【摘要】 目的探讨不同频率低功率射频电磁场(0.1～40MHz)对DNA分子损伤的机理。方法琼脂糖凝胶电泳观察射频对离体质粒DNA分子的直接损伤作用;测定分析射频辐射后细胞内丙二醛(malondialdehyde,MDA)含量及超氧化物歧化酶(superoxidedismutase,SOD)活性的变化,RTPCR检测细胞DNA修复基因表达的改变。结果(1)低功率射频对pEGFPN2质粒DNA无明显直接作用;(2)40MHz和20MHz射频可使细胞内MDA的水平明显升高,并显著抑制SOD的活性,1MHz、0.1MHz频率电磁场作用未见显著影响;(3)40MHz射频抑制ERCC2、polβ基因的表达,对ERCC1基因无明显影响。结论低功率射频电磁场可增强细胞内脂质过氧化反应,抑制DNA修复基因表达,间接损伤细胞DNA分子。频率是影响电磁场生物效应的重要因素。更多还原

【Abstract】 Objective To study the damage mechanism of low power radiofrequency electromagnetic fields(RF-EMF) to DNA in the range of 0.1～40 MHz frequencies.Methods Agarose gel electrophoresis was applied to investigate the direct damage to plasmid DNA.The level of maleic dialdehyde (MDA) and the activity of superoxide dismutases (SOD) of SGC-996 gallbladder cancer cells exposured to RF-EMF were measured to analyze the change of free radicals.RT-PCR was applied to analyze the expression of DNA repair genes.Results Low power RF-EMF had no obvious direct effect on pEGFP-N 2 plasmid.40 MHz and 20 MHz EMF could raise significantly the level of cellular MDA and suppress the activity of SOD, but 1MHz and 0.1 MHz EMF had no obvious effect.40 MHz EMF inhibited the expressions of ERCC 2 and pol B genes, but had no obvious effect on ERCC1.Conclusion Low power RF-EMF can enhance over-oxidation reaction of lipid in cytoplasm, suppress the expression of DNA repair genes and result in DNA damage indirectly. Frequency can impact obviously on the biological effect and target of RF-EMF.更多还原