筋膜包裹的骨髓间充质干细胞/聚己内酯复合体血管化组织工程骨修复比格犬骨缺损

背景：骨组织工程技术的材料/细胞复合物已能在肌肉、皮下等异位组织内成骨，或是在小型哺乳动物的骨缺损处修复成骨，但这与临床的实际仍有较大差距，骨组织工程技术能否修复大型哺乳动物大范围的骨缺损，以及如何促进组织工程骨的体内再血管化进程还不明确。 目的：观察应用比格犬带血管蒂深筋膜瓣及组织工程骨在体内的成骨情况。 方法：分离培养比格犬骨髓间充质干细胞，将骨髓间充质干细胞以自然沉淀法进行组织构建，接种于聚己内酯材料上，与支架材料复合。在比格犬左足胫骨中段制作骨-骨膜缺损模型，植入以筋膜包裹的骨髓间充质干细胞/聚己内酯复合体作为实验组；右足制作胫骨中段骨-骨膜缺损模型后，植入骨髓间充质干细胞/聚己内酯复合体；另取2只犬制作骨-骨膜缺损模型不植入任何材料作为空白对照。术后进行大体、X射线片、组织学、磁共振灌注成像观察骨模具上成骨细胞生长与血管化情况。 结果与结论：空白对照组无新骨生成，无血管长入，最后缺损由纤维瘢痕组织填充；对照组8~16周骨缺损逐渐被骨样组织填充，可见较多的骨痂，骨痂向移植物长入，断端连接不完全，髓腔硬化。实验组成骨过程及速度明显优于对照组，术后6周骨痂量较多，术后8周支架材料已完全降解，术后12周骨缺损完全修复，可见大量松质骨形成，新骨髓腔较通畅，骨皮质连续较牢靠，所形成的血管在数量、孔径和发布上均明显优于对照组。提示组织工程骨有较强、较快修复大动物大段负重骨缺损的能力，而带蒂的筋膜瓣则通过促进其再血管化而使其这种能力得到更好的发挥。

Repair of beagle canine defects with fascia-encapsulated bone marrow mesenchymal stem cells/poly-lactone complex

BACKGROUND: Bone tissue engineering materials/cell complex has been able to live in the muscle, subcutaneous tissue, and other heterotopic bones, or in small mammals to repair bone defect. However, there is still much practical and clinical gap, such as bone tissue engineering and technical ability to repair large bone defects in big mammals, as well as how to promote the in vivo tissue-engineered bone revascularization process. OBJECTIVE: To observe the bone formation using beagle deep fascia pedicled flap and tissue-engineered bone. METHODS: Beagle bone marrow mesenchymal stem cells were isolated, cultured, and inoculated on poly-lactone (PCL). Bone/bone membrane defect was induced in middle tibia on the left side of beagle. Then, the defect was implanted with fascia-encapsulated bone marrow mesenchymal stem cells (BMSCs), considering as experimental group. The second defect was induced in the middle tibia on the right side of beagle and implanted with BMSCs/PCL, considering as control group. The third defect was induced in 2 additional beagles without any implantation, considering as blank control group. Gross observation, X-ray test, histology, and magnetic resonance perfusion imaging were performed on the models to observe growth and osteoblasts and vascularization. RESULTS AND CONCLUSION: There was no new bone formation and blood vessels growth in the blank control group, and the defect was filled by fiber scar tissues finally. After 8-16 weeks, the bone defect was gradually filled by bony tissue, and more calluses which grew in implants were observed. The broken ends of fractured bone were not intact, and pulp cavity was sclerotic. Bone formation in the experimental group was rapid than in the control group. After 6 weeks, a great quantity of calluses was observed; after 8 weeks, stent materials were completely degraded; after 12 weeks, bone defect was successfully repaired. A great quantity of cancellated bones was observed, the newborn cavitas medullaris was smooth, and cortical bone was successive and stable. The amount, pore diameter, and distribution of formed blood vessels in the experimental group were superior to those in the control group, suggesting that tissue-engineered bone was able to effectively and rapidly repair bone defect in some animal. Fascia flap could promote the revascularization in vivo of tissue-engineered bone.