The use of mobile phones and other devices generating electromagnetic fields (EMF) is increasing rapidly. The health consequences for humans and the environment cannot be foreseen at this time. However, there is increasing evidence that especially oxidative stress caused by reactive oxygen species (ROS) and free radicals is generated by electromagnetic fields. The exact mechanism as to how mobile phone radiation affects biological systems has yet to be determined. Mobile communication devices emit radiation in the microwave range. 3G devices of the Universal Telecommunications System (UMTS) operate in Germany in the frequency bands 1920–1980 MHz and 2110–2170 MHz. Male sex organs in particular are very sensitive to oxidative stress. Sperm cell membranes are rich in polyunsaturated fatty acids, which are peroxidized by ROS and free radicals. In addition, the body’s antioxidant defense system is fairly weak in sperm. The aim of the present study was to investigate different sperm parameters, ROS, lipid peroxidation, testicular morphology and mitochondrial activity in rats after 3G mobile phone exposure. These “power plants,” the mitochondria, play an important role in cell energy production. Since they are involved in the respiratory chain und thus in intracellular oxygen metabolism, they also generate ROS under physiological conditions.
Adult male rats were selected as experimental animals to be exposed to 3G radio-frequency radiation. 16 rats were divided into two groups (control group and exposure group). The exposure group was exposed to 3G radio-frequency radiation for 2 hours per day for 45 days. A mobile phone operating in the UMTS band (1915 MHz) served as the radiation source. The estimated SAR value was 0.26 W/kg. After exposure, the animals were sacrificed and their testicles removed. The sperm morphology (microscopic), sperm survival (eosin staining), membrane integrity (hypo-osmotic swelling test), mitochondrial sperm activity (DAB test), ROS level (chemiluminescence test), lipid peroxidation (MDA test) and histopathology were analyzed.
First, testicles of both groups were weighed. The testicular weight of the exposure group was statistically significantly lower than that of the control group. However, there was no difference in the weight of the epididymis (location where spermatogenesis takes place). Subsequently, different sperm parameters were evaluated. Sperm count and survival were significantly reduced in the exposure group compared to the control group. In addition, the scientists found evidence that the cell membrane of sperm in exposed animals showed signs of damage more frequently. The morphological analysis of sperm heads revealed no differences between both groups although they described variations in size of the spermatic ducts, disorders of the germ layer and a reduced number of sperm cells after exposure. The analysis of ROS levels showed a significant increase in the exposure group compared to the control group. Increased lipid peroxidation was induced by exposure as well. Due to this disturbance of the redox balance, the authors also investigated the activity of mitochondria. The number of fully active mitochondria was significantly reduced in the exposed group, while the number of partially active and fully inactive mitochondria was increased.
The authors conclude from their data that the male reproductive system is impaired by 3G radio-frequency radiation. The triggered oxidative stress seems to alter the testicular structure and sperm parameters (sperm count, morphology, survival and membrane integrity). Moreover, a reduced mitochondrial activity may indicate a reduced sperm motility.
Editor’s note: Although the study uses interesting methods and can demonstrate increased oxidative stress as well as decreased sperm quality caused by EMFs, there are a number of problems with the study design. For example, the control group was not sham-exposed. Thus, the animals escaped the stressful procedure of being removed from their cage and transferred to the exposure apparatus (of course, without switching it on). In addition, histopathological examinations of the sperm, germ layer and number of sperm cells were not quantified.
Only images confirming the authors’ statements have been published, which are hard to verify without quantification.