ABSTRACT
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.