背景:前期研究已证实兔骨髓间充质干细胞在体外成骨诱导培养下可定向成骨分化,并能够稳定表达成骨细胞的特异性表型,具有成骨能力;且已证实带部分松质骨的小牛皮质骨支架材料具有良好的生物相容性和降解性,可以作为骨髓间充质干细胞的载体材料.目的:在前期研究基础上,根据骨组织工程学的基本原理,将骨髓间充质干细胞与小牛异种骨复合,植入新西兰大白兔髂骨内观察其成骨情况,为构建理想的初步组织工程骨工程化产品提供理论依据.方法:分别将兔骨髓间充质干细胞成骨诱导后复合的带部分松质骨小牛皮质骨(组织工程骨组)、单纯小牛异种骨(异种骨组)、自体髂骨(自体髂骨组)随机植入兔髂骨.观察各组植入物的表面变化和周围组织反应,植入后4,8,12,24周摄X射线片观察成骨情况,取材后利用免疫组织化学染色观察骨形态发生蛋白2的表达情况.结果与结论:异种骨植入兔髂骨后,伤口生长良好,没有全身和局部的炎症和毒性反应.X射线片显示组织工程骨组在术后24周时与宿主骨结合部基本愈合,而异种骨组术后24周与宿主骨愈合不满意.苏木精-伊红染色可观察到软骨化骨过程,免疫组织化学染色显示各时间点骨形态发生蛋白2染色阳性.体内实验结果表明兔骨髓间充质干细胞复合带部分松质骨的小牛皮质骨支架材料经体外诱导后具有在新西兰兔体内构建组织工程骨的能力.%BACKGROUND: Previous studies have confirmed that rabbit bone marrow mesenchymal stem cells (BMSCs) can differentiate into osteoblasts under osteogenic induction in vitro, stably express the specific phenotype of osteoblasts and have osteogenic ability. Calf cortical bone scaffold with partial cancellous bone has good biocompatibility and degradability, which can be used as a carrier material of bone marrow mesenchymal stem cells. OBJECTIVE: To combine rabbit BMSCs with calf bone composite according to the basic principles of bone tissue engineering and to observe the osteogenesis in the New Zealand white rabbits after implantation of BMSCs/calf bone composite into the ilium, thereby providing a direct evidence for preliminary clinical application of tissue-engineered bone products.METHODS: BMSCs/calf cortical bone scaffold with partial cancellous bone (tissue-engineered bone group), simple calf heterogeneous bone (heterogeneous bone group) or autologous iliac bone (autologous iliac bone group) was randomly implanted into the rabbit ilium. The changes of implant surface and tissue reactions around the implant were observed.X-ray examination was performed to observe osteogenic changes at 4, 8, 12, 24 weeks after implantation. Immunohistochemistry staining was used to observe the expression of bone morphogenetic protein 2.RESULTS AND CONCLUSION: After heterogeneous bone implantation, the wound healed well, and there were no systemic or local inflammation and toxicity reactions in all groups. The X-ray results showed that at postoperative 24 weeks, the implant was basically fused with the host bone in the tissue-engineered bone group, but the fusion was unsatisfactory in the heterogeneous bone group. The process of ossifications from cartilages was observed in all groups by hematoxylin-eosin staining, and bone morphogenetic protein 2 was positive for immunohistochemical staining. Findings from in vivo experiments indicate that rabbit BMSCs seeded onto the calf cortical bone scaffold with partial cancellous bone could construct tissue-engineered bone by osteoinductation in vitro in the rabbits.
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