Department of Orthopaedics, 920th Hospital of Joint Logistic Support Force, PLA, No. 212 Daguan Road, Kunming, Yunnan 650032, China.
Department of Orthopaedics, 920th Hospital of Joint Logistic Support Force, PLA, No. 212 Daguan Road, Kunming, Yunnan 650032, China.
Gene. 2024 Feb 15;895:148002. doi: 10.1016/j.gene.2023.148002. Epub 2023 Nov 16.
Rotator cuff tears (RCTs) are culprit of shoulder pain and dysfunction. Tendon-bone interface (TBI) mal-healing is an essential contributor to retear after RCTs. Consequently, present project was conducted to investigate the role of bone marrow mesenchymal stem cells (BMSCs)-derived exosomes on TBI healing.
Young BMSCs (Y-BMSCs) and Aged BMSCs (A-BMSCs) were isolated from Young (3-month-old) and old (24-month-old) SD rats, and their-derived exosomes (A-BMSCs-exo and Y-BMSCs-exo) were identified. RCTs model was established, and A-BMSCs-exo and Y-BMSCs-exo were injected at the rotator cuff using hydrogel as a vehicle. Pathological changes of TBI were observed by HE, Sirius Red and Oil Red O staining. Western blotting and RT-qPCR were applied to assess the expression of extracellular matrix (ECM)-, tendon cell (TCs)-, osteogenic-, tendon-derived stem cell (TDSCs)- and angiogenic-associated proteins and mRNAs in TBI.
Y-BMSCs exhibited increased activity, osteogenic and lipogenic abilities than A-BMSCs. After A-BMSCs-exo and Y-BMSCs-exo treatment, TBI displayed massive sharpey's fibers growing along the tendon longitudinally, and a collagen fiber-chondrocyte migration zone forming a typical tendon-noncalcified fibrocartilage-calcified fibrocartilage-bone structure. A-BMSCs-exo and Y-BMSCs-exo significantly upregulated the expression of collagen Col I/II/III, Aggrecan, TNMD, SCX, Runx2, OPN, CD45, Sox2, CD31 and VEGFR2 in TBI. In vitro, A-BMSCs-exo and Y-BMSCs-exo significantly enhanced the activity of TCs and TDSCs, TDSCs stemness, and reduced the osteogenic and lipogenic capacity of TDSCs. The effect of Y-BMSCs-exo was significantly stronger than that of A-BMSCs-exo.
BMSCs-derived exosomes facilitate ECM remodeling, osteogenic differentiation, angiogenesis, and stemness of TDSCs, thereby accelerating TBI healing in RCTs, with better outcomes using young individual-derived BMSCs.
肩袖撕裂（RCTs）是导致肩部疼痛和功能障碍的罪魁祸首。肌腱-骨界面（TBI）愈合不良是 RCTs 后再撕裂的一个重要因素。因此，本项目旨在研究骨髓间充质干细胞（BMSCs）衍生的外泌体对 TBI 愈合的作用。
从小鼠（3 月龄）和老年（24 月龄）SD 大鼠中分离出年轻（Y）BMSCs 和老年（A）BMSCs，并鉴定其来源的外泌体（A-BMSCs-exo 和 Y-BMSCs-exo）。建立 RCTs 模型，并使用水凝胶作为载体将 A-BMSCs-exo 和 Y-BMSCs-exo 注射到肩袖处。通过 HE、天狼猩红和油红 O 染色观察 TBI 的病理变化。应用 Western blot 和 RT-qPCR 评估 TBI 中外泌体相关的细胞外基质（ECM）、肌腱细胞（TCs）、成骨、肌腱源性干细胞（TDSCs）和血管生成相关蛋白和 mRNAs 的表达。
Y-BMSCs 的活性、成骨和成脂能力均高于 A-BMSCs。在 A-BMSCs-exo 和 Y-BMSCs-exo 处理后，TBI 显示大量Sharpey's 纤维沿肌腱纵向生长，胶原纤维-软骨细胞迁移区形成典型的肌腱-非钙化纤维软骨-钙化纤维软骨-骨结构。A-BMSCs-exo 和 Y-BMSCs-exo 显著上调了 TBI 中胶原 Col I/II/III、聚集蛋白聚糖、TNMD、SCX、Runx2、OPN、CD45、Sox2、CD31 和 VEGFR2 的表达。体外实验表明，A-BMSCs-exo 和 Y-BMSCs-exo 显著增强了 TCs 和 TDSCs 的活性、TDSCs 干性，并降低了 TDSCs 的成骨和成脂能力。Y-BMSCs-exo 的作用明显强于 A-BMSCs-exo。
BMSCs 衍生的外泌体促进了 TBI 中 ECM 重塑、成骨分化、血管生成和 TDSCs 的干性，从而加速了 RCTs 中的 TBI 愈合，使用年轻个体来源的 BMSCs 效果更好。
