| Abstract: | Effect of Low-Frequency Pulsed Electromagnetic Fields (PEMFs) has been considered as a stimulator for rat osteoblasts (ROBs) maturation and mineralization. However, the mechanism of the PEMFs-induced osteogenesis is still unknown. In this study, we examined the role of the PI3K/AKT/GSK3β/β-catenin signaling pathway in PEMFs-induced maturation and mineralization of ROBs. First, the ROBs were exposed at the PEMFs in different magnetic field strengths,then intracellular, alkaline phosphatase (ALP) activity was detected to find outthe best magnetic field strength for promotion of osteogenic differentiation; Second, protein expression levels of PI3K, AKT, GSK3β, p-GSK3β, and β-catenin were detected by Western blot after PEMFs treatment for different times; Finally, we used the PI3K specific inhibitors to block the PI3K signaling pathway, and then detected the bone-related indicators. We also detected ALP activity, calcium salt deposition and RUNX2, BMP2 gene expression of bone-related indicator, as well as downstream protein expression levels of the signaling pathway and related the nuclear translocation of transcription factors. The results showed that when the magnetic field strength of PEMFs was 0.6 mT, the ALP activity was the highest; by PEMFs treatment for different times, there was no change in the total protein levels of PI3K and AKT, but p-PI3K, p-AKT,p-GSK3β and β-catenin expression was improved, as well as nuclear translocation of β-catenin was detected. With the effect of PEMFs, ALP activity and the bone-related indicators were increased. The calcium salt deposition increased capacity and the BMP2/Smad1/5/8 signaling pathway was activated. When PI3K specific inhibitors were applied, all the above phenomena disappeared. Collectively, we demonstrated that the magnetic field strength of PEMFs exposed to 0.6 mT has the most obvious effect of promoting osteogenic differentiation and activating PI3K/AKT/GSK3β/β-catenin signaling; If the pathway was inhibited, the osteogenesis of PEMFs was offset. The results suggested that 0.6 mT PEMFs can promote the mineralization and maturation of osteoblasts through the PI3K/AKT/GSK3β/β-catenin signaling pathway, which provides a theoretical basis for the treatment of osteoporosis with pulsed electromagnetic fields. |
