Chick embryo development can be irreversibly altered by early exposure to weak extremely-low-frequency magnetic fields.
Several reports have shown that weak, extremely-low-frequency (ELF), pulsed magnetic fields (PMFs) can adversely affect the early embryonic development of the chick. In this study, freshly fertilized chicken eggs were exposed during the first 48 h of postlaying incubation to PMFs with 100 Hz repetition rate, 1.0 microT peak-to-peak amplitude, and 500 microseconds pulse duration. Two different pulse waveforms were used, having rise and fall times of 85 microseconds (PMF-A) or 2.1 microseconds (PMF-B). It has been reported that, with 2 day exposure, these fields significantly increase the proportion of developmental abnormalities. In the present study, following exposure, the eggs were allowed to incubate for an additional 9 days in the absence of the PMFs. The embryos were taken out of the eggs and studied blind. Each of the two PMF-exposed groups showed an excess in the percentage of developmental anomalies compared with the respective sham-exposed samples. This excess of anomalies was not significant for the PMF-A-treated embryos (P = 0.173), whereas it was significant for the PMF-B-exposed group (P = 0.007), which showed a particularly high rate of early embryonic death. These results reveal that PMFs can induce irreversible developmental alterations and confirm that the pulse waveform can be a determinant factor in the embryonic response to ELF magnetic fields. The data also validate previous work based on the study of PMFs' effects at day 2 of embryonic development under field exposure.
Ubeda
A
A
Departamento de Investigación, Hospital Ramón y Cajal, Madrid, Spain.
Trillo
M A
MA
Chacón
L
L
Blanco
M J
MJ
Leal
J
J
D000016:Abnormalities, Radiation-Induced / Q000209:etiology*; D000818:Animals; D001842:Bone and Bones / Q000002:abnormalities / Q000196:embryology / Q000528:radiation effects; D002642:Chick Embryo; D000013:Congenital Abnormalities / Q000209:etiology*; D003643:Death; D004574:Electromagnetic Fields / Q000009:adverse effects*; D006358:Hot Temperature; D008280:Magnetics / Q000009:adverse effects* / Q000145:classification; D015203:Reproducibility of Results; D016037:Single-Blind Method; D013997:Time Factors