Tomkoria Sara, Patel Rupal V, Mao Jeremy J
Tissue Engineering Laboratory, Department of Orthodontics, University of Illinois at Chicago, Room 237, 801 South Paulina Street, MC 841, Chicago, IL 60612-7211, USA.
Med Eng Phys. 2004 Dec;26(10):815-22. doi: 10.1016/j.medengphy.2004.07.006.
Articular chondrocytes have been thought to reside in a homogenous matrix. The physical characteristics of the intercellular matrix of articular cartilage are not well characterized, especially at a nanoscopic scale. The present work tested the hypothesis that the nanomechanical properties of the intercellular matrices of articular cartilage in both the articulating surface and various cellular zones are non-homogeneous. Nanoindentation by atomic force microscopy was applied to the geometric center of the medial, lateral and groove regions of the superficial zone of the rabbit proximal radius cartilage, and then the intercellular matrices of chondrocytes from the superficial to calcifying zones in 40 microm increments. The elastic modulus of the articular surface of the medial condyle (1.46+/-0.11 MPa) was significantly higher than the lateral condyle (1.18+/-0.10 MPa), and the groove (0.96+/-0.07 MPa). There is a significant gradient increase in Young's moduli from the superficial zone (0.52+/-0.05 MPa) to calcifying zone (1.69+/-0.12 MPa). Thus, the nanomechanical properties of the intercellular matrices of the articulating surface are region-specific and likely related to articular function. Heterogeneous biophysical properties of intercellular matrices along the depth from the superficial to calcifying zones suggest that chondrocytes likely reside in a heterogeneous matrix.
关节软骨细胞一直被认为存在于均质的基质中。关节软骨细胞间基质的物理特性尚未得到很好的表征，尤其是在纳米尺度上。本研究检验了以下假设：关节软骨关节表面和不同细胞区域的细胞间基质的纳米力学特性是不均匀的。利用原子力显微镜对兔桡骨近端软骨表层区域的内侧、外侧和沟区域的几何中心进行纳米压痕测试，然后以40微米的增量对从表层到钙化层的软骨细胞的细胞间基质进行测试。内侧髁关节表面的弹性模量（1.46±0.11兆帕）显著高于外侧髁（1.18±0.,10兆帕）和沟（0.96±0.07兆帕）。从表层区域（0.52±0.05兆帕）到钙化区域（1.69±0.12兆帕），杨氏模量有显著的梯度增加。因此，关节表面细胞间基质的纳米力学特性具有区域特异性，并且可能与关节功能有关。从表层到钙化层深度方向上细胞间基质的异质生物物理特性表明，软骨细胞可能存在于异质基质中。
