Comparison of cellular responses of mesenchymal stem cells derived from bone marrow and synovium on combined silk scaffolds

As a brand new member in mesenchymal stem cells (MSCs) families, synovium-derived mesenchymal stem cells (SMSCs) have been increasingly regarded as a promising therapeutic cell species for musculoskeletal regeneration. However, there are few reports mentioning ligamentogenesis of SMSCs and especially null for their engineering use towards ligament regeneration. The aim of this study was to investigate and compare the cellular responses of MSCs derived from bone marrow and synovium on combined silk scaffolds that can be used to determine the cell source most appropriate for tissue-engineered ligament. Rabbit SMSCs and bone marrow-derived mesenchymal stem cells (BMSCs) were isolated and cultured in vitro for two weeks after seeding on the combined silk scaffolds. Samples were studied and compared for their cellular morphology, proliferation, collagen production, gene, and protein expression of ligament-related extracellular matrix (ECM) markers. In addition, the two cell types were transfected with green fluorescent protein to evaluate their fate after implantation in an intraarticular environment of the knee joint. After 14 days of culturing, SMSCs showed a significant increase in proliferation as compared with BMSCs. The transcript and protein expression levels of ligament-related ECM markers in SMSCs were significantly higher than those in BMSCs. Moreover, 6 weeks postoperatively, more viable cells were presented in SMSC-loaded constructs than in BMSC-loaded constructs. Therefore, based on the cellular response in vitro and in vivo, SMSCs may represent a more suitable cell source than BMSCs for further study and development of tissue-engineered ligament.