中文摘要：

为了模拟体内成骨微环境,为骨组织工程提供一种调控干细胞体外向成骨细胞定向分化的共培养新方法,SD大鼠骨髓间充质干细胞和包埋在海藻酸钠-聚赖氨酸-海藻酸钠（alginate-poly-lysine-alginate,APA）微胶囊中的SD大鼠成骨细胞进行体外共培养。共培养过程中,通过碱性磷酸酶（ALP）定量、定性分析以及钙化结节（von Kossa）染色等手段来评价骨髓间充质干细胞向成骨细胞定向分化。结果表明在体外微囊化共培养过程中,被诱导细胞的胞内ALP酶活性逐渐高于对照组的干细胞,接近于成骨细胞;ALP以及von Kossa定性染色证实被诱导细胞具有较高的ALP活性以及具有分泌钙基质的能力。微囊化成骨细胞和外部干细胞的共培养体系较好地模拟了体内干细胞向成骨细胞转化的成骨微环境,促进了干细胞向成骨细胞的体外定向分化;微胶囊膜将成骨细胞和干细胞进行了隔离,避免了两者的直接接触和可能的细胞交叉污染混合,同时利于分离目的细胞,这种微囊化共培养体系为骨组织工程提供了一种安全调控干细胞体外成骨定向分化的工程化新方法。

英文摘要：

A novel coculture method was provided for bone tissue engineering to simulate in vivo osteogenic microenvironment and regulate oriented differentiation of stem cells in vitro.BM（bone marrow） mesenchymal stem cells（MSCs） derived from SD（Sprague Dawley） rats were cocultured with osteoblasts microencapsulated in alginate-poly-lysine-alginate（APA） microcapsules in this study.During microencapsulated coculture,the quantitative and qualitative analysis of alkaline phosphatase（ALP） and von Kossa staining were performed to assess the osteogenic differentiation of BM MSCs.During microencapsulated coculture,the ALP quantitative activity in target cells is higher than that in MSCs and is close to that in osteoblasts gradually.And the qualitative staining of ALP and von Kossa confirm that the cells after microencapsulated coculture have higher ALP activity and could secrete calcium deposit.Microencapsulated coculture simulates the in vivo osteogenic microenvironment and accelerates the osteogenic differentiation of stem cells in vitro.Microcapsule membrane separates BM MSCs from osteoblasts so that the immunoreaction and mixing between these two types of cells are avoided in this coculture system.This study indicates that the microcapsule could be a novel coculture protocol to control ex vivo oriented differentiation of stem cells,and microencapsulated coculture system can provide a novel method for stem cell oriented differentiation in bone tissue engineering.