Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
Tissue Eng Part A. 2013 Jul;19(13-14):1621-31. doi: 10.1089/ten.TEA.2012.0541. Epub 2013 Apr 10.
The mechanical properties of articular cartilage are dominated by the interterritorial matrix, as the matrix in this region is stiffer, greater in volume, and more interconnected compared to that in the pericellular and territorial region. Hence, tissue-engineered constructs in which a newly synthesized matrix accumulates in the pericellular and territorial regions may be of a lower mechanical quality compared to constructs in which the interterritorial region contains abundant matrix.
In this study, we explored the extent to which matrix distribution may be modulated by altering the agarose concentration and the presence of the transforming growth factor-β (TGF-β) and how this affects the mechanical properties of cultured cartilage constructs.
Cartilage development in constructs with agarose concentrations varying from 1%, 2%, and 3% (study 1) and in constructs with no or very low agarose concentrations of 0.25%, 0.5%, and 1% (study 2) were compared. In both studies, the effect of TGF-β3 was compared to fetal bovine serum. After 21 and 42 days of culture, the matrix content and distribution were analyzed and mechanical properties were assessed at day 42.
Culture in lower agarose concentrations did not significantly influence the matrix content per wet weight, but did result in a more homogeneous distribution. Constructs cultured with less agarose also showed a higher equilibrium modulus. The presence of TGF-β3 resulted in an increased extracellular matrix (ECM) deposition, a more homogeneous matrix distribution, and an equilibrium modulus.
Culturing with no or low agarose concentrations and TGF-β3 is favorable for cartilage tissue-engineering studies, because both stimulate the formation of a more homogeneous ECM and consequently result in improved mechanical properties.
关节软骨的力学性能主要由细胞外基质决定，因为细胞外基质在细胞间区域的硬度更高、体积更大且更相互连接。因此，与细胞间区域含有丰富基质的组织工程构建体相比，新合成的基质在细胞周和组织区域积累的构建体的机械质量可能较低。
本研究旨在探讨通过改变琼脂糖浓度以及转化生长因子-β（TGF-β）的存在来调节基质分布的程度，以及这如何影响培养的软骨构建体的机械性能。
比较了琼脂糖浓度分别为 1%、2%和 3%的构建体（研究 1）和琼脂糖浓度分别为 0.25%、0.5%和 1%的构建体（研究 2）中软骨的发育情况。在这两项研究中，均比较了 TGF-β3 与胎牛血清的作用。培养 21 天和 42 天后，分析基质含量和分布，然后在第 42 天评估力学性能。
在较低琼脂糖浓度下培养不会显著影响每湿重的基质含量，但会导致更均匀的分布。用较少琼脂糖培养的构建体也显示出更高的平衡模量。TGF-β3 的存在会导致细胞外基质（ECM）沉积增加、基质分布更均匀以及平衡模量增加。
无琼脂糖或低琼脂糖浓度以及 TGF-β3 的培养有利于软骨组织工程研究，因为这两者都能刺激形成更均匀的 ECM，从而导致机械性能得到改善。
