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Objective To evaluate the effects of static magnetic fields (SMFs) of different intensity and exposure duration on the proliferation and apoptosis of human umbilical cord endothelial cells (HUVECs),and their release of nitric oxide (NO),6-keto-prostacyclin 1α (6-keto-PGF1α) and endothelin (ET-1).Methods Cultured HUVECs were exposed to a SMF at 5,22,86 or 135 mT for 8,12 or 24 hours.Their proliferation and apoptosis were monitored by flow cytometry (FCM).The medium was collected to test its NO content by optical density.ET-1 and 6-keto-PGF1α were measured by radioimmunization.Results ( 1 ) The proliferation of HUVECs increased when the cells were exposed to a SMF at 5 mT for 8 h,but a SMF at 135 mT for 12 h or 24 h inhibited the proliferation of HUVECs.(2)An SMF had no effect on apoptosis of HUVECs.(3)An SMF at 5 mT for 8 h increased the release of NO and 6-keto-PGF1 a,but the release of NO and 6-keto-PGF1 a decreased when the SMF intensity was 135 mT or the cells were exposed to an SMF for 12 h or 24 h.(4) An SMF at 5 mT or 22 mT for 8 h did not effect the release of ET-1.An SMF at 86 mT or 135 mT increased the release of ET-1.Compared with a control group,an SMF at 5 mT for 12 or 24 h did not affect the release of ET1,but at 22,80 or 135 mT,the release of ET-1 decreased significantly.Conclusions Exposure to a low intensity SMF for a short duration could improve the proliferation of HUVECs and increase the release of vasoactive factors,but if HUVECs are exposed to a strong SMF or exposed for a long duration,the proliferation and the release of vasoactive factors is decreased.
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Objective: To observe the effect of static magnetic fields(SMF) on the proliferation of bone mesenchymal stem cells(MSC) in human. Methods: The MSC were obtained by using gradient centrifuge method, and then selected by the adhesive method. The third generation cells were irradiated by use of static magnetic fields at different intensities for 5 days(8 h/d). The method of MTT was employed to evaluate the level of proliferation. The parameters regarding the variation of the cell cycle were detected with the flow cytometry(FCM). Results: As compared to the control group, the proliferative rate of the MSC exposed to 0.05 mT SMF was significantly higher; there was no difference between the 0.10 mT group and control group; howere, cell proliferation was attenuated significantly when SMF intensity was 0.50 mT and 1.00 mT. No abnormal ploidy was found in any group. Conclusion: The effect of SMF on the proliferation of MSC is dependent on the magnetic intensity. 0.05 mT SMF can accerate the proliferation of MSC. 0.10 mT SMF have no effects on the growth of MSC. Wherease, 0.50 mT and 1.00 mT SMF can attenuate the growth of MSC.
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0.05).Conclusion:It suggests that HPDLFs exposured to static magnetic field produced by magnetic attachment have little mutagenic effects on chromosomes and DNA.
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Objective To study the effect of static magnetic fields on the micronucleus in polychromatic erythrocytes(PCE) in the bone marrow and and the lipid peroxidation in the brain tissue in mice.Methods Fourty Kunming mice were randomly divided in to the negative control group,positive control group(cyclophosphamide:145 mg/kg) and the static magnetic fields(20,40,50,60,80 and 100 mT) exposure group,exposed twice a day,for two hours each time.After 15 days,the micronuclei rate of the bone marrow,blood cells and the activity of superoxide dismutase(SOD),the protein malonaldehyde(MDA) were determined.Results Compared with the control,the micronuclei rate in 50,60,80 and 100 mT exposure group increased significantly,the amount of leukocyte significantly decreased,the activity of SOD in the brain tissue in 60,80 and 100 mT exposure group decreased and the content of MDA increased significantly.Conclusion The present experiment demonstrats that static magnetic fields exposure at doses of 50,60,80 and 100 mT may induce the micronuclei rate increase,the amount of leukocyte decrease,the activity of SOD in the brain tissue decrease and the content of MDA increase.