活性仿生骨序贯控释生物活性因子促进成骨的作用及机制研究

The bone grafting procedures occupy the second place in all tissue transplantation. It remains some disadvantages, although bone-grafting materials have been fabricated with significant capability to promote osteogenesis. In recent years, the biomimetic designing biomaterials are becoming more and more popular. Our previous studies have demonstrated that the biomimetic mineralized silk fibroin (SF-HAp) materials were similar to the natural bone matrix with certain osteogenic ability, but very difficulty in healing the bone defects. Stromal cell derived factor -1 (SDF-1) promotes the recruitment of bone marrow mesenchymal stem cells (BMSCs), and bone morphogenetic protein 2 (BMP-2) has the most osteoinductive capacity. Therefore, we put forward the following hypothesis, SF-HAp scaffolds loaded with factors of SDF-1 and BMP-2 could repair the bone defect by regulating sequential release of dual growth factors. The potential mechanisms could be that the complex activates some signal pathways, which leads to the expression of key genes and promote recruitment and osteogenic differentiation of BMSCs. In order to verify the hypothesis, the study is designed to develop biomimetic scaffold (SF-HAp/SDF-1/BMP-2) and to explore the mechanism of migration and osteogenic differentiation of BMSCs both in vivo and in vitro.Besides, the gene chip technology and biotechnology is employed to determine the key genes and correlative signaling pathways associated with osteogenesis at the level of molecular, cellular, tissue and animal.

骨移植手术量居所有组织移植术的次席，而目前的植骨材料虽然成骨效能显著，但也存在一些不足。近年的发展趋势是以仿生理念设计与合成材料。我们的研究表明仿生矿化丝素蛋白（SF-HAp）与自然骨基质结构类似，具有一定的成骨能力，但修复骨缺损的能力有限。而基质细胞衍生因子-1（SDF-1）可募集骨髓间充质干细胞（BMSCs）迁移，骨形态发生蛋白2（BMP-2）是最强的成骨因子。因此，我们提出假说：利用SF-HAp复合SDF-1和BMP-2，通过序贯释放两种活性因子，刺激某些成骨信号通路和关键基因表达，促进BMSCs迁移并成骨分化而修复骨缺损。为了验证该假说，本项目拟构建SF-HAp/SDF-1/BMP-2，探讨促进BMSCs体内外迁移与成骨分化作用，采用基因芯片技术结合生物信息方法，分析相关信号通路和关键基因的表达，从分子、细胞、组织及动物水平层次探讨成骨分子学机制，以期为构建仿生植骨材料提供新思路。

以仿生理念设计和合成骨移植材料可能突破目前植骨材料的瓶颈。我们前期研究表明仿生矿化丝素蛋白（SF-HAp）与天然骨细胞外基质结构具有相似性，但尚缺乏骨缺损修复能力。目前研究表明，基质细胞衍生因子-1（SDF-1）募集骨髓间充质干细胞，骨形态发生蛋白2（BMP-2）是有效促成骨的细胞因子。因此，我们提出假说：利用SF-Hap负载SDF-1和BMP-2，设计序贯促进BMSCs迁移并成骨分化的骨修复材料。为了验证该假说，我们构建了SF-Hap/SDF-1/BMP-2复合支架，借助体外细胞迁移、qRT-PCR、Western Blot等分子生物学技术表征该支架成骨性能，采用基因芯片技术结合生物信息方法，分析相关信号通路和关键基因的表达，从分子、细胞、动物等多维度研究骨修复的作用和机制，为构建仿生植骨材料提供新思路。