Reconstruction of mandibular defects with tissue-engineered bone using 3D bionic printing technology / 中国组织工程研究

ABSTRACT

BACKGROUND: The 3D printed polylactic-co-glycolicacid/nano-hydroxyapatite (PLGA/nHA) scaffold carrying human recombinant bone morphogenetic protein 2 (rhBMP-2)/chitosan (CS) sustained release tissue-engineering bone has good biological activity, mechanical properties, and biological activity of its controlled release rhBMP-2. OBJECTIVE: To investigate the repair of mandibular defects with PLGA/nHA scaffold/rhBMP-2/CS sustained release tissue-engineering bone manufactured using 3D bionic printing technology. METHODS: Animal models of bilateral critical mandibular bone defects were established in 27 New Zealand white rabbits, followed by implantation of a 3D-printed PLGA/nHA scaffold/rhBMP-2/CS sustained release tissue-engineering bone on one side (experimental side), and a 3D-printed PLGA/nHA scaffold on the other side (control side). Mandibular specimens were harvested at postoperative days 30, 60 and 90 to carry out cone-beam CT, Micro CT, histological and immunohistochemical examinations. RESULTS AND CONCLUSION: The results from micro-CT analysis revealed that the volume of newly formed bone volume and the amount of bone trabeculae on the experimental side were significantly higher than those on the control side at different postoperative time points (P ＜ 0.05). The results from cone-beam CT examination showed that at 90 postoperative days, bone density of the bone defect on the experimental side was close to that of the surrounding bone, new bone tissues were full of the original bone defect area, and the trabecular bone arranged regularly, while on the control side, worm-eaten discontinuous low-density osteoid tissues were visible in the bone defect area. Osteogenesis on the experimental side was better than that on the control side. Histological findings demonstrated that on the experimental side, a large amount of mature lamellae were detected in the bone defect area, with well-arranged trabecular bones and abundant capillaries, and moreover, the scaffold material had been completely absorbed. However, low-density, loose-meshed, irregular braided bone tissues with rare capillaries were observed on the control side, and the scaffold material had been mostly absorbed. Immunohistochemical findings indicated that the osteocalcin-dyed area on the experimental side was significantly larger than that of the control side at postoperative 90 days. To conclude, 3D-printed PLGA/nHA scaffold/rhBMP-2/CS sustained release tissue-engineering bone is favorable for the repair and reconstruction of experimental mandibular defects in rabbits.