Effects of exposure to electromagnetic fields on osteogenic differentiation and proliferation of rats' bone marrow mesenchymal stem cells / 中华物理医学与康复杂志

ABSTRACT

Objective To study the effects of electromagnetic field (EMF) on the activation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) pathways in mesenchymal stem cells (MSCs) and their interaction, and to explore the cellular signal transduction mechanism of the biological effects induced by EMF.Methods The 3rd-passage rat bone marrow MSCs were randomly divided into a control group, an EMF group, an EMF + PD98059 group and an EMF + SB202190 group.Cells in the EMF group were cultured in the electromagnetic field, those in the EMF + PD98059 and EMF + SB202190 groups cultured in the electromagnetic field after PD98059 or SB202190 was added, and those in the control group were cultured normally.Different groups of cells were exposed to electromagnetic fields (15 Hz, 1 mT, sine wave form) for different exposure duration.The activated phosphorylated and non-phosphorylated p38MAPK were measured using Western blotting analysis with their specific corresponding antibodies.The alkaline phosphatase (ALP) activity in cells in different groups was detected according to the instructions of ALP kit.MTT assay was applied to investigate the proliferation of cells.Results Electromagnetic fields could rapidly induce the activation of p38 MAPK (P ＜ 0.05) and the phosphorylation of p38 MAPK elevated after 15 min exposure to EMF.The phosphorylation of p38 MAPK was significantly lower in the EMF + SB202190 group than that of the EMF group.After 5 days of EMF exposure, the ALP activity of cells was significantly improved, and the effect could be inhibited by SB202190.The bone marrow mesenchymal stem cells proliferation increased significantly after being exposed to EMF for 3 days, and it could not be blocked by SB202190.Phosphorylation of ERK and MAPK increased significantly when the p38 MAPK pathway was blocked by SB202190 and exposed to EMF for 5 minutes, and it also increased significantly when the ERK MAPK pathway was blocked by PD98059 and received 30 minutes of EMF exposure.Conclusion EMF can quickly activate ERK and p38 MAPK pathways to induce cell proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells.Moreover, in EMF there is a mutual interference between ERK and p38 MAPK pathways.