The Effects Of Power Frequency Homogeneous Magnetic Field On Apoptosis And Proliferation Of Normal And Tumor Cells

With the rapid development of modern scientific technology, the human being environment is flood with more and more complicated electromagnetic field. The researches for the biological effect of electromagnetic field are regarded increasingly, and the effect of power frequency homogeneous magnetic field on apoptosis and proliferation of cells is one of the important problems among them. The effects of power frequency homogeneous magnetic field (PFHMF) on apoptosis and proliferation of normal and tumor cells are studied and compared in this thesis.1. Firstly, the current researches for biological effects of electromagnetic field are summarized, the natural fields and the fields caused by human beings are introduced, and the researches aspects and the development of biological effects are comprehensively analyzed in depth.2. Establishment of 50 Hz Power Frequency Homogeneous Magnetic FieldBased on study and comparison of the basic magnetic field generating structure and theories, the 50 Hz PFHMF was successfully established.3. The effects of PFHMF exposure on normal cellsThe results showed that the apoptosis rates of murine hepatocytes and thymocytes exposed to PFHMF were significantly higher than that in control group. As the exposure time extended (5 to 120mins), the apoptosis rates of murine hepatocytes and thymocytes increased correspondently. Thus the result confirmed that PFHMF exposure could induce apoptosis of normal murine cells in vivo. On the contrary, no effects of PFHMF exposure on apoptosis as well as the expression of apoptosis related gene bcl-2 and caspase-3 of HPBLs in vtro were found. No significant effects of PFHMF exposure on proliferation of normal cells were found in vivo and in vitro.4. Effects of PFHMF exposure on the proliferation and apoptosis of human gastric cancer cell line -SNU in vitro and possible mechanismsFCM analysis showed that apoptosis rate of SNU was increased in PFHMF exposure groups. The apoptotic rate increased as the exposure time prolonged increased. Ultrastructurally, chromatin condensation and apoptosis body were found in SNU cells in PFHMF exposure groups. The expressions of bax and caspase-3 in all PFHMF exposure groups were higher than that in control (P<0.05), a significant time-depended response correlation could be found between the expressions of Bax and caspase-3 and the time of PFHMF exposure, while the adverse result were found for expression of bcl-2.Confocal microscope analysis revealed that intracellular calcium-ion concentration of SNU cells increased after PFHMF exposure and reached a peak value at the time of 30 minutes.Thus, the results in this study showed that PFHMF exposure could induce apoptosis of human gastric cancer cells in vitro. Bax, bcl-2 and caspase-3 were involved in apoptotic process.No effect of PFHMF exposure on SNU cells cycle and proliferation were found in the study.5. Comparative observation of the effects of PFHMF exposure at completely same condition on tumor cells and hepatocytes and thymocytes in H22 tour bearing mice.The results showed that the apoptosis rates of tumor cells in H22 tumor bearing mice after repeated PFHMF exposure were significantly higher than that in control group, a significant dose-depended response correlation could be found between apoptosis rate and time of PFHMF exposure. The result suggested that PFHMF exposure could induce apoptosis of tumor cells in mice in vivo. At the same time, it was found that the apoptosis rates of normal hepatocytes and thymocytes of H22 bearing mice were also increased as compared with control. Comparison of the apoptosis inducing effects between H22 cells and normal cells revealed that the effect of PFHMF exposure on apoptosis of H22 cells were several times higher than that of normal cells in the same mice.An interesting phenomenon of this study is that the proliferation of tumor cells in H22 bearing mice was significantly inhibited after PFHMF exposure for 6 days, while the proliferation of normal lymphocytes and hepatocytes in the same mouse was...