Extremely Low Frequency Electromagnetic Fields On The Immune Function And Cell Proliferation

Since the rapid development of the industry, the extremely low frequency electromagnetic fields (ELF-EMF) are widespread in the environment. The risks of human health arising from the ELF-EMF attract our attentions. In this thesis, we investigate mainly the influences of ELF-EMF on immunologic function in normal mouse. Meanwhile, the effects of ELF-EMF on the proliferation of mouse spleen cells and colon cancer cells in vitro are also studied. The studied results have important meaning to understand the biological effects of ELF-EMF, which can provide some valuable information for establishing the safe criterion of EMF.In the vitro investigation of the influences of ELF-EMF on immunological function of mice, The NK cells were extracted from mice and were exposed in the ELF-EMF (f=5Hz,E=0.4V/m, B=1mT) for 0,20,40,60,80,100 mins respectively. After incubation, the activity of NK cells was measured by MTT method.In vivo study of immunological functions on nonspecific immunity and humoral immunity in normal mice and mice pretreated with Cy, 32 mice were divided randomly into experiment and control groups, the experiment group was exposed in the ELF-EMF about 60 days; The control group was raised in the same condition without irradiation. The indexes of immunology of mice were detected by immunologic method after 60 days, in which the numbers of leucocytes in blood were measured by the microscope, the weights of antibody(IgG,IgM,IgA), complement(C3,C4) in serum were detected by certain reagent-boxes and semiautomatic instrument of biochemistry, respectively. In addition, the peritoneal macrophage phagocytosis capacity and immune organ index (thymus index and spleen index) were also measured.In the experiment of influences of ELF-EMF on cells, we used the mouse spleen cells and colon cancer cells in vitro cell models. The effects of the ELF-EMF exposure on morphology, cell proliferation were investigated by the methods of phase contrast microscope, MTT colorimetric assay.The results of the experiments are as follows:1. Cy can lead to the number of leukocytes reduced, the thymus index and the spleen index decreased, serum antibody(IgG,IgM,IgA) and complement(C3,C4) dropped, macrophage phagocytosis lower, mice in a state of low immune function. These show that the ELF-EMF can be an antagonistic role to Cy, mouse blood leukocyte number, the relative weight of the spleen, serum IgM and C3 content, macrophage phagocytosis of these immune indicators index rose; The ELF-EMF can also reinforce the normal mouse peritoneal macrophage phagocytosis, significantly increase serum IgG, IgM, C3 content of mouse, increase mouse spleen index. In addition, in the vitro experiment of time-dependence of the extremely low frequency electromagnetic radiation on activity of NK cells, we found that the activity of NK cells increased significantly which are exposed about 40-100min; with the increase of radiation time the activity of NK cells are increased and a peak occurs after the decline was parabolic. These results indicate that ELF-EMF can enhance the immunologic function and antagonize the inhibition of Cy on immunological function. This means that ELF-EMF can be an important means to improve the function of immune system in the future.2. In the vitro experiment of influences of ELF-EMF on cell proliferation, we found that the C26 cells have the unremarkable colonies, low speed of growth and differentiation, decreased of density as well as shrinking of synapsis along with the exposed time of ELF-EMF. With the longer exposed time, the spleen cells grow sooner. In the meanwhile some cells become larger, more abundant cytoplasm, unit area increased the number of cells.The results of MTT colorimetric assay show that the proliferation of C26 cells which are exposed in the ELF-EMF could be inhibited significantly when compared with the control group (p< 0.5).The inhibition effect is increased with the extension of the exposed time, enhanced at the beginning of a sharp increase, but the rate of increase is declined with the exposed time increasing farther. The extremely low frequency electromagnetic radiation can enhance the proliferation activity of mouse spleen cells when compared with the control group (p< 0.5), the proliferation increased with the extending of the exposed time. The impact of ELF-EMF on the C26 cells is greater than that of the spleen cells.