Medical/biological study (experimental study)

Pulsating electromagnetic field stimulation prevents cell death of puromycin treated U937 cell line med./bio.

By: Kaszuba-Zwoinska J, Wojcik K, Bereta M, Ziomber A, Pierzchalski P, Rokita E, Marcinkiewicz J, Zaraska W, Thor P

Published in: J Physiol Pharmacol 2010; 61 (2): 201-205

Aim of study (acc. to author)

To study whether pulsating electromagnetic field (PEMF) can affect cell death of a cancer cell line.

Background/further details

Different cell densities were used and exposed (from 1x10⁶ cells/ml through 0.5, 0.25, 0.125 to 0.062 x10⁶ cells/ml). To induce cell death a high dose of puromycin 100 µg/ml (a antitumor drug) was added to the cell culture at a cell density of 0.25 x10⁶ cells/ml (simultaneously during the first PEMF exposure cycle or during all three PEMF exposures). Cells were investigated four days after the exposures.

Endpoint

cell viability/cell division/proliferation: cell death

Exposure

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: three times 3 hr with 24 hr intervals	magnetic flux density: 45 mT (+/- 5 mT)

General information

cells were co-exposed to 0, 1 or 3 doses of puromycin

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	pulsed
Exposure duration	three times 3 hr with 24 hr intervals

Exposure setup

Exposure source	generator
Setup	plate with cells placed in the generator pocket

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	45 mT	-	-	-	+/- 5 mT

Exposed system:

intact cell/cell culture
U937 (human leukemic monocyte cell line)

Methods Endpoint/measurement parameters/methodology

cell viability/cell division/proliferation: cell death, apoptosis, necrosis (allophycocyanin labeled annexin V staining (annexin V staining alone for apoptosis) and 7-amino-actinomycin D staining (together with annexin V for necrosis determination)); flow cytometry

Investigated system:

intact cell/cell culture

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The data showed that higher initial cell densities increased cell death in cultures of U937 cells. The PEMF exposure further decreased the amount of cells only at higher cell densities and induced apoptosis (i.e. increased the amount of annexin V positive cells). The PEMF exposure potentiated the cell density-induced cell death through both apoptosis and necrosis. The strongest influence of PEMF exposure was found for cell densities of 1 x 10⁶ cells/ml and 0.5 x 10⁶ cells/ml.
To eliminate the cell density effect on cell death, for the subsequent experiments with puromycin a cell density of 0.25 x 10⁶ cells/ml was used. Co-exposure of three doses of puromycin and PEMF resulted in a decrease of apoptosis by 24.7% and necrosis by 13%.
In conclusion, PEMF exposure protected U937 cells against puromycin-induced cell death. The effects of PEMF exposure on the U937 cell line depend on cell density.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

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