Effects of Radiofrequency Exposure and Co-Exposure on Human Lymphocytes: The Influence of Signal Modulation and Bandwidth

The occurrence of modulation-specific effects after co-exposures to radio-frequency (RF) and other agents has been discussed in the literature. In this paper, the influence of modulation and bandwidth in eliciting the DNA damage of RF alone and in combination with mitomycin-C (MMC) is analyzed in human lymphocytes. Blood cultures from healthy donors were exposed to 1950 MHz, and continuous wave (CW), wideband direct-sequence code division multiple access (WCDMA, 4.5 MHz bandwidth), and additive white Gaussian noise (AWGN, 9 MHz bandwidth) signals were considered. For each signal, specific absorption rate (SAR) values of 0.15, 0.3, 0.6, 1.25 W/kg were tested. RF exposure alone never induced DNA damage in the micronucleus assay. When RF exposure was followed by MMC treatment, the effect depended on modulation and bandwidth. CW exposure never altered the MMC induced DNA damage, while such damage was reduced when either signals WCDMA at 0.3 W/kg SAR or AWGN at 0.15 and 0.3 W/kg were applied. These results indicate the influence of modulation for the occurrence of the protective effect, with a relation between the bandwidth and the power absorbed by samples. If confirmed in vivo, clinical applications using modulated RF signals could be devised to protect cells from side effects of therapeutic treatments.