Mouse early embryos obtained by natural breeding or in vitro fertilization display a differential sensitivity to extremely low-frequency electromagnetic fields.
We have investigated the sensitivity of pre-implantation embryos obtained by natural breeding (NB) or in vitro fertilization (IVF) to extremely low-frequency magnetic fields (ELF-MF). Fertilized eggs obtained by NB were removed from mothers 12h after mating and cultured in vitro for 5 days under continuous ELF-MF exposure (constant strength of 50Hz and various intensities, i.e. 60, 120 and 220 microT). Alternatively, zygotes obtained by IVF were subjected to ELF-MF exposure (50Hz, 60 microT), starting 12h after IVF for 5 days. We found that ELF-MF exposure causes a small yet significant (P<0.05) decrease in the survival rate of NB-derived embryos at the latest stages of pre-implantation development, i.e. the eight cell-to-blastocyst transition. In embryos exposed to the highest field intensity (220 microT), the effect became apparent somewhat earlier. When IVF-derived embryos were exposed to ELF-MF, the reduction in the rate of embryo survival was more pronounced and the difference from controls was more significant (P<0.01). Moreover, the decreased survival rate in IVF embryos became apparent as early as the first cleavage and persisted throughout pre-implantation. These results suggest that IVF-derived embryos are more sensitive than NB-generated embryos to ELF-MF, and that this sensitivity occurs earlier in development.
Beraldi
Rosanna
R
Istituto Superiore di Sanità, Rome, Italy.
Sciamanna
Ilaria
I
Mangiacasale
Rosamaria
R
Lorenzini
Rodolfo
R
Spadafora
Corrado
C
D000818:Animals; D001755:Blastocyst / Q000528:radiation effects*; D001947:Breeding; D000013:Congenital Abnormalities / Q000209:etiology; D004307:Dose-Response Relationship, Radiation; D004574:Electromagnetic Fields / Q000009:adverse effects*; D020964:Embryo Loss; D005260:Female; D005307:Fertilization in Vitro; D008297:Male; D051379:Mice; D009924:Organ Culture Techniques; D011247:Pregnancy; D011833:Radiation Injuries, Experimental; D015053:Zygote / Q000528:radiation effects