Medical/biological study (experimental study)

Exposure to 60 Hz magnetic fields and proliferation of human astrocytoma cells in vitro med./bio.

By: Wei M, Guizzetti M, Yost M, Costa LG

Published in: Toxicol Appl Pharmacol 2000; 162 (3): 166-176

Aim of study (acc. to author)

This study was performed to investigate the effects of a 60 Hz sinusoidal magnetic field on the cell proliferation of human astrocytoma cells and rat cortical astrocytes in vitro.

Background/further details

Additionally, the role of the temperature, of chemical agonists (carbachol, tetradecanoylphorbol acetate induce DNA synthesis), and the protein kinase C inhibitor (GF 109203X) should be examined.
The experiments were done in triplicate and repeated at least three times.

Endpoint

cell viability/cell division/proliferation: cell proliferation

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: 3 - 72 h	magnetic flux density: 0.03 mT effective value magnetic flux density: 0.12 mT maximum

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	3 - 72 h

Exposure setup

Exposure source	coil(s)
Setup	double wrapped square four-coil Merritt system; 0.233 m-square bifiliar coils with 78, 33, 33, 78 turns; cell cultures placed inside the coils; MF perpendicular to plane of cell culture plates
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	0.03 mT	effective value	measured	-	-
magnetic flux density	0.12 mT	maximum	measured	-	-

Additional parameter details

background field (due to heating elements and other sources): 1.35 +/- 0.08 µT left side; 1.28 +/- 0.08 µT right side

Exposed system:

intact cell/cell culture
132-1N1 (human astrocytoma cell line) and normal rat cortical astrocytes

Methods Endpoint/measurement parameters/methodology

cell viability/cell division/proliferation: cell proliferation (DNA synthesis, ³H-thymidine incorporation, scintillation counter; BrdU incorporation, flow cytometry)

Investigated system:

intact cell/cell culture

Investigated organ system:

brain/CNS

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The magnetic field caused a time- and dose-dependent increase in proliferation of human astrocytoma cells, and strongly potentiated the effect of carbachol and tetradecanoylphorbol acetate. However, magnetic field had no effect on DNA synthesis of normal rat cortical astrocytes.
A 0.7 °C temperature increase was observed in the magnetic field (at 1.2 Gauss) exposed and sham exposed medium, however, ³H-thymidine incorporation caused by magnetic field exposure was significantly higher than that induced by sham exposure.
The protein kinase C inhibitor, and arteficial down-regulation of protein kinase C inhibited the effect of magnetic field ³H-thymidine incorporation.
The results indicate that magnetic field can increase the proliferation of human astrocytoma cells and strongly potentiate the proliferation supporting effects of carbachol and tetradecanoylphorbol acetate, probably by the involvement of proteinkinase C.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

National Institute of Environmental Health Sciences (NIEHS), North Carolina, USA

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