BACKGROUND Uniaxial/biaxial tensile stress has been employed to induce chondrocyte differentiation of mesenchymal stem cells. However, the effects of radial tensile stimuli on differentiation of MSCs into fibrocartilage remain unclear. RESULTS It was found that induced bone marrow mesenchymal stem cells (BMSCs) were not only similar to TMJ disc cells in morphology, but also could synthesize type I collagen (Col I), a small amount of type II collagen (Col II) and glycosaminoglycans (GAGs). The synthesis of Col I significantly increased while that of Col II gradually decreased with increasing tensile strength. The ratio of Col I to Col II was 1.8 to 1 and 2 to 1 in the 10% and 15% stretching groups, respectively. The gene expression of Col I and GAGs was significantly upregulated, whereas that of Col II was downregulated. However, the higher tensile stimulation (15%) promoted the synthesis of α-smooth muscle actin (α-SMA). Too much α-SMA is not conducive to constructing engineered tissue. CONCLUSION Therefore, the 10% radial tensile stimulus was the optimal strength for inducing the BMSCs to differentiate into fibrochondrocytes of the temporomandibular joint (TMJ) disc. This work provided a novel approach for inducing BMSCs to differentiate into fibrochondrocytes.

中文翻译：

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动态径向拉伸应力对骨髓间充质干细胞纤维软骨分化的影响。

背景技术单轴/双轴拉伸应力已被用于诱导间充质干细胞的软骨细胞分化。然而，径向拉伸刺激对MSCs分化成纤维软骨的影响尚不清楚。结果发现诱导的骨髓间充质干细胞（BMSCs）不仅在形态上与TMJ椎间盘细胞相似，而且可以合成I型胶原蛋白（Col I），少量II型胶原蛋白（Col II）和糖胺聚糖（GAG）。Col I的合成随着抗张强度的增加而显着增加，而Col II的合成则逐渐降低。在10％和15％拉伸组中，Col I与Col II的比例分别为1.8∶1和2∶1。Col I和GAGs的基因表达明显上调，而Col II的基因表达下调。然而，较高的拉伸刺激（15％）促进了α-平滑肌肌动蛋白（α-SMA）的合成。过多的α-SMA不利于构建工程组织。结论因此，10％的径向拉伸刺激是诱导BMSCs分化为颞下颌关节（TMJ）盘状软骨细胞的最佳强度。这项工作提供了一种诱导BMSCs分化为纤维软骨细胞的新方法。