Objective

This study aimed to investigate effects of TGF-β1-containing exosomes derived from bone marrow mesenchymal stem cells (BMSC) on cell function of rotator cuff tenocytes and its implication to rotator cuff tear.

Methods

The primary BMSC and rotator cuff tenocytes were extracted and cultured. Identification of BMSC were performed by observing cell morphology and measurement of surface biomarkers by flow cytometry. BMSC-derived exosomes were extracted and identified by using electron microscopy, nanoparticle-tracking analysis (NTA) and western blotting. Cell proliferation and cell cycle were measured by CCK-8 assay and flow cytometry assay, respectively. Transwell assay was used for detection of tenocytes migration. The fibrotic activity of tenocytes was determined via qPCR and western blotting assays.

Results

BMSC and BMSC-derived exosomes were successfully extracted. Treatment of BMSC-derived exosomes or TGF-β1 promoted cell proliferation, migration and increased cell ratio of (S + G2/M) phases in tenocytes, as well as enhanced the expression levels of fibrotic activity associated proteins. However, inhibition of TGF-β1 by transfection of sh-TGF-β1 or treatment of TGFβR I/II inhibitor partially reversed the impact of BMSC-derived exosomes on tenocytes function.

Conclusion

Taken together, TGF-β1-containing exosomes derived from BMSC promoted proliferation, migration and fibrotic activity in rotator cuff tenocytes, providing a new direction for treatment of rotator cuff tendon healing.

中文翻译：

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源自骨髓间充质干细胞的含有 TGF-β1 的外泌体促进肩袖肌腱细胞的增殖、迁移和纤维化活性

客观的

本研究旨在探讨来自骨髓间充质干细胞 (BMSC) 的含有 TGF-β1 的外泌体对肩袖肌腱细胞功能的影响及其对肩袖撕裂的影响。

方法

提取和培养原代 BMSC 和肩袖肌腱细胞。通过观察细胞形态和通过流式细胞术测量表面生物标志物来鉴定 BMSC。通过使用电子显微镜、纳米粒子追踪分析 (NTA) 和蛋白质印迹法提取和鉴定 BMSC 衍生的外泌体。分别通过CCK-8法和流式细胞术测定细胞增殖和细胞周期。Transwell 试验用于检测肌腱细胞迁移。通过 qPCR 和蛋白质印迹测定确定肌腱细胞的纤维化活性。

结果

成功提取了 BMSC 和 BMSC 衍生的外泌体。处理 BMSC 衍生的外泌体或 TGF-β1 可促进细胞增殖、迁移并增加肌腱细胞中 (S + G2/M) 期的细胞比率，并提高纤维化活性相关蛋白的表达水平。然而，通过转染 sh-TGF-β1 或处理 TGFβRI/II 抑制剂来抑制 TGF-β1，部分逆转了 BMSC 衍生的外泌体对肌腱细胞功能的影响。

结论

综上所述，来自 BMSC 的含有 TGF-β1 的外泌体促进了肩袖肌腱细胞的增殖、迁移和纤维化活性，为肩袖肌腱愈合的治疗提供了新的方向。