周期性牵张应变对大鼠骨髓间充质干细胞神经向分化的影响

目的 研究周期性牵张应变对大鼠骨髓间充质干细胞(rat bone marrow-derived mesenchymal stem cells, rBMSCs)向神经细胞分化的影响。方法 对rBMSCs加载不同幅度周期性应变24 h,然后继续培养5 d,检测神经细胞标志物表达和相关信号通路蛋白磷酸化水平。通过有限元分析牵张作用下细胞表面的应力分布。通过转录组测序分析周期性牵张应变引起差异表达的基因。结果 5%幅度、0.5 Hz周期性牵张应变可以显著促进神经细胞标志物的表达，提高细胞内胞外信号调节激酶(extracellular-signal-regulated kinase, ERK)、蛋白激酶B (AKT)和哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin, mTOR)的磷酸化水平。KEGG通路富集分析发现，与细胞黏附、细胞外基质和受体相互作用相关的基因在周期性牵张作用后显著提高。结论 周期性牵张应变可以改变细胞与细胞外基质的相互作用，激活AKT/mTOR和ERK信号通路，从而促进rBMSCs向神经细胞分化。了解力学刺激对间充质干细胞分化的影响有望提高...

Effects of Cyclic Strain on Neural Differentiation of Rat Bone Marrow-Derived Mesenchymal Stem Cells

Objective To study the mechanical effects of cyclic strain on neural differentiation of rat bone marrow mesenchymal stem cells (rBMSCs). Methods The rBMSCs were subjected to cyclic strain for 24 hours andthen cultured for 5 days. The expression of neural markers and the phosphorylation of relative signaling pathway proteins were evaluated. The stress distribution on cell surface was analyzed by finite element method. The differentially expressed genes induced by strain were identified by RNA sequencing analysis. Results The 0. 5 Hz strain with 5% magnitude could significantly induce higher expression of neural markers and elevated phosphorylation level of extracellular-signal-regulated kinase (ERK), protein kinase B (AKT) and mammalian target of rapamycin ( mTOR). KEGG pathway analysis showed that the focal adhesion and ECM-receptor interaction were significantly enriched under cyclic strain. Conclusions Cyclic strain could change the interaction of cells with the extracellular matrix ( ECM) and enhance the AKT/ mTOR and ERK pathway, finally promote rBMSC neural differentiation. Knowledge about the impact of mechanical stimulation on BMSC neural differentiation is expected to improve the efficiency of stem cell differentiation, shed light on device design for tissue engineering, and promote clinical application of mesenchymal stem cells in neural issue repair and regeneration.