Effects Of Low-Intensity Electromagnetic Fields On The Proliferation And Differentiation Of Cultured Mouse Bone Marrow Mesenchymal Stem Cells

AIM:To study the effects of low-intensity electromagnetic fields [1] on proliferation, differentiation. cell cycle and the vivo effects of EMFs in rat bone marrow mesenchymal stem cells (BMSCs).METHODS:Harvested BMSCs were cultured for3generations and divided into4groups. The MTT assay was employed to evaluate cell proliferation, and alkaline phosphatase (ALP) activity was measured via a colorimetric assay in the3th,7th and10th day. Changes in cell cycle in7th day and bone nodule formation in12th day were also analyzed. Additionally, the expression of the collagen I gene was examined by RT-PCR in10th day. The BMSCs of irradiated group and control group were transplanted into cortical bone of different mice femurs separately with PLGA [poly(lactic-co-glycolic acid)] serving as a scaffold. After4and8weeks, specimens of mice were sliced and stained by H&E separately.RESULTS:The results showed that EMF(0.5mT.50HZ) accelerated the cellular proliferation(P<0.05), enhanced the cellular differentiation(P<0.05) and increased the the percentage of cells in G2/M+S phase (P<0.05)in the stimulation. The EMF-exposed groups had significantly higher collagen I mRNA levels than the control group (P<0.05). The EMF+osteogenic medium-treated group readily formed bone nodules.Hematoxylin and eosin (H&E) staining showed a clear flaking of bone tissue in the irradiated group.CONCLUSION:Irradiation of BMSCs with low-intensity EMFs (0.5mT,50HZ) increased cell proliferation and induced cell differentiation.