Peritendinous fibrosis represents a fibrotic healing process that usually occurs after tendon injury or surgery. This worldwide challenge hampers the functional rehabilitation and the mobility of extremities. However, effective treatment is still lacking at present. The aim of our study was to explore the effect of extracellular vesicles derived from hydroxycamptothecin primed human umbilical cord stem cells (HCPT-EVs) on post-traumatic tendon adhesion. Extracellular vesicles derived from unprimed human umbilical cord mesenchymal stem cells (Unprimed EVs) or HCPT-EVs were isolated and characterized. A rat model of Achilles tendon injury was used to confirm the anti-adhesion effect of HCPT-EVs and compared with that of Unprimed EVs in vivo. In vitro, the inhibitory effects of HCPT-EVs on fibroblast proliferation, viability, and myofibroblast differentiation upon TGF-β1 stimulation were compared with the effects of Unprimed EVs. For mechanistic analysis, the expression of endoplasmic reticulum stress (ERS)-associated proteins was examined among the effector cargos of HCPT-EVs and Unprimed EVs. The ERS antagonist salubrinal was used to determine the ERS dependence of the anti-adhesion effects of HCPT-EVs. There were no obvious differences between Unprimed EVs and HCPT-EVs in terms of morphology, particle size, characteristic protein expression, and cellular uptake. HCPT-EVs exhibited a fortified anti-adhesion effect after Achilles tendon injury compared with Unprimed EVs. Fibroblast proliferation and viability and myofibroblast differentiation were all inhibited by HCPT-EVs. These properties were superior for HCPT-EVs relative to Unprimed EVs. Mechanistically, HCPT-EVs contained more ERS-associated protein than Unprimed EVs and activated the ERS pathway in fibroblast to counteract myofibroblast differentiation. This study demonstrates that HCPT-EVs show high anti-adhesion potential for the treatment of tendon injury by provoking ERS in fibroblasts. HCPT-EVs represent a promising strategy for clinical use in treating adhesion-related diseases.

中文翻译：

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羟基喜树碱致敏的脐带干细胞的细胞外囊泡增强了抗粘连能力，可用于治疗肌腱损伤

围发性纤维化代表通常在肌腱损伤或手术后发生的纤维化愈合过程。这一全球挑战阻碍了肢体的功能康复和活动。但是，目前仍然缺乏有效的治疗方法。我们研究的目的是探讨源自羟基喜树碱引发的人脐带血干细胞（HCPT-EV）的细胞外囊泡对创伤后肌腱黏附的影响。分离并鉴定了源自未启动的人脐带间充质干细胞（未启动的EV）或HCPT-EV的细胞外囊泡。阿喀琉斯腱损伤的大鼠模型用于确认HCPT-EV的抗粘连作用，并与未灌注的EV在体内进行了比较。在体外，HCPT-EV对成纤维细胞增殖，活力，将TGF-β1刺激后的成肌细胞和成纤维细胞分化与未启动电动汽车的效果进行了比较。为了进行机理分析，检查了HCPT-EV和未启动EV的效应蛋白中内质网应激（ERS）相关蛋白的表达。ERS拮抗剂salubrinal用于确定HCPT-EV的抗粘连作用的ERS依赖性。未启动的电动汽车和HCPT-电动汽车在形态，粒径，特征蛋白表达和细胞摄取方面没有明显差异。与未涂底漆的电动车相比，HCPT-EV在跟腱损伤后表现出增强的抗粘连作用。HCPT-EV可抑制成纤维细胞的增殖和活力以及成纤维细胞的分化。HCPT-EV的这些性能要优于未灌注的EV。机械上，HCPT-EV比未启动的EV包含更多的ERS相关蛋白，并激活了成纤维细胞中的ERS通路以抵消成肌纤维细胞的分化。这项研究表明，HCPT-EVs通过激发成纤维细胞中的ERS，具有很高的抗粘连潜力，可用于治疗肌腱损伤。HCPT-EV代表了一种临床上有望用于治疗粘连相关疾病的策略。