The present study was aimed at identifying a new scaffold/stem cell combination useful to treat large bone defects. Human amniotic fluid stem cells (AFSCs) were expanded in vitro, labeled with a fluorescent cell‐permeable dye (PKH26) and transplanted in vivo in a femoral injured rat model. The femoral defect was left untreated (control rats) or filled with hydroxyapatite (HA; natural nanocrystalline carbonated hydroxyapatite‐Orthoss®) scaffold alone or loaded with PKH26‐labeled AFSCs. All animals were killed 3 weeks after implantation. Both gross anatomy and histological observations revealed a major bone regenerative response in rat specimens treated with HA scaffold, alone or supplemented with AFSCs. Samples injected with HA plus AFSCs displayed the presence of abundant fibrotic tissue, the formation of periosteal woven bone, and an increased presence of blood vessels in the bone marrow, with still fluorescent AFSCs in close proximity. These observations provide evidence that natural HA plus AFSCs represents a promising alternative therapeutic strategy to autologous bone grafting procedures.

中文翻译：

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天然纳米晶碳酸羟基磷灰石与人羊水干细胞（AFSCs）联合诱导的大鼠骨愈合

本研究旨在确定可用于治疗大骨缺损的新型支架/干细胞组合。人羊水干细胞（AFSC）在体外扩增，用荧光细胞可渗透染料（PKH26）标记，并在股骨损伤的大鼠模型中进行体内移植。股骨缺损未经治疗（对照组）或仅填充羟基磷灰石（HA；天然纳米晶碳酸羟基磷灰石Orthoss®）支架或装有PKH26标记的AFSC。植入3周后杀死所有动物。总体解剖学和组织学观察均显示，单独或补充AFSC的HA支架处理的大鼠标本具有主要的骨再生反应。注射HA加AFSC的样品显示存在丰富的纤维化组织，骨膜编织骨的形成，骨髓中血管的存在增加，并且仍带有荧光AFSC。这些观察结果提供了证据，证明天然HA加AFSC代表了自体骨移植程序的有前途的替代治疗策略。