骨髓基质细胞复合三维支架修复犬下颌骨节段性缺损

Experimental study on reconstruction of segmental mandible defect using tissue engineered bone combined ΒMSCs with 3-D TCP

目的:探讨犬骨髓基质细胞(bone marrow stromal cells,BMSCs)体外复合预制三维下颌骨缺损仿真β-磷酸三钙(β-TCP)支架对犬下颌骨节段性缺损进行修复的可行性。方法:通过计算机辅助设计/制作和快速原型技术,制作3cm长犬下颌骨节段性缺损β-磷酸三钙支架,体外接种第3代骨髓基质细胞,培养5d天后回植,对犬一侧下颌骨节段性缺损进行修复,并设单纯材料作为对照组。术后1周、1个月、3个月观察局部伤口情况,术后1、3个月行X线片和三维CT成像,术后3个月将标本进行生物力学检测和组织学观察。结果:X线片观察显示,术后3个月,对照组缺损区低密度影,BMSCs+β-TCP组缺损区见高密度组织;三维CT成像显示术后3个月,对照组修复区吸收明显,达1/2以上;BMSCs+β-TCP组修复区未见明显吸收;生物力学检测显示,对照组和BMSCs+β-TCP组的牙槽嵴高度分别为9.16mm和18.54mm,最大弯曲载荷分别为42.90N和102.77N,应力分别为1.930N/mm2和3.504N/mm2,应变分别为54.50%和16.98%。经统计学处理,均有显著性差异;组织学观察显示术后3个月,BMSCs+β-TCP组成骨良好,支架周围可见多核巨细胞吞噬材料,并可见软骨形成区。结论:应用β-TCP三维支架复合犬BMSCs进行犬下颌骨节段性缺损修复存在一定的可行性。

PURPOSE： To study the possibility of the segmental mandible reconstruction using combined dog＇s bone marrow stromal cells （BMSCs） with 3-dimentional β-tricalcium phosphate （β-TCP） in vivo. METHODS： 3-dimentional mandible defect scaffold 3cm in length was fabricated using CAD/CAM and rapid prototyping. The incubated 3th generated cells were seeded with 3-D scaffold, the constructs （n=3） was implanted to repair the segmental mandible defect. The control group was scaffold （no cells, n=3） implantation alone. 1 week, 1 month and 3 months postoperatively, the dogs were taken X ray films and 3-D CT scanning. And 3 months postoperatively, the mandibles were harvested, examined, radiographed, and prepared for biomechanical examination and histological evaluation. ANOVA was used for statistical analysis （with SPSS10.0 software package）. RESULTS： Radiograph displayed the higher radiodensity in group of BMSCs＋β-TCP than in the control group; 3-D CT image showed defect of the control group absorbed nearly 2/3 more than the group of plus cells; The mechanical examination showed the average height of the mandible of the two groups were 18.54 mm and 9.16mm, the compression strength was 102.77N and 42.90N, the stress was 3.504N/mm^2 and 1.930 N/ mm^2 with significant difference; Histological examination showed new bone formation in the scaffolds in central sections of the defects in the experimental group 3 months later. CONCLUSIONS： The construct of 3-D scaffold seeded BMSCs ensured bone formation and vascularization throughout the procedure of segmental mandible defect reconstruction, closely resembling how tissue engineering would be used to reconstruct a mandible in the clinical setting.