Medical/biological study (experimental study)

Assessment of genotoxic and cytotoxic hazards in brain and bone marrow cells of newborn rats exposed to extremely low-frequency magnetic field med./bio.

By: Rageh MM, El-Gebaly RH, El-Bialy NS

Published in: J Biomed Biotechnol 2012: 716023

Aim of study (acc. to author)

To examine the cytotoxic and genotoxic effects and the level of oxidative stress in the brain and bone marrow cells after an exposure to extremely low frequency magnetic fields of newborn rats.

Background/further details

Exposure or sham exposure started at an age of 10 days and lasted for 30 days. In total, 60 rats were examined. For the micronucleus test, comet assay and the histopathological examination, 10 rats per group (exposed/sham exposed) were used. Another 10 rats per group were used for the determination of the mitotic index and the last 10 rats per group for the evaluation of the oxidative stress.

Endpoint

genotoxicity/mutation: DNA strand breaks in brain cells; chromosome damage in bone marrow cells
cytotoxicity in brain and bone marrow cells; oxidative stress

Exposure

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

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: continuous for 24 h/day on 30 days	magnetic flux density: 0.5 mT (± 0.025 mT)

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Exposure duration	continuous for 24 h/day on 30 days

Exposure setup

Exposure source	solenoid
Chamber	40 cm x 25 cm x 20 cm plastic cage housing 30 young rats
Setup	solenoid constructed by winding 320 turns of insulated 0.8 mm copper wire round a 2 mm thick, 40 cm long copper cylinder with a diameter of 40 cm; cylinder earthed; cage placed in the center of the solenoid
Sham exposure	A sham exposure was conducted.
Additional info	field was switched off during cage cleaning

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	0.5 mT	-	measured	-	± 0.025 mT

Exposed system:

animal
rat/Wistar
whole body

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: DNA strand breaks in brain cells (comet assay); chromosome damage in bone marrow cells (micronucleus test, May-Grünwald-Giemsa staining, light microscopy))
cell viability/cell division/proliferation: mitotic index in bone marrow cells (Giemsa staining, light microscopy)
morphol./histopathol. changes: histopathological examinations of the brain (hematoxylin-eosin stain, light microscopy)
oxidative stress in brain: enzyme activity of the superoxide dismutase, level of glutathione, lipid peroxidation (amount of malondialdehyde) (spectrophotometry)

Investigated system:

isolated bio./chem. substance
intact cell/cell culture
tissue slices
brain homogenates

Investigated organ system:

Time of investigation:

after exposure

Main outcome of study (acc. to author)

In the exposed group, the enzyme activity of the superoxide dismutase and the lipid peroxidation were significantly increased compared to the sham exposed group. In the histopathological examination of the brain tissue, only slight differences were found between the sham exposed and exposed rats (mild degeneration in the glia, gliosis, vascular congestion).The DNA damage in the brain, as well as the mitotic index and the chromosome damage in the bone marrow cells were significantly increased in the exposed rats compared to the sham exposed rats.
The authors conclude that exposure to extremely low frequency magnetic fields could lead to cytotoxic and genotoxic damage, as well as to oxidative stress in the brain and bone marrow of newborn rats.

Study character:

medical/biological study
experimental study
full/main study

Teimori F et al. (2016): The effects of 30 mT electromagnetic fields on hippocampus cells of rats
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