Tendon and ligament injuries are not uncommon in clinics and have poor self-healing capacity due to their bloodless and slow-proliferative nature. Promoting the repair or reconstruction of an injured structure is an urgent problem. While Scleraxis (Scx) is a highly specific tendon cell marker, its function has not been explored to a large extent. Hence, Recombinant adenovirus was used to study the influence of Scx overexpression on directional differentiation of human amniotic mesenchymal stem cells (hMSCAs). hAMSCs modified with Scx could dramatically enhance the gene expression of tendon-related molecules, containing Scx, collagens I and III, Tenascin-C, fibronectin, matrix metalloproteinase-2 (MMP-2), lysyl oxidase-1 (LOX-1) and Tenomodulin at all-time points (P < 0.05), and the secretion of collagen I and III, fibronectin and Tenascin-C over time (P < 0.05) but did not impact the cell proliferation capacity (P > 0.05). Immunofluorescence staining showed the cobweb-like fusion of collagen I and fibronectin in the AdScx group on day 7, with higher average fluorescence intensity than the control (P < 0.05). After mixing with Matrigel, transplants were subcutaneously implanted in nude mice, obvious inflammation and rejection of immune response were not observed and HE staining showed a histological feature of swirl of fibers is closely linked in parallel in hAMSCs modified with Scx. On the contrary, in the control group, an unorganized connective structure with cell distributed randomly was spotted. The results of promoted directional differentiation of stem cells and the spatial structure of the normal tendon tissue in three-dimensional space manifested that Scx can be used as a specific marker for tendon cells, and as a positive regulator for directional differentiation of hAMSCs, which is possible to be applied to novel therapeutics for clinical tendon and ligament injury by hAMSCs modified with Scx.

中文翻译：

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通过巩膜过表达增强人羊膜间充质干细胞的肌腱分化和肌腱样组织形成。

肌腱和韧带损伤在诊所中并不少见，并且由于其无血和增殖缓慢的特性而具有较差的自愈能力。促进受损结构的修复或重建是一个紧迫的问题。尽管巩膜（Scx）是一种高度特异性的肌腱细胞标志物，但其功能尚未得到广泛的研究。因此，使用重组腺病毒来研究Scx过表达对人羊膜间充质干细胞（hMSCAs）定向分化的影响。用Scx修饰的hAMSC可以显着增强肌腱相关分子的基因表达，其中包括Scx，I型和III型胶原，腱生蛋白C，纤连蛋白，基质金属蛋白酶2（MMP-2），赖氨酰氧化酶1（LOX-1）和腱膜调节蛋白在所有时间点（P <0.05）以及胶原I和III的分泌，纤连蛋白和腱生蛋白-C随时间的推移（P <0.05），但不影响细胞增殖能力（P> 0.05）。免疫荧光染色显示第7天，AdScx组的胶原蛋白I和纤连蛋白呈蜘蛛网状融合，平均荧光强度高于对照组（P <0.05）。与Matrigel混合后，将移植物皮下植入裸鼠中，未观察到明显的炎症反应和免疫反应排斥，HE染色显示在用Scx修饰的hAMSC中，纤维涡旋的组织学特征平行紧密地联系在一起。相反，在对照组中，发现了具有随机分布的细胞的无组织结缔结构。