Effects Of 1800 MHz Radiofrequency Electromagnetic Fields On DNA Damage In Mouse Embryonic Stem Cells

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.