The Bioeffect And Mechanism Of Medium Frequency Alternating Magnetic Fields On Glioma Cells

?Background? Glioma is the most common malignant tumor in the central nervous system.It is mainly treated by surgical treatment,combining adjuvant radiation therapy and chemotherapy.Unfortunately,for high-grade glioma,it is difficult to completely remove the tumor tissue,and patients are prone to relapse or have poor prognosis after the operation.In addition,tumor in the brain functional area and the glioma that repeatedly relapse after surgery do not meet the surgical indications.Even if treated with the auxiliary comprehensive treatments such as radiotherapy and chemotherapy,the patients will still have poor prognosis,short lifetime and multiple complications,seriously affecting their life quality.Based on traditional treatment,scholars have been looking for treatments with less side effects and more extensive applicability.With the rapid development of science and technology,the interdisciplinary cooperation and interdisciplinary research become more extensive and in-depth.The crossover development of physics and medicine has greatly promoted the treatment combining biological and physical methods in the field of medicine.Especially in the research of treating malignant tumor with magnetic field therapy,researchers at home and abroad have made some progresses.Studies have shown that the magnetic field of specific parameters has the effect of inhibiting tumor cell proliferation.It also can enhance the sensitivity of chemotherapy drugs in killing cancer cells.However,because of the complexity,multi-dimension and functional diversity of the magnetic field parameters,researchers have not yet been able to identify a certain magnetic field parameter which can inhibit tumor growth and meet the demand of clinical application,or to have key breakthroughs in understanding the mechanism of how it inhibits tumor cell proliferation.This paper studies the influence of alternating magnetic field on the growth of glioma cells and hopes to lay a foundation of finding and screening the suitable magnetic parameters for inhibiting the proliferation of glioma cells.?objectives and Methods?In the experiments of this paper,through measuring the biological differences of cell proliferation,apoptosis,clone formation and migration ability between the glioma group and the control group exposing to the alternating magnetic field(grouped by different parameters such as frequency and intensity),we tried to find an appropriate magnetic field parameter to inhibit glioma cell proliferation.The apoptosis of glioma cells was studied by flow cytometry,Hoechst staining and Annexin V-FITC and PI double standard staining.The expression of apoptosis-related proteins in glioma cells was detected by using WB method.The effect of alternating magnetic field on the cell cycle of glioma was determined by flow cytometry.The effects of alternating magnetic field on the survival and tumor growth in animal models were studied by using the tumor model.?Result?The cell proliferation experiment(MTT assay)and the clone formation experiment confirmed that in the groups with magnetic field intensity of 5m T and 10 m T,frequency of 100 KHz,200KHz and 300 KHz,the proliferation of glioma cells was significantly inhibited.Morphological studies by HE staining showed that under the specific alternating magnetic field(magnetic field strength was 5m T,10 m T,and frequency was 100 KHz,200 KHz,300 KHz),the growth condition of glioma cells was worse than that of the control group,which was indicated by decreased cell density,poor adhesive ability and more floating cells.In the group with 5m T,10 m T magnetic field intensity and 100 KHz,200KHz,300 KHz magnetic field frequency,the apoptosis rate of the glioma cells was increased compared with the control group.By Hoechst staining,Annexin V-FITC and PI double staining methods,the glioma cells exposed in the alternating magnetic field with 5 m T,10 m T magnetic field intensity and 100 KHz,200 KHz,300 KHz magnetic field frequency,had some changes in their morphology,such as nuclear margination and nuclear fragmentation,showing a typical apoptosis changes.The western blot confirmed that after exposure to the magnetic field whose intensity was 10 m T,and frequency was 200 KHz,the expression of apoptosis-related proteins,Bax/Bcl-2,Caspase 3 and Cleaved Caspase 3 was increased.In addition,all the magnetic field intensities and the frequencies of alternating magnetic field used in this experiment have no significant effects on the migration ability and the cell cycle of glioma cells.10 m T intensity and 200 KHz frequency of alternating magnetic field had no significant effects on the survival time and tumor volume(or volume percentage)of the tumor-bearing rats.?Conclusion?When the intensity of alternating magnetic field is 5m T,the frequency is 200 KHz or the intensity is 10 m T,the frequency is 200 KHz,the proliferation can be inhibited and apoptosis can be induced in rat glioma F98 cells.