2006 Elsevier Ltd版权所有。
Load-bearing characteristics of articular cartilage are impaired during tissue degeneration. Quantitative microscopy enables in vitro investigation of cartilage structure but determination of tissue functional properties necessitates experimental mechanical testing. The fibril-reinforced poroviscoelastic (FRPVE) model has been used successfully for estimation of cartilage mechanical properties. The model includes realistic collagen network architecture, as shown by microscopic imaging techniques. The aim of the present study was to investigate the relationships between the cartilage proteoglycan (PG) and collagen content as assessed by quantitative microscopic findings, and model-based mechanical parameters of the tissue. Site-specific variation of the collagen network moduli, PG matrix modulus and permeability was analyzed. Cylindrical cartilage samples (n = 22) were harvested from various sites of the bovine knee and shoulder joints. Collagen orientation, as quantitated by polarized light microscopy, was incorporated into the finite-element model. Stepwise stress-relaxation experiments in unconfined compression were conducted for the samples, and sample-specific models were fitted to the experimental data in order to determine values of the model parameters. For comparison, Fourier transform infrared imaging and digital densitometry were used for the determination of collagen and PG content in the same samples, respectively. The initial and strain-dependent fibril network moduli as well as the initial permeability correlated significantly with the tissue collagen content. The equilibrium Young's modulus of the nonfibrillar matrix and the strain dependency of permeability were significantly associated with the tissue PG content. The present study demonstrates that modern quantitative microscopic methods in combination with the FRPVE model are feasible methods to characterize the structure-function relationships of articular cartilage. (C) 2006 Elsevier Ltd. All rights reserved.