Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Yishan Rd 600, Shanghai, 200233, China.
Calcif Tissue Int. 2020 May;106(5):509-517. doi: 10.1007/s00223-019-00656-4. Epub 2020 Feb 26.
Distraction osteogenesis (DO) is a clinically effective procedure to regenerate large bone defects. However, the treatment duration is undesirably lengthy, especially in elderly patients. Exosomes derived from mesenchymal stem cells (MSC-Exos) could exert the beneficial effects while avoiding the possible complications of stem cell transplantation. This study aimed to evaluate the effects of MSC-Exos on bone regeneration during DO in older rats. Exosomes were isolated from the supernatants of young bone marrow mesenchymal stem cells (BMSCs) through ultra-centrifugation, and characterized using transmission electron microscopy, western blot, and tunable resistive pulse sensing analysis. The effects of MSC-Exos on the proliferation and differentiation of older BMSCs were evaluated using CCK-8 assay, ALP and ARS staining, and qRT-PCR. Unilateral tibial DO model was established on older Sprague-Dawley rats and MSC-Exos or phosphate buffer saline was locally injected into the distraction gaps after distraction weekly. Bone regeneration were evaluated using X-ray, Micro-CT, mechanical test, and histological staining. The MSC-Exos were round or cup-shaped vesicles ranging from 60 to 130 nm in diameter and expressed markers including CD9, CD63, and TSG101. The in vitro results indicated that MSC-Exos could enhance the proliferation and osteogenic differentiation of older BMSCs. Bone regeneration was markedly accelerated in rats treated with MSC-Exos according to the results of X-ray, micro-CT, and histological analysis. The distracted tibias from the MSC-Exos group also demonstrated better mechanical properties. These results suggest that MSC-Exos promote DO-mediated bone regeneration in older rats through enhancing the proliferation and osteogenic capacity of BMSCs.
牵张成骨术（DO）是一种有效的临床方法，可以再生大的骨缺损。然而，治疗时间不理想地长，特别是在老年患者中。间充质干细胞（MSC）衍生的外泌体（MSC-Exos）可以发挥有益的作用，同时避免干细胞移植的可能并发症。本研究旨在评估 MSC-Exos 对老年大鼠 DO 过程中骨再生的影响。通过超速离心从年轻骨髓间充质干细胞（BMSC）的上清液中分离出外泌体，并通过透射电子显微镜、western blot 和可调电阻脉冲传感分析进行表征。通过 CCK-8 测定、ALP 和 ARS 染色以及 qRT-PCR 评估 MSC-Exos 对老年 BMSC 增殖和分化的影响。在老年 Sprague-Dawley 大鼠中建立单侧胫骨 DO 模型，在牵开每周后将 MSC-Exos 或磷酸盐缓冲盐水局部注入牵开间隙。通过 X 射线、Micro-CT、力学试验和组织学染色评估骨再生。MSC-Exos 呈圆形或杯形囊泡，直径为 60 至 130nm，表达包括 CD9、CD63 和 TSG101 在内的标志物。体外结果表明，MSC-Exos 可增强老年 BMSC 的增殖和成骨分化。根据 X 射线、Micro-CT 和组织学分析的结果，用 MSC-Exos 处理的大鼠的骨再生明显加快。MSC-Exos 组的牵开胫骨也表现出更好的力学性能。这些结果表明，MSC-Exos 通过增强 BMSC 的增殖和成骨能力来促进老年大鼠 DO 介导的骨再生。
