De Iuliis, G. N.; Newey, R. J.; King, B. V., and Aitken, R. J. Mobile phone radiation induces reactive oxygen species production and DNA damage in human spermatozoa in vitro. PLoS One. 2009; 4(7):e6446.
Male infertility is a common human condition related in most cases to functional deficiencies in spermatozoa. Though the causes of such deficiencies are largely unknown, one factor is the quality of the sperm DNA. Research has recently been focused on environmental factors that can potentially contribute to the etiology of DNA damage in human spermatozoa, including exposure to radiofrequency electromagnetic radiation (RF-EMR) from mobile phones. It is important to determine if exposure to RF-EMR can induce DNA damage and, if so, to elucidate the cellular mechanism. It has been suggested that oxidative stress can be a key factor involved in the mechanism of DNA damage by RF-EMR. It is known that human spermatozoa are particularly vulnerable to oxidative stress.
To study responses of human spermatozoa to exposures to RF-EMR over a wide range of SAR values, including SAR values characteristic of mobile phone emissions, in order to elucidate underlying pathophysiological mechanisms.
Purified human spermatozoa from 22 donors with no known male reproductive pathologies were exposed for 16 hours to 1.8 GHz RF-EMR at SAR values from 0.4 W/kg to 27.5 W/kg. Motility and vitality were measured prior to and after the exposure. Reactive oxygen species (ROS) and DNA damage assays were performed on both the exposed cells and on the respective controls after incubation.
Exposure to RF-EMR resulted in a dose-dependent decline in vitality and motility of the cells, activation of ROS production by the whole cell and by the mitochondria, an increase in the amount of oxidative DNA damage and DNA fragmentation. Significant reduction in vitality and motility and a significant increase in ROS positive cells were observed after exposure at SAR of 1.0 W/kg. A significant increase in the expression of a marker for oxidative damage to sperm DNA was apparent at SAR values <5 W/kg, and an increase in DNA strand breaks at SAR of 2.8 W/kg. There was a significant correlation between the SAR level, the expression of the marker of oxidative DNA damage, and DNA fragmentation.
Interpretation and Conclusion
The authors recognize that, because their study was conducted on spermatozoa in vitro, its results cannot be directly transferred to situations with exposure in vivo. However, because effects on sperm quality have previously been observed in whole animal experiments and in epidemiological studies of human subjects, these findings are biologically and clinically relevant. Thus, this study demonstrates that RF-EMR in power density and frequency range of mobile phones can damage sperm function via mechanisms that involve oxidative stress. The authors recommend that men of reproductive age do not keep their phones in receiving mode below waist level.