Exposure to 50 Hz magnetic field at 100 µT exert no DNA damage in cardiomyocytes

The effects of exposure to magnetic fields (MFs) at city electric frequencies (50-60 Hz) on carcinogenicity are still in debate. Besides, whether exposure to MFs affects the heart is also a debated issue. This study aimed to determine whether exposure to extremely low frequency magnetic fields (ELF-MFs) induced DNA damage in cardiomyocytes both in vitro and in vivo. Human ventricular cardiomyocytes were exposed to 50 Hz ELF-MF at 100 µT for 1 hr continuously or 75 min intermittently. The effects of the treatments were evaluated by DNA damage, redox status changes, and relative signal molecular expression. Moreover, ten male Sprague-Dawley rats were exposed to a 50 Hz MF at 100 µT for 7 days, while another 10 rats were sham exposed. The protein levels of p53 and Hsp70 in heart tissue were analyzed by western blot. The results showed that exposure to ELF-MF did not induce DNA damage, cell cycle distribution change, or increased ROS level. No significant differences were detected in p53 and Hsp70 expression level between the ELF-MF and sham-exposure groups both in vitro and in vivo. All these data indicated that MFs at power-frequency may not cause DNA damage in cardiomyocyte.