Effects of pulsed electromagnetic fields on the proliferation of bone marrow mesenchymal stem cells
- VernacularTitle:脉冲电磁场对小鼠骨髓间充质干细胞增殖的影响
- Author:
Zhenhua FANG
- Publication Type:Journal Article
- From:
Chinese Journal of Tissue Engineering Research
2007;11(42):8590-8593
- CountryChina
- Language:Chinese
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Abstract:
BACKGROUND: As a non-invasive therapy, pulsed electromagnetism fields (PEMFs) have been confirmed to have definite clinical efficacy on bone nonunion and other orthopaedic diseases. However, the action of bone marrow mesenchymal stem cells (MSCs) in the treatment of fracture by PEMFs is always neglected due to the restriction of previous knowledge.OBJECTIVE: To observe the proliferation and changes of cell cycle of MSCs in mice under PEMFs of 50 Hz, sine waves, at different intensity and different time, so as to find out the optimal window for intervention.DESIGN: A single-sample, grouped design, comparative observation of cell culture in vitro.SETTING: Department of Orthopaedics, Puai Hospital of Tongji Medical College, Huazhong University of Science and Technology.MATERIALS: Twenty BALB/C mice of 4-5 weeks old, weighing 18-22 g, either male or female, clean degree, were provided by the experimental animal center of Tongji Medical College [No. SYXK(E)2004-0028]. The animal experiment met the requirements of animal ethics. Pulse magnetic field generator was designed and manufactured by the Department of Electrical Engineering, Naval University of Engineering.METHODS : The experiments were carried out in the orthopaedic laboratory of Puai Hospital of Tongji Medical College, Huazhong University of Science and Technology from January to June in 2004. Mice MSCs were isolated using the density gradient centrifugation, then screened by means of adhesion, and the mice MSCs of the 3rd passage that grew well were treated with 50 Hz sine-wave PEMFs of 4, 3, 2 and 1 mT respectively, twice a day, 30 minutes for each time, with an interval of 12 hours. The stem cells untreated with PEMFs were taken as the control group.MAIN OUTCOME MEASURES: At 24, 48 and 72 hours after irradiation, the level of MSCs proliferation was detected with methyl-thiazol-tetrazolium (MTT) assay, cell cycle was analyzed with flow cytometer, and the influence of PEMFs on the proliferation of mice MSCs was expressed as proliferation index (PI).RESULTS: Effect of PEMFs on the proliferation of mice MSCs: There were no significant differences after irradiation for 24 and 48 hours between the PEMFs intervention groups and control group (P＞0.05). The proliferated MSCs after irradiation for 72 hours in the PEMFs intervention groups were significantly more than those in the control group (P＜0.05-0.01), and which was the most obvious by PEMFs of 1 mT (P＜0.01). Effect of PEMFs on the cell cycle of mice MSCs: No cell with abnormal DNA ploidy (diploid: 100%) was observed in all the samples. The PI values after PEMFs intervention of 1, 2, 3 and 4 mT for 72 hours were significantly higher than that in the control group (P ＜0.05-0.01), which was the most obvious by PEMFs of 1 mT (P＜0.01).CONCLUSION: Pulsed electromagnetism fields of 50 Hz, sine waves and intensity of 1 mT for 72 hours could obviously promote the proliferation of mice MSCs in vitro, this being the optimal window for intervention.
