In the present study we explore the extracellular matrix (ECM) produced by human bone marrow mesenchymal stem/stromal cells (BM-MSCs) induced to undergo osteogenic differentiation within porous chitosan/gelatin (CS:Gel) scaffolds by investigating their multiple gene expression profile and mechanical behavior. Initially, the efficiency of the BM-MSCs osteogenic differentiation within the constructs was confirmed by the significant rise in the expression of the osteogenesis associated genes DLX5, RUNX2, ALP and OSC. In line with these findings, OSC and Col1A1 protein expression was also detected in BM-MSCs on the CS:Gel scaffolds at day 14 of osteogenic differentiation. We then profiled, for the first time, the expression of 84 cell adhesion and ECM molecules using PCR arrays. The arrays, which were conducted at day 14 of osteogenic differentiation, demonstrated that 49 genes including collagens, integrins, laminins, ECM proteases, catenins, thrombospondins, ECM protease inhibitors and cell-cell adhesion molecules were differentially expressed in BM-MSCs seeded on scaffolds compared to tissue culture polystyrene control. Moreover, we performed dynamic mechanical analysis of the cell-loaded scaffolds on days 0, 7 and 14 to investigate the correlation between the biological results and the mechanical behavior of the constructs. Our data demonstrate a significant increase in the stiffness of the constructs with storage modulus values of 2 MPa on day 7, compared to 0.5 MPa on day 0, following a drop of the stiffness at 0.8 MPa on day 14, that may be attributed to the significant increase of specific ECM protease gene expression such as MMP1, MMP9, MMP11 and MMP16 at this time period.

在本研究中，我们通过研究它们的多基因表达谱来探索由人骨髓间充质干/基质细胞 (BM-MSCs) 诱导在多孔壳聚糖/明胶 (CS:Gel) 支架内进行成骨分化产生的细胞外基质 (ECM)和机械行为。最初，通过成骨相关基因DLX5、RUNX2、ALP和OSC表达的显着上升证实了构建体中 BM-MSCs 成骨分化的效率. 与这些发现一致，在成骨分化第 14 天，在 CS:Gel 支架上的 BM-MSC 中也检测到 OSC 和 Col1A1 蛋白表达。然后，我们首次使用 PCR 阵列分析了 84 个细胞粘附和 ECM 分子的表达。在成骨分化的第 14 天进行的阵列显示，49 个基因在接种在支架上的 BM-MSCs 中差异表达，包括胶原蛋白、整合素、层粘连蛋白、ECM 蛋白酶、连环蛋白、血小板反应蛋白、ECM 蛋白酶抑制剂和细胞粘附分子。与组织培养聚苯乙烯对照相比。此外，我们在第 0、7 和 14 天对载有细胞的支架进行了动态力学分析，以研究生物学结果与构建体力学行为之间的相关性。