Department of Orthopedics, First Affiliated Hospital, Nanjing Medical University, Jiangsu, China.
Braz J Med Biol Res. 2011 Apr;44(4):303-10. doi: 10.1590/s0100-879x2011007500026. Epub 2011 Mar 4.
Chondrocytes and bone marrow mesenchymal stem cells (BMSCs) are frequently used as seed cells in cartilage tissue engineering. In the present study, we determined if the co-culture of rabbit articular chondrocytes and BMSCs in vitro promotes the expression of cartilaginous extracellular matrix and, if so, what is the optimal ratio of the two cell types. Cultures of rabbit articular chondrocytes and BMSCs were expanded in vitro and then cultured individually or at a chondrocyte:BMSC ratio of 4:1, 2:1, 1:1, 1:2, 1:4 for 21 days and cultured in DMEM/F12. BMSCs were cultured in chondrogenic induction medium. Quantitative real-time RT-PCR and Western blot were used to evaluate gene expression. In the co-cultures, type II collagen and aggrecan expression increased on days 14 and 21. At the mRNA level, the expression of type II collagen and aggrecan on day 21 was much higher in the 4:1, 2:1, and 1:1 groups than in either the articular chondrocyte group or the induced BMSC group, and the best ratio of co-culture groups seems to be 2:1. Also on day 21, the expression of type II collagen and aggrecan proteins in the 2:1 group was much higher than in all other groups. The results demonstrate that the co-culture of rabbit chondrocytes and rabbit BMSCs at defined ratios can promote the expression of cartilaginous extracellular matrix. The optimal cell ratio appears to be 2:1 (chondrocytes:BMSCs). This approach has potential applications in cartilage tissue engineering since it provides a protocol for maintaining and promoting seed-cell differentiation and function.
软骨细胞和骨髓间充质干细胞（BMSCs）常用于软骨组织工程中的种子细胞。本研究旨在确定体外共培养兔关节软骨细胞和 BMSCs 是否能促进软骨细胞外基质的表达，如果能，两种细胞的最佳比例是多少。体外扩增兔关节软骨细胞和 BMSCs，然后分别或按软骨细胞：BMSC 比例为 4:1、2:1、1:1、1:2、1:4 培养 21 天，在 DMEM/F12 中培养。BMSCs 在软骨诱导培养基中培养。采用实时定量 RT-PCR 和 Western blot 评估基因表达。在共培养物中，第 14 天和第 21 天 II 型胶原和聚集蛋白聚糖的表达增加。在 mRNA 水平上，第 21 天，2:1、4:1 和 1:1 组的 II 型胶原和聚集蛋白聚糖表达明显高于单独的软骨细胞组或诱导的 BMSC 组，共培养组的最佳比例似乎为 2:1。同样在第 21 天，2:1 组的 II 型胶原和聚集蛋白聚糖蛋白表达明显高于其他所有组。结果表明，兔软骨细胞和兔 BMSCs 以特定比例共培养可促进软骨细胞外基质的表达。最佳细胞比例似乎为 2:1（软骨细胞：BMSCs）。这种方法在软骨组织工程中有应用前景，因为它提供了一种维持和促进种子细胞分化和功能的方案。
