Medical/biological study (experimental study)

Clastogenicity and aneuploidy in newborn and adult mice exposed to 50 Hz magnetic fields med./bio.

By: Udroiu I, Cristaldi M, Ieradi LA, Bedini A, Giuliani L, Tanzarella C

Published in: Int J Radiat Biol 2006; 82 (8): 561-567

Aim of study (acc. to author)

To detect possible clastogenic and aneugenic properties of a 50 Hz magnetic field in newborn and adult mice.

Background/further details

Liver and peripheral blood samples (erythrocytes) from newborn mice exposed to an extremely low frequency magnetic field during the whole intrauterine life (21 days), and bone marrow and peripheral blood samples from adult mice exposed to the same magnetic field for the same period were investigated.
Micronuclei are produced after chromosome breakage (clastogenic damage, leads to a micronucleus with a chromosome fragment) or spindle disturbance (aneugenic damage, leads to micronucleus with a whole chromosome).
Positive control was carried out with X-rays (3 Gy).

Endpoint

genotoxicity/mutation: clastogenic and aneugenic effects

Exposure

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 24 h/day for 21 days	magnetic flux density: 650 µT effective value (at the centre of the solenoid)

General information

The experiment was performed with 4 groups: a) 15 adult mice b) 36 newborn mice from 4 pregnant mice which were exposed during pregnancy and three days after birth c) a control group of 15 adult mice which were not exposed d) a positiv control group with 6 adult mice which were exposed to X-rays

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	24 h/day for 21 days

Exposure setup

Exposure source	solenoid
Chamber	the solenoid was 0.8 m in length and 0.13 m in radius, with 552 turns of 2.5 mm² copper wire. The solenoid was not shielded.
Additional info	A control group of another 15 mice was kept un-exposed for 21 days. Positive control was carried out exposing 6 adult mice to X-rays.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	650 µT	effective value	unspecified	-	at the centre of the solenoid

Exposed system:

animal
mouse/CD-1 Swiss
whole body

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: clastogenic and aneugenic effects (micronucleus assay with CREST antibody (to detect the presence or absence of centromere proteins); immunofluorescence)

Investigated system:

DNA/RNA
intact cell/cell culture

Investigated organ system:

immune system
liver, blood, bone marrow

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Data of newborn mice showed a significant increase in micronuclei frequencies. In absolute terms, most of the induced micronuclei were CREST-negative (i.e. formed by a chromosome fragment). However, in relative terms, extremely low frequency exposure caused a two-fold increase in CREST-negative micronuclei and a four-fold increase in CREST-positive micronuclei (i.e. formed by a whole chromosome).
No significant effect was recorded on exposed adult mice.
In conclusion, further studies are needed to investigate the possible link between electromagnetic fields and aneuploidy, because the importance of aneuploidy in relation to carcinogenesis.

Study character:

medical/biological study
experimental study
full/main study
blind study

Study funded by

Istituto Superiore per la Prevenzione e la Sicurezza del Lavoro (ISPESL; National Institute for Occupational Safety and Prevention), Italy

Udroiu I et al. (2015): Genotoxicity induced by foetal and infant exposure to magnetic fields and modulation of ionising radiation effects
Miyakoshi Y et al. (2012): Tempol suppresses micronuclei formation in astrocytes of newborn rats exposed to 50-Hz, 10-mT electromagnetic fields under bleomycin administration
Mariucci G et al. (2010): Brain DNA damage and 70-kDa heat shock protein expression in CD1 mice exposed to extremely low frequency magnetic fields
Okudan N et al. (2010): Effects of long-term 50 Hz magnetic field exposure on the micro nucleated polychromatic erythrocyte and blood lymphocyte frequency and argyrophilic nucleolar organizer regions in lymphocytes of mice
McNamee JP et al. (2005): Evaluating DNA damage in rodent brain after acute 60 Hz magnetic-field exposure
Winker R et al. (2005): Chromosomal damage in human diploid fibroblasts by intermittent exposure to extremely low-frequency electromagnetic fields
Vijayalaxmi et al. (2005): Controversial cytogenetic observations in mammalian somatic cells exposed to extremely low frequency electromagnetic radiation: a review and future research recommendations
Yokus B et al. (2005): Oxidative DNA damage in rats exposed to extremely low frequency electro magnetic fields
Wolf FI et al. (2005): 50-Hz extremely low frequency electromagnetic fields enhance cell proliferation and DNA damage: possible involvement of a redox mechanism
Stronati L et al. (2004): Absence of genotoxicity in human blood cells exposed to 50 Hz magnetic fields as assessed by comet assay, chromosome aberration, micronucleus, and sister chromatid exchange analyses
Testa A et al. (2004): Evaluation of genotoxic effect of low level 50 Hz magnetic fields on human blood cells using different cytogenetic assays
Ding GR et al. (2003): Induction of kinetochore-positive and kinetochore-negative micronuclei in CHO cells by ELF magnetic fields and/or X-rays
Ivancsits S et al. (2003): Age-related effects on induction of DNA strand breaks by intermittent exposure to electromagnetic fields
Ivancsits S et al. (2003): Intermittent extremely low frequency electromagnetic fields cause DNA damage in a dose-dependent way
Verheyen GR et al. (2003): Effect of coexposure to 50 Hz magnetic fields and an aneugen on human lymphocytes, determined by the cytokinesis block micronucleus assay
Ivancsits S et al. (2002): Induction of DNA strand breaks by intermittent exposure to extremely-low-frequency electromagnetic fields in human diploid fibroblasts
McNamee JP et al. (2002): DNA damage and apoptosis in the immature mouse cerebellum after acute exposure to a 1 mT, 60 Hz magnetic field
Abramsson-Zetterberg L et al. (2001): Extended exposure of adult and fetal mice to 50 Hz magnetic field does not increase the incidence of micronuclei in erythrocytes
Yaguchi H et al. (2000): Increased chromatid-type chromosomal aberrations in mouse m5S cells exposed to power-line frequency magnetic fields
Svedenstal BM et al. (1999): DNA damage, cell kinetics and ODC activities studied in CBA mice exposed to electromagnetic fields generated by transmission lines
Svedenstal BM et al. (1999): DNA damage induced in brain cells of CBA mice exposed to magnetic fields
Lai H et al. (1997): Acute exposure to a 60 Hz magnetic field increases DNA strand breaks in rat brain cells
Mailhes JB et al. (1997): Electromagnetic fields enhance chemically-induced hyperploidy in mammalian oocytes
Lai H et al. (1997): Melatonin and N-tert-butyl-alpha-phenylnitrone block 60-Hz magnetic field-induced DNA single and double strand breaks in rat brain cells