Effect of Intermittent ELF MF on Umbilical Cord Blood Lymphocytes

Abstract

Having recently shown that intermittent extremely low frequency (ELF) magnetic fields (MF) inhibited proliferation of a cancer cell line, we wondered whether such fields could have some effect on normal blood cells. In order to test this, we exposed umbilical cord blood lymphocytes (UCBL) to MF with the same waveform (triangular, 7.8 Hz) and intermittence (250 s ON / 250 s OFF) during 48 h and 72 h, testing six amplitudes (between 6 µT and 24 µT) simultaneously in each experiment. We assessed percentages of viable, early apoptotic (EA) and late apoptotic/necrotic (LAN) cells, reactive oxygen species (ROS) production, and DNA double strand breaks (DSB) indicated by formation of 53BP1 and gamma-H2AX foci and their co-localization. No effect on DSB or ROS production was found for either exposure duration. However, a statistically significant decrease in viability occurred for field amplitudes below 17 µT after the 72-h exposure. It is remarkable that the effect appeared for field intensities below a certain threshold, strongly suggesting an amplitude window and thus the need of screening for different amplitudes of the same MF waveform.