体内外共同预构血管化对组织工程骨构建的作用及机制研究

Presently, constructing new bone tissues by means of bone tissue engineering is still not enough to meet the clinical needs due to the lack of adequate blood supply. The problem of extensive bone defects remains unsolved. The vascular endothelial cells (VECs) differentiated by bone marrow mesenchymal stem cells (BM-MSCs) which have multiple differentiation potential may form tube-like structure in appropariate scaffold materials, but as seed cells, their early survival is not guaranteed. In view of the above, we propose the method of prevascularization in vitro and vivo, in which we pre-seed the VECs in scaffold materials, and implant them in arteriovenous beams to be embedded in organism; when sufficient rete vasculosums are formed, they are seeded in osteoblasts (OB) which are implanted in situ to repair bone defects. Meanwhile, we will trace the seed cells by transferring the BM-MSCs with lentiviral vector labeled with RFP and eGFP so as to illustrate the function and related mechanism of seed cell prevascularization in long-term bone constructing. The effect of bone formation and the relationship between bone formation and vascularization will be examined by the technologies of imaging, histology, molecular biology, and fluorescence imaging techniques, etc. to demonstrate the effect of prevascularization on tissue engineering bone construction. The study will be of great significance to clarify the relationship between vascularization and bone formation, lay foundation for the clinical application in future, and provide a new idea for the technology of tissue engineering bone construction..

由于缺乏充足的血供，采用骨组织工程方法构建新生骨组织目前不能满足临床需要。大范围骨缺损的问题仍未解决。骨髓间充质干细胞（BM-MSCs）具有多向分化潜能，其诱导分化的血管内皮细胞（ECs）在适宜的支架材料中可形成管样结构，但其本身作为种子细胞却没有早期存活的保障。据此我们提出将ECs预先接种于支架材料中，再植入动静脉束包埋于机体内，待形成足够的血管网后，再接种成骨细胞(OB)植入原位修复骨缺损，即体内外共同预构血管化的方法。同时采用带绿色和红色双荧光基因的慢病毒载体转染BM-MSCs，对种子细胞进行示踪，阐明种子细胞预构血管化在远期骨构建中所起的作用及相关机制，利用影像学、组织学、分子生物学、荧光活体成像等技术观察成骨效果及成骨与成血管的关系，证实采用预构血管化方式能更有效构建组织工程骨。对阐明血管化与成骨关系的机制有重要意义，为应用于临床奠定基础，并为构建骨组织工程技术提供一种新思路