【作者】 陈波；

【导师】 许正平；

【作者基本信息】 浙江大学 ， 劳动卫生与环境卫生学， 2007， 硕士

【摘要】 随着移动通讯的迅猛发展和移动电话的日益普及，人们暴露于射频电磁场(Radiofrequency Electromagnetic Fields，RF EMF)的强度和时间也在不断增长，其可能的健康影响已引起公众和政府的广泛关注。一些流行病学调查显示射频场暴露能增加人群肿瘤等疾病发生的危险性，也有流行病学报道提示两者没有相关性；此外，国内外开展了大量的体内和体外试验研究以探讨RF EMF的生物学效应，但至今尚未取得一致性的结果，也不能解释现有的流行病学调查结果。因此，当前的研究重点应该是阐明射频电磁场的生物学效应和作用机制。DNA断裂是评价环境因素毒效应的常用生物标志物，也是细胞凋亡及对一些环境压力反应的起始信号，能够从机制角度考察射频电磁场可能产生的生物效应，特别是可能存在的诱癌或促癌效应。为此，本论文以γ-H2AX的形成这一DNA双链断裂(double-strand break，DSB)的早期事件作为指标，研究了SAR(Specific Absorption Rate)为3.0W/kg的GSM 1800 MHz射频电磁场间断辐照(5min开/10min关)对胚胎干细胞DNA的作用。对于每个样品，至少统计60个细胞的γ-H2AX焦点形成情况，并将焦点数超过5个的细胞定义为γ-H2AX焦点阳性细胞，以此计算阳性细胞率。研究结果显示，细胞受SAR为3.0 W/kg的GSM 1800 MHz射频电磁场间断辐照1h、6h和24h后，和假辐照组相比其平均阳性细胞率都有所上升，但统计学上无显著性意义(p＞0.05)。为深入考察该电磁场辐照对DNA的影响，本论文同时采用γ-H2AX焦点数等级分析法，即统计γ-H2AX焦点数为0、1-5、6-10和＞10个的细胞在总细胞中所占的百分比，结果显示1h、6h和24h射频电磁场辐照导致的γ-H2AX各焦点数等级细胞所占的百分比与假辐照组相比没有统计学上的显著差异(p＞0.05)。因此，基于本实验结果，我们得出以下结论：SAR为3.0 W/kg的GSM1800 MHz射频电磁场间断辐照1h、6h和24h对小鼠胚胎干细胞DNA无明显的损伤作用。更多还原

【Abstract】 The human exposure intensity and time to radiofrequency (RF) radiation has increased in recent years due to the rapid development of mobile communication and widespread use of mobile phone. Public concerns have raised about the possible health hazards of mobile phone radiation. Some epidemiological studies have indicated an association between mobile phone use and the risk of human cancers or non-cancer diseases while there are some adverse findings. Similarly, large amounts of in vivo and in vitro studies were conducted but contradictory data still remain in the literature. Therefore it has become difficult to determine the health effects of RF EMF, attributing to the inconsistent results. So we need to focus on the mechanism of interaction between RF EMF and organisms. DNA double-strand break ( DSB ) is the initiate signal of cell apoptosis in response to environmental stress, and can be used as a biomarker toevaluate the possible carcinogenic effect of RF EMF and analyze its underlining mechanism of action. Thus, we used γ-H2AX formation, an early indicator of DNA double-strand breaks, to study the DNA damage of ES cells after intermittently exposed (5 min on /10 min off) to 1800 MHz RF EMF at the average specific absorption rate (SAR) of 3 W/kg. For each sample, at least 60 cells were selected to measure the number of γ-H2AX foci. Cells were classified as positive when more than five γ-H2AX foci were detected. After comparing the positive cell rates between the exposure group and sham exposure group, we find that exposure to 3.0 W/kg RF EMF for 1 , 6, and 24 h all resulted in a higher ratio of positive cells than the sham exposure, but with no statistically significant difference ( p>0.05 ). To further analyze the effects of RF EMF on DNA damage, the percentage of cells bearing 0, 1-5, 6-10, or more than 10 γ-H2AX foci were calculated at the same time, and the data revealed that the percentage of cells had no statistically significant difference (p > 0.05) by comparing the cell ratio of different foci classes between the exposure group and sham exposure group after exposure for 1 , 6, or 24 h. Based on the current results, we concluded that 1800 MHz RF EMF at the SAR of 3.0 W/kg for 1, 6, 24 h does not induce DNA damage in mouse embryonic stem cells under current experimental conditions.更多还原