Bursać P, McGrath C V, Eisenberg S R, Stamenović D
Department of Biomedical Engineering, Boston University, MA 02215, USA.
J Biomech Eng. 2000 Aug;122(4):347-53. doi: 10.1115/1.1286561.
A microstructural model of cartilage was developed to investigate the relative contribution of tissue matrix components to its elastostatic properties. Cartilage was depicted as a tensed collagen lattice pressurized by the Donnan osmotic swelling pressure of proteoglycans. As a first step in modeling the collagen lattice, two-dimensional networks of tensed, elastic, interconnected cables were studied as conceptual models. The models were subjected to the boundary conditions of confined compression and stress-strain curves and elastic moduli were obtained as a function of a two-dimensional equivalent of swelling pressure. Model predictions were compared to equilibrium confined compression moduli of calf cartilage obtained at different bath concentrations ranging from 0.01 to 0.50 M NaCl. It was found that a triangular cable network provided the most consistent correspondence to the experimental data. The model showed that the cartilage collagen network remained tensed under large confined compression strains and could therefore support shear stress. The model also predicted that the elastic moduli increased with increasing swelling pressure in a manner qualitatively similar to experimental observations. Although the model did not preclude potential contributions of other tissue components and mechanisms, the consistency of model predictions with experimental observations suggests that the cartilage collagen network, prestressed by proteoglycan swelling pressure, plays an important role in supporting compression.
为研究组织基质成分对软骨弹性静力学特性的相对贡献，建立了软骨微观结构模型。软骨被描述为一个由蛋白聚糖的唐南渗透压肿胀压力加压的张紧胶原晶格。作为对胶原晶格建模的第一步，研究了张紧的、弹性的、相互连接的缆线的二维网络作为概念模型。对这些模型施加受限压缩的边界条件并获得应力-应变曲线，弹性模量作为二维等效肿胀压力的函数得到。将模型预测结果与在0.01至0.50 M NaCl不同浴浓度下获得的小牛软骨平衡受限压缩模量进行比较。发现三角形缆线网络与实验数据的对应最为一致。该模型表明，软骨胶原网络在大的受限压缩应变下仍保持张紧，因此能够承受剪应力。该模型还预测，弹性模量随肿胀压力增加而增加，其方式在定性上与实验观察结果相似。虽然该模型并不排除其他组织成分和机制的潜在贡献，但模型预测与实验观察结果的一致性表明，由蛋白聚糖肿胀压力预加应力的软骨胶原网络在支撑压缩方面起着重要作用。
