Ejaculated, density purified, human spermatozoa were exposed to 900 MHz GSM mobile phone radiation at two specific absorption rate levels (SAR 2.0 and 5.7 W/kg) and examined at various time points post exposure. Change in sperm mitochondrial membrane potential was analyzed using flow cytometry. Sperm motility was determined by computer assisted sperm analysis (CASA). There was no effect of 900MHz GSM radiation on mitochondrial membrane potential. This was also the case for all kinematic parameters assessed at SAR of 2.0 W/kg. However, two kinematic parameters (VSL and BCF) were statistically significantly altered after the exposure at SAR 5.7 W/kg. Effects seen cannot be ascribed to heating, as the temperature did not increase by more than 0.3ºC. A thorough investigation at lower SAR levels is required to determine the extent of the influence of RF-EMF on human sperm motility.

Abstract Ejaculated, density purified, human spermatozoa were exposed to pulsed 900 MHz GSM mobile phone radiation at two specific absorption rate levels (SAR 2.0 and 5.7 W/kg) and compared with controls over time. Change in sperm mitochondrial membrane potential was analysed using flow cytometry. Sperm motility was determined by computer assisted sperm analysis (CASA). There was no effect of pulsed 900 MHz GSM radiation on mitochondrial membrane potential. This was also the case for all kinematic parameters assessed at a SAR of 2.0 W/kg. However, over time, the two kinematic parameters straight line velocity (VSL) and beat-cross frequency (BCF) were significantly impaired (P<0.05) after the exposure at SAR 5.7 W/kg and no exposure by time interaction was present. This result should not be ascribed to thermal effects, due to the cooling methods employed in the RF chamber and temperature control within the incubator.

Several studies have highlighted the possibility that radio-frequency electromagnetic fields (RF-EMF) used in mobile phone technology could influence DNA integrity of male germ cells as well as sperm motility. Current knowledge concerning the influence of RF-EMF on male germ cells is extremely limited. In the present study the hypothesis that 900 MHz GSM radiation could induce the activation of stress response in human spermatozoa was investigated. Ejaculated, density purified, human spermatozoa from donors were exposed to 900 MHz GSM mobile phone radiation at specific absorption rate (SAR) levels of 2.0 and 5.7 W/kg and examined at various time points post exposure. Sperm motility and morphology were evaluated by computer-aided sperm analysis (CASA). The ability of RF-EMF exposed sperm to undergo the acrosome reaction was evaluated by flow cytometry. Sperm binding to the zona pellucida of human oocytes was determined by the hemi-zona (HZA) assay. Apoptotic markers, phosphatidylserine (PS) externalization, change in mitochondrial membrane potential (Δψm), reactive oxygen species (ROS) generation, caspase activation and DNA fragmentation were analysed using flow cytometry. Heat shock protein (Hsp) 27 and 70 expression and activity were analyzed using specific antibodies with flow cytometry and Western blot methods. Stress fibre stabilization (F-actin polymerization) was visualized using fluorescent dye labelled phalloidin. No effect was seen on kinematic parameters assessed at SAR 2.0 W/kg, however straight line velocity (VSL) and beat cross frequency (BCF) were significantly altered after exposure at SAR 5.7 W/kg. Sperm shrinkage (decrease in surface area) was observed at both exposure levels. RF-EMF did not influence exposed spermatozoa’s ability to undergo the acrosome reaction. A significant decrease in sperm-zona binding was observed at both exposure levels. RF radiation did not have an effect on any apoptotic markers. ROS generation increased significantly with an increase in SAR (5.7 W/kg). RF-EMF did not induce a stress response in exposed sperm (no activation of Hsp70 and 27 activity). These results cannot be ascribed to heating, as the temperature did not increase by more than 0.2 - 0.3ºC during exposure. The decrease in sperm-zona binding is the result of an alternative non-stress inducible pathway. This study should be replicated at lower SAR levels that would simulate the radiation absorption from carrying the cell phone in a pocket close to the testes. / Thesis (PhD (Reproductive Biology))--University of Pretoria, 2008. / Obstetrics and Gynaecology / unrestricted

We are somewhat surprised about the extent of the feedback that we received upon our publication [1], in terms of the not entirely new connection between mobile phone radiation, brain activity, and food intake, being previously explored by EEG, association studies, and animal experiments (as outlined in the introduction of our paper). Ten years ago, scientists found “alarming” evidence of a long-term association between mobile phone radiation and obesity in humans [2]. Specifically, we are perplexed by the partly emotional character of the discussion among our readers. However, back to the facts: We thank our scientific colleagues for their detailed analyses and considerations [3] regarding our study and are pleased to explain the open points for more clarity.