Adverse Biological Effects Of Microwave In Combination With γ-ray Radiation On Nerve Cells

Objective: To explore adverse effects induced by low intensity microwave andγ-ray radiation on SHG44 cells and cultured gliocytes in order to provide experimental data for health protection and clinical application.Methods: SHG44 cells were randomly divided into control group(M0),2,4 and 6 mW/cm² microwave treatment groups(named as M2,M4 and M6,respectively),γ-ray group(IM0) and combined groups(named as IM2,IM4 and IM6,respectively). Cultured gliocytes were divided into M0,M4,IM0 and IM4 groups. Microwave treatment was 2h/d for 3d,and the combined groups were given 5 Gy ⁶⁰Coγ-ray on the fourth day. (1) Proliferation activity was measured by cck-8 assay. (2) Cell cycle and apoptosis were detected by flow cytometer. (3) Ca²⁺-Mg²⁺-ATPase activity and LDH activity were determined using commercial kits. (4) MMP and Ca²⁺ were detected by flow cytometer and Confocal Laser scanning Microscopy.Results: (1) Cell proliferation activity in cultured gliocytes was significantly decreased by microwave andγ-ray radiation treatment but not in SHG44 cells. The proliferation activity of gliocytes in IM4 group also increased. (2) The rate of apoptosis slightly increased in SHG44 cells after microwave andγ-ray radiation , and the rate of necrosis greatly increased in the combined treatment group. The rate of apoptosis significantly increased in cultured gliocytes byγ-ray radiation. (3) LDH activity increased in gliocytes in the IM0 and IM4 groups. (4) G1, G2/M and S phase did not change obviously by microwave radiation in the two cells. The percentage of G1 and S phase cells in SHG44 decreased byγ-ray radiation,while that of G2/M phase increased.For cultured gliocytes, the G1 phase did not change much but the S phase decreased and G2/M phase increased significantly. (5) Ca²⁺ greatly increased in the two cells treated by microwave andγ-ray radiation , with much higher levels of IM4 and IM6 of SHG44 cells. There was a linear correlation between Ca²⁺ and apoptosis levels. (6) MMP decreased in SHG44 cells by microwave andγ-ray radiation , with much lower levels in IM4 and IM6 groups.(7) Ca²⁺-Mg²⁺-ATPase activity decreased in SHG44 cells after microwave andγ-ray radiation. The difference was statistical different in the M6 and combined treatment groups. For cultured gliocytes, Ca²⁺-Mg²⁺-ATPase activity decreased in all groups.Conclusion: (1) Adverse biological effects were observed in SHG44 cells exposed to microwave andγ-ray radiation, and microwave could enhance the effect ofγ-ray to some degree. (2) Microwave inhibited cellular proliferation in cultured gliocytes, but did not enhance or lessen the effect ofγ-ray. (3) The overloading of Ca²⁺, the decline of MMP and the degradation of Ca²⁺-Mg²⁺-ATPase activity were involved in the synergetic effect of microwave toγ-ray.