Allen Daniel M, Mao Jeremy J
Tissue Engineering Laboratory Rm 237, Departments of Bioengineering and Orthodontics (MC 841), University of Illinois at Chicago, 801 South Paulina Street, Chicago, IL 60612-7211, USA.
J Struct Biol. 2004 Mar;145(3):196-204. doi: 10.1016/j.jsb.2003.10.003.
Hyaline cartilage consists of sparse chondrocytes and abundant extracellular matrix. There is a paucity of experimental data in support of the notion of conceivable regional differences in the mechanical properties of chondral matrices. Upon visual differentiation of the pericellular and interterritorial matrices in each of 19 fresh growth plate samples with toluidine blue and alizarin red labels, nanoindentation was applied separately to the pericellular matrix and interterritorial matrix to using fluid-phase atomic force microscopy and real-time imaging. The interterritorial matrix demonstrated elongated parallel ridges, whereas the pericellular matrix showed irregular, short-range elevations with characteristic pores and canals. Analysis of surface contours at 600nm(2) scan size revealed that the interterritorial matrix had significantly greater surface roughness (71+/-18nm; mean+/-SE) than the pericellular matrix (24+/-4nm) ( P< 0.001). The average Young's modulus of the interterritorial matrix was 636+/-123 (kPa), significantly greater than the pericellular matrix (265+/-53kPa) (P< 0.001 ). Thus, the interterritorial matrix appears to possess not only distinct microtopographic contours in comparison with the pericellular matrix, but also significantly greater mechanical stiffness. These distinctive nanostructural and nanomechanical properties may have implications in nutrient diffusion and fluid dynamics, both of which are of vital importance for cartilage health and function.
透明软骨由稀疏的软骨细胞和丰富的细胞外基质组成。关于软骨基质力学性能可能存在区域差异这一观点，目前缺乏实验数据支持。在对19个新鲜生长板样本分别用甲苯胺蓝和茜素红标记以视觉区分细胞周围基质和细胞间基质后，使用液相原子力显微镜和实时成像技术分别对细胞周围基质和细胞间基质进行纳米压痕测试。细胞间基质呈现出细长的平行脊状结构，而细胞周围基质则显示出不规则的、短程的隆起，并带有特征性的孔隙和管道。在600nm(2)扫描尺寸下对表面轮廓进行分析发现，细胞间基质的表面粗糙度（71±18nm；平均值±标准误）显著高于细胞周围基质（24±4nm）（P<0.001）。细胞间基质的平均杨氏模量为636±123（kPa），显著高于细胞周围基质（265±53kPa）（P<0.001）。因此，细胞间基质不仅与细胞周围基质相比具有明显不同的微观形貌轮廓，而且具有显著更高的机械刚度。这些独特的纳米结构和纳米力学特性可能对营养物质扩散和流体动力学产生影响，而这两者对软骨的健康和功能都至关重要。
