Effects of in vivo Electromagnetic Fields exposure of swine oviduct on fertilization outcome

All living beings are continuously exposed to different kinds of non ionizing radiations, either of natural origin or from human technological activity, ranging from static magnetic fields to radiofrequency fields. We focused our attention on Extremely low frequency electromagnetic fields (ELF-EMF), originating in electricity transport by power lines, that in Europe have a 50Hz frequency and in USA 60Hz. General population in houses and in shopping centers, schools and hospital, and workers in specific workplaces are always exposed to these fields. ELF-EMFs are classified as possible carcinogens (class 2b) by IARC [1] but data on their possible negative effect on reproduction are still not complete. This led to the need of knowing more about this exposure and of understanding its effects on living beings. Previous studies demonstrated that in vivo exposure of swine spermatozoa to a sinusoidal wave (intensity 1 mT, frequency 50 Hz), negatively affects sperm function, reducing the in vitro fertilization rate. Moreover, direct exposure of oviducts to fields ≥ 0.75 mT without spermatozoa led to negative effects on early embryo development, suggesting a decrease in the embryo cleavage compared to sham exposed [2]. The main aim of the study is the evaluation of in vivo effects of the exposure to ELF-EMF, in particular on the physiology of the oviduct and on fertilization outcome. The experimental protocol has been approved by our Inter-University Ethical Committee for Animal Experimentation (CEISA) prot.43/2011/CEISA/PROG/25. To assess the in vivo effects of the exposure of swine oviduct to ELF-EMF field, a validated protocol was adopted [2]. The estrus cycle was promoted on 3 prepubertal guilts of 91.1 ± 3.1 Kg: the follicular growth was stimulated by injection of IM 1250 UI eCG (Folligon, Intervet, MI) and the ovulation was induced 64h later with 750 UI eCG (Corulon, Intervet, MI). Then, we compared oviducts exposed for 1h to the ELF-EMF (intensity of 0,75 mT, frequency of 50 Hz, sinusoidal waveform) and successively surgically inseminated with the contro-lateral non exposed oviduct (sham). Twelve hours after the estimated time of fertilization the fertilized oocytes and were collected by flushing the oviducts. Gametes were fixed and observed with Lacmoid staining, to observe oocytes morphology, the percentage of fertilized oocytes, and the polyspermy rate. It was found that oocytes morphology was unaffected; the ELF-EMF exposure determines a significative decrease in the fertilization rate of oocytes (93.3±8.2% sham vs 64.6±10.2% exposed, p<0.05) and polispermy rate (60.3±3.8% sham vs 39.2±6.8% exposed, p<0.01) , while the number of spermatozoa/polispermic oocytes remained unaffected (5.7±0.6% sham vs 5.3±1.5% exposed, p>0.05). So we can confirm that in vivo exposure to an ELF-EMF could negatively affect the fertility outcome, either in terms of oocytes fertilized and on polyspermy rate. Further studies are needed to completely understand the possible interaction between Extremely low frequency electromagnetic fields and living beings, and in particular on reproductive functions. [1] IARC, http://monographs.iarc.fr/ENG/Classification/. [2] Bernabò N, Tettamanti E, Russo V, Martelli A, Turriani M, Mattoli M, Barboni B. Extremely low frequency electromagnetic field exposure affects fertilization outcome in swine animal model. Theriogenology. 2010 Jun;73(9):1293-305. doi: 10.1016/j.theriogenology.2009.12.010.