Medical/biological study (experimental study)

Analysis of DNA fragmentation in mouse embryos exposed to an extremely low-frequency electromagnetic field med./bio.

By: Borhani N, Rajaei F, Salehi Z, Javadi A

Published in: Electromagn Biol Med 2011; 30 (4): 246-252

Aim of study (acc. to author)

To study the possible effects of electromagnetic field exposure on DNA fragmentation in the blastomeres of mouse blastocysts.

Background/further details

80 female mice were divided into two groups of 40 animals each: 1) control group and 2) exposure group. After the 8^th day of exposure, the female mice in both groups were superovulated (with injections of gonadotropin) and then mated overnight. At approximately four days after mating blastocysts were obtained by flushing the uterus horns. 50 blastocysts were obtained from the controls and 60 blastocysts from the exposed group.

Endpoint

effects on embryo/fetus: cell death (DNA fragmentation) in blastocysts
effects on the reproductive system: fertility of female mice

Exposure

- 50 Hz
- 50/60 Hz
- magnetic field
- low frequency

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: continuous for 4 h/day, 6 days/week for 2 weeks	magnetic flux density: 0.5 mT

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Exposure duration	continuous for 4 h/day, 6 days/week for 2 weeks

Exposure setup

Exposure source	Helmholtz coils
Setup	pair of 30 cm x 30 cm square-shaped Helmholtz coils mounted in two frames; each coil with 1000 turns of copper wire; 27 cm x 21 cm x 14 cm cage with five animals placed on a platform between the coils; exposure system placed on a laboratory non-metallic table
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	0.5 mT	-	calibration	-	-

Exposed system:

animal
mouse/NMRI
whole body

Methods Endpoint/measurement parameters/methodology

effects on embryo/fetus: cell death (DNA fragmentation) in blastocysts (TUNEL assay)
effects on the reproductive system: fertility: number of blastocysts, number of pregnant mice, number of blastomeres per blastocyst

Investigated system:

blastocysts

Investigated organ system:

reproductive system

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The data showed that the mean number of blastocysts was significantly decreased in the exposed group compared with the control group. The DNA fragmentation index was significantly increased in the exposed group compared with the control. However, there was no significant difference in the mean numbers of blastomeres and numbers of pregnant mice between the exposed and control group.
The findings indicate that the electromagnetic field exposure in preimplantation stage could have detrimental effects on female mouse fertility and embryo development by decreasing the number of blastocysts and increasing the blastocysts DNA fragmentation.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Qazvin University of Medical Sciences, Iran

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