骨髓间充质干细胞增殖与成骨分化中电磁场激活ERK通路的作用

背景：研究表明电磁场可调节骨髓间充质干细胞的增殖和分化,但其具体机制尚不清楚。目的：从ERK信号途径探讨电磁场诱导大鼠骨髓间充质干细胞增殖与分化成骨的作用。方法：取第3代生长良好的大鼠骨髓间充质干细胞,暴磁组给予15Hz、1mT的正弦波电磁场刺激,PD98059＋暴磁组在电磁场刺激前给予20μmol/L ERK阻断剂PD98059,PD98059组仅给PD98059不进行电磁场刺激,对照组正常培养。电磁场刺激后,收集各组细胞,Western blot法检测ERK通路的活性,MTT法检测细胞增殖活性,碱性磷酸酶试剂盒检测细胞碱性磷酸酶活性。结果与结论：电磁场刺激后,细胞ERK1/2磷酸化水平、细胞的增殖活性、及碱性磷酸酶活性均明显升高（P〈0.01）;PD98059可明显抑制ERK1/2磷酸化水平及细胞增殖活性的升高（P〈0.01）,而在一定程度上提高细胞的碱性磷酸酶活性（P〈0.01）。说明电磁场刺激可通过激活骨髓间充质干细胞ERK信号通路,并且主要通过该途径促进骨髓间充质干细胞的增殖;而在脉冲电磁场促进骨髓间充质干细胞分化成骨的过程中,激活ERK信号通路所起的作用较小。

Effects of electromagnetic field activated-ERK signaling pathway on proliferation and osteogenic differentiation of rat bone marrow mesenchymal stem cells

BACKGROUND： It has been demonstrated that electromagnetic field （EMF） can adjust proliferation and differentiation of bone marrow mesenchymal stem cells,but the specific mechanism is not clear.OBJECTIVE： To investigate the effects of EMF-activated ERK1/2 pathway on proliferation and osteogenic differentiation of rat bone marrow mesenchymal stem cells.METHODS： The 3rd passage of rat bone marrow mesenchymal stem cells were received EMF treatment （15 Hz,1 mT,sine wave）,20 μmol/L PD98059 ＋ EMF treatment,or only PD98059 treatment.Simultaneously,a normal control group was established.Western blotting was applied to detect the activation of ERK signal pathway after EMF exposure.MTT assay was used to determine the activation of proliferation of cells.And alkaline phosphatase （ALP） activity in cells was detected by an ALP kit.RESULTS AND CONCLUSION： The ERK1/2 phosphorylation,proliferation and ALP activity of rat bone marrow mesenchymal stem cells were remarkably increased after exposure to EMF （P 0.01）.PD98059 could effectively block the increasing of ERK1/2 phosphorylation and cell proliferation （P 0.01）,but elevate ALP activity in a certain level （P 0.01）.EMF stimulation can fast activate ERK1/2 signal pathway and then promote the proliferation of rat bone marrow mesenchymal stem cells,however,ERK1/2 signal pathway activation has a less effect on osteogenic differentiation of bone marrow mesenchymal stem cells.