Medical/biological study (experimental study)

Developmental effects of low frequency magnetic fields on P19-derived neuronal cells med./bio.

By: Saito A, Takayama Y, Moriguchi H, Kotani K, Jimbo Y

Published in: 2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Minneapolis, MN, USA. IEEE, 2009: pp. 5942-5945; ISBN 978-1-4244-3296-7

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Aim of study (acc. to author)

The aim of this study was to investigate the effect of extremely low frequency magnetic fields (1 mT and 10 mT) on the neuronal differentiation process (cell morphology and electrical activity) of an embryonal carcinoma stem cell model.

Background/further details

The extremely low frequency magnetic field exposure was applied to embryoid bodies (aggregates of cells derived from embryonic stem cells) formed at induction of neuronal cell differentiation process and the effects of exposure were evaluated after neuronal differentiation.
The spontaneous electrical activities of neuronal cells are generated during the differentiation process of neuronal networks, and these activities show clearly different behavior according to differentiation periods.

Endpoint

cell function: developmental neuronal activity (electrical activity)
morphol./histopathol. changes: neuronal and glial cell differentiation, cell morphology

Exposure

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: during cell differentiation	magnetic flux density: 1 mT magnetic flux density: 10 mT

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	during cell differentiation

Exposure setup

Exposure source	Helmholtz coils
Setup	the Helmholtz coils was set in a CO₂ incubator with constant temperature

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	1 mT	-	measured	-	-
magnetic flux density	10 mT	-	measured	-	-

Exposed system:

intact cell/cell culture
P19 cells (mouse embryonal carcinoma cells)

Methods Endpoint/measurement parameters/methodology

cell function: developmental neuronal activity, electrical activity (spike frequency, action potential, microelectrode array)
cell viability/cell division/proliferation: cell death (Trypan blue exclusion assay)
morphol./histopathol. changes: neuronal and glial cell differentiation (percentage of neurons and astrocytes: expression of glial fibrillary acidic protein (as glial marker) and microtubule-associated protein 2 (as neuronal marker); immunohistochemistry, phase contrast microscopy), cell morphology (formation and size of embryoid bodies)

Investigated system:

intact cell/cell culture

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The data showed that the size of embryoid bodies exposed to 10 mT extremely low frequency magnetic fields was significantly decreased compared to non-exposed embryoid bodies. The cell differentiation rate of neuronal cells and functional neuronal network activities were also significantly modulated by exposure to 10 mT magnetic field: The percentage of MAP2-positive cells was increased and GFAP positive cells was decreased at 14 and 21 days after plating. Additionally, the spike frequencies and the active electrodes (i.e. electrodes that detected action potentials) of the spontaneous electrical activity in this period were also increased. However, these effects were not found in 1 mT exposed cells.
In conclusion, exposure of embryoid bodies at the induction of differentiation period to 10 mT extremely low frequency magnetic fields had a functional influence on the neuronal differentiation process.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

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