Study type: Medical/biological study (experimental study)

Lack of a co-promotion effect of 60 Hz rotating magnetic fields on N-ethyl-N-nitrosourea induced neurogenic tumors in F344 rats. med./bio.

Published in: Bioelectromagnetics 2008; 29 (7): 539-548

Aim of study (acc. to author)

To study the possible effect of 60 Hz magnetic fields as promoters of brain tumors initiated by ethylnitrosourea (ENU) in rats.

Background/further details

120 mated rats were divided into six different groups and exposed in utero on day 18 of gestation to a single intravenous dose of either saline (control group, group I), or ENU (10 mg/kg; groups II-VI). A total of 480 offspring was used. The offspring in group II were given no further treatment while the offspring in groups III-VI were exposed to four different intensities of magnetic fields including sham exposure (from the age of 4 weeks to the age of 32 or 42 weeks).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: continuous for 21 h/day from the age of 4 weeks to the age of 32 weeks or 42 weeks

General information

animals were divided into 6 groups: i) exposure in utero on day 18 of gestation to a single, intravenouse dose of saline ii)exposure in utero on day 18 of gestation to a single, intravenouse dose of ENU 10 mg/kg iii) exposure in utero on day 18 of gestation to a single, intravenouse dose of ENU 10 mg/kg + sham EMF exposure iv) exposure in utero on day 18 of gestation to a single, intravenouse dose of ENU 10 mg/kg + exposure to 5 µT v) exposure in utero on day 18 of gestation to a single, intravenouse dose of ENU 10 mg/kg + exposure to 83.3 µT vi) exposure in utero on day 18 of gestation to a single, intravenouse dose of ENU 10 mg/kg + exposure to 500 µT

Exposure 1

Main characteristics
Frequency 60 Hz
Type
Exposure duration continuous for 21 h/day from the age of 4 weeks to the age of 32 weeks or 42 weeks
Additional info rotating magnetic field
Exposure setup
Exposure source
Setup four square coils
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 5 µT - calculated - -
magnetic flux density 83.3 µT - calculated - -
magnetic flux density 500 µT - calculated - -

Reference articles

  • Chung MK et al. (2004): Lack of adverse effects in pregnant/lactating female rats and their offspring following pre- and postnatal exposure to ELF magnetic fields.
  • Chung MK et al. (2003): Developmental toxicity evaluation of ELF magnetic fields in Sprague-Dawley rats.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

Neurogenic tumors were found in all the ENU-treated groups. The tumor incidence of the ENU group at 32nd and 42nd week necropsy was higher than that of the control group.
However, there were no differences in the tumor incidence between the sham exposure group and "ENU + magnetic field" exposure groups.
In conclusion, there was no evidence that exposure of offspring to 60 Hz at magnetic field strengths up to 500 µT promoted ENU-initiated brain tumors in rats.

Study character:

Study funded by

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