Effect of Pulsed Electromagnetic Fields on Osteogenic Differentiation and Wnt/β-catenin Signaling Pathway in RatBone Marrow Mesenchymal Stem Cells

Objective To investigate the effect of pulsed electromagnetic fields (PEMFs) on osteogenic differentiation and Wnt/β-catenin signaling pathway in rat bone marrow mesenchymal stem cells (BMSCs). Methods Rat BMSCs were isolated and the passage 3 cells were divided into 3 groups. Cells were cultured in LG-DMEM complete medium for 1 d to ensure fully adherent. Then, change the medium. Cells were maintained in complete medium (Control group) or in osteo-induction medium (OM group). The cells in PEMFs group were cultured in complete medium and exposed to 8 Hz, 3.8 mT PEMF stimulation for 40 min/d. The intervention lasted for 21 d. Cell proliferation activity was determined by using MTT. The effects of PEMF onosteogenic differentiation were assessed by ALP and Alizarin Red S staining. Various osteoblast-relevant genes and genes of Wnt/β-catenin signaling were analyzed by quantitative real-time RT-PCR. Results We found that OM could significantly promote the proliferation of BMSC at 7 d, 14 d, 21 d (P<0.05), but the effect was not obviously found in PEMFs group. For osteogenic differentiation, the positive rates of ALP or Alizarin Red S staining were detected higher in PEMFs/OM group （P<0.05）. Quantitative RT-PCR revealed PEMFs or OM could increase mRNA levels of Wnt1, Wnt3a, LRP5, β-catenin, BMP-2, Runx2, ALP, OC at special time point （P<0.05）. Compared to OM group, PEMFs have a lower expression in each detection, but the trends were consistent.　　 Conclusion PEMFs (8 Hz, 3.8 mT) could induce the osteogenic differentiation of rat BMSCs via activating Wnt/β-catenin signaling pathway.