National Taiwan University Hospital, Taipei, Taiwan.
Tissue Eng Part A. 2011 Dec;17(23-24):2919-29. doi: 10.1089/ten.tea.2010.0732. Epub 2011 Sep 6.
Implantation of autologous chondrogenic cells has become the mainstay strategy for repairing articular cartilage defects. Because the availability of autologous chondrocytes is extremely limited, many recent studies have used artificially induced mesenchymal stem cells (iMSCs) as substitutes for chondrocytes. In this study, we analyzed the differences between the iMSCs and chondrocytes, including their molecular biological and mechanical properties. Human bone marrow-derived MSCs were collected and induced to exhibit the chondrogenic phenotype by culturing the pelleted MSCs in a chemically defined culture medium supplemented with transforming growth factor-beta 1. The molecular biological properties of iMSCs and culture-expanded chondrocytes, including their mRNA profiles and surface proteomics, were analyzed using reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometry, respectively. The biomechanical properties of iMSCs and native chondrocytes, including their surface topology, adhesion force, and membrane stiffness, were analyzed using atomic force microscopy (AFM). Both iMSCs and chondrocytes presented type II collagen and glycosaminoglycan, whereas only chondrocytes presented type X collagen. Flow cytometric assays showed that the expression of type II collagen and integrin-1 was higher in the chondrocytes than in the iMSCs. AFM revealed that the MSCs, iMSCs, and chondrocytes greatly differed in their shape. The MSCs were spindle shaped and easily distinguishable from the spherical chondrocytes. The iMSCs appeared round and resembled the spherical chondrocytes; however, the iMSCs were flatter with a central hump of condensed mass and a surrounding thin and broad pleat. The mean adhesion force and mean surface stiffness were significantly lower for the iMSCs (4.54 nN and 0.109 N/m, respectively) than for the chondrocytes (6.86 nN and 0.134 N/m, respectively). To conclude, although the iMSCs exhibited the chondrogenic phenotype, they differed from the chondrocytes in their molecular biological and mechanical properties.
自体软骨细胞的植入已成为修复关节软骨缺损的主要策略。由于自体软骨细胞的可用性极其有限，许多最近的研究使用人工诱导的间充质干细胞（iMSCs）作为软骨细胞的替代品。在这项研究中，我们分析了 iMSCs 和软骨细胞之间的差异，包括它们的分子生物学和力学特性。我们从人骨髓中分离出间充质干细胞，通过在含有转化生长因子-β1 的化学定义培养基中培养细胞团块来诱导其表现出软骨细胞表型。使用逆转录聚合酶链反应（RT-PCR）和流式细胞术分别分析 iMSCs 和培养扩增的软骨细胞的分子生物学特性，包括它们的 mRNA 谱和表面蛋白质组学。使用原子力显微镜（AFM）分析 iMSCs 和天然软骨细胞的生物力学特性，包括它们的表面拓扑结构、黏附力和膜硬度。iMSCs 和软骨细胞均呈现 II 型胶原和糖胺聚糖，而只有软骨细胞呈现 X 型胶原。流式细胞术检测表明，软骨细胞中 II 型胶原和整合素-1 的表达高于 iMSCs。AFM 显示，MSC、iMSCs 和软骨细胞在形状上有很大差异。MSC 呈纺锤形，与球形软骨细胞容易区分。iMSCs 呈圆形，类似于球形软骨细胞；然而，iMSCs 更平坦，中间有一个凝聚物质的凸起，周围有一个薄而宽的褶皱。iMSCs 的平均黏附力和平均表面硬度分别显著低于软骨细胞（分别为 4.54 nN 和 0.109 N/m）。总之，尽管 iMSCs 表现出软骨细胞表型，但它们在分子生物学和力学特性方面与软骨细胞不同。
