Tissue-engineered composite scaffold of poly(lactide-co-glycolide) and hydroxyapatite nanoparticles seeded with autologous mesenchymal stem cells for bone regeneration

组织工程复合支架聚乳酸-羟基乙酸共聚物和羟基磷灰石纳米粒子接种自体骨髓间充质干细胞应用于骨再生（英文）

Objective： A new therapeutic strategy using nanocomposite scaffolds of grafted hydroxyapaUte （g-HA）/ poly（lactide-co-glycolide） （PLGA） carried with autologous mesenchymal stem cells （MSCs） and bone morphogenetic protein-2 （BMP-2） was assessed for the therapy of critical bone defects. At the same time, tissue response and in vivo mineralization of tissue-engineered implants were investigated. Methods： A composite scaffold of PLGA and g-HA was fabricated by the solvent casting and particulate-leaching method. The tissue-engineered implants were prepared by seeding the scaffolds with autologous bone marrow MSCs in vitro. Then, mineralization and osteogenesis were ob- served by intramuscular implantation, as well as the repair of the critical radius defects in rabbits. Results： After eight weeks post-surgery, scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDX） revealed that g-HNPLGA had a better interface of tissue response and higher mineralization than PLGA. Apatite particles were formed and varied both in macropores and micropores of g-HNPLGA. Computer radiographs and histological analysis revealed that there were more and more quickly formed new bone formations and better fusion in the bone defect areas of g-HNPLGA at 2-8 weeks post-surgery. Typical bone synostosis between the implant and bone tissue was found in g-HNPLGA, while only fibrous tissues formed in PLGA. Conclusions： The incorporation of g-HA mainly im- proved mineralization and bone formation compared with PLGA. The application of MSCs can enhance bone for- mation and mineralization in PLGA scaffolds compared with cell-free scaffolds. Furthermore, it can accelerate the absorption of scaffolds compared with composite scaffolds.

目的:对应用接枝的羟基磷灰石(g-HA)/聚乳酸-羟基乙酸共聚物(PLGA)纳米复合支架接种自体骨髓间充质干细胞(MSCs)和骨形态发生蛋白2(BMP-2)治疗重症骨缺损的新的治疗策略进行评估,并通过肌肉内移植研究人工骨的组织相容性和移植物在体内的矿化和缺损骨的愈合。创新点:改性的PLGA接种自体MSCs的组织工程骨加速了骨缺损的愈合,使临床重症骨缺损的治疗有了新的手段。方法:应用溶剂浇铸和粒子沥滤方法将PLGA和g-HA制备成复合支架g-HA/PLGA。在g-HA/PLGA支架上接种兔自体MSCs制成组织工程移植物。取宽0.3 cm长2.0 cm的上述移植物埋入兔背部肌肉内,8周后取出移植物,使用扫描式电子显微镜(SEM)检测人工骨的组织相容性(图3a),X射线能量色散谱(EDX)分析钙浓度。然后,用锯锯掉兔前肢桡骨骨干2.0 cm,取同样长度的上述移植物放置于骨缺损处(图4)。术后2、4、8周应用计算机X线摄影(CR)检测骨缺损愈合情况(图5),组织学分析愈合组织结构(图6),SEM检测人工骨与周围组织的相容性(图7),反转录聚合酶链式反应(RT-PCR)检测愈合组织Collagen I、Collagen II和Bmp-2基因的表达。结论:PLGA掺入g-HA主要改善了矿化作用,有益于骨相关基因的表达和骨形成。自体MSCs的应用增强了骨形成和PLGA支架的矿化作用,并加速了支架的吸收。