Magnesium–Magnetic Field Synergy Enhances Mouse Bone Marrow Mesenchymal Stem Cell Differentiation into Osteoblasts Via the MAGT1 Channel

Abstract

Magnesium ion (Mg2+)-based materials are known to exert osteogenic effects that can be enhanced by the bioelectrical properties of magnetic fields. In this study, we examined the effect of a medium-strength static magnetic field (SMF), combined with a Mg2+-containing medium, on the proliferation and osteogenic differentiation of mouse bone marrow mesenchymal stem cells (BMSCs). Mouse BMSCs were divided into a control group, 7.5 mM Mg2+ group, 15 mT SMF group, and 7.5 mM Mg2+ plus 15 mT SMF group. Osteoblast proliferation was measured using a Cell Counting Kit-8 assay, whereas osteogenic differentiation was detected using alkaline phosphatase (ALP) staining and western blot analysis, respectively. The number and size of calcium nodules were determined using Alizarin Red staining. Compared with those in the control group, the ALP activity, calcium nodule formation, and osteogenic protein expression were promoted in other groups. In particular, Mg2+-SMF had a significant effect after 7 days of intervention and more effectively promoted BMSC differentiation and proliferation than either Mg2+ or the SMF alone, suggesting that Mg2+-SMF synergistically contributed to osteogenic differentiation and cell proliferation. To examine their roles in bone differentiation, the Magt1 and Creb1 genes were silenced in BMSCs, and the findings indicated that the synergistic intervention with Mg2+ and magnetic fields might exert osteogenic effects via the MAGT1 channel and CREB1 protein. This study provides an experimental basis for a potential Mg2+-SMF synergistic artificial bone material that could be clinically applied in the treatment of bone defects.