Study type: Medical/biological study (experimental study)

Protective Effects of Low-Frequency Magnetic Fields on Cardiomyocytes from Ischemia Reperfusion Injury via ROS and NO/ONOO(-) med./bio.

By: Ma S, Zhang Z, Yi F, Wang Y, Zhang X, Li X, Yuan Y, Cao F
Published in: Oxid Med Cell Longev 2013: 529173
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Aim of study (acc. to author)

To investigate whether low frequency magnetic fields can protect cardiac rat myocytes from ischemia re-perfusion injury and to study its underlying molecular mechanisms.

Background/further details

Reconstitution of the blood perfusion in the heart (re-perfusion) can be necessary in the treatment of the acute coronary syndrom (for example myocardial infarction). However, re-perfusion strategies may result in so called "re-perfusion injuries". Those damages are associated with the overproduction of reactive oxygen species. Low frequency pulsed magnetic fields are suggested to prevent the overproduction of reactive oxygen species. Here, the hypoxia/reoxygenation treatment simulates the re-perfusion.
Several groups were examined: 1.) control group, 2.) hypoxia/reoxygenation treatment, 3.) 8 different magnetic field exposure groups. Cell cultures were exposed to the magnetic field for 1, 3 or 5 hours before or after the hypoxia/reoxygenation treatment.
For the examination of the generation reactive oxygen species, positive controls were performed. For the generation of nitric oxide, the enzyme activity of the endothelial nitric oxide synthase was inhibited with NG-nitroarginine methyl ester. For the generation of superoxide, hydrogen peroxide was used as a positive control.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 15 Hz
Exposure duration: 1, 3 or 5 hours
Exposure 2: 20 Hz
Exposure duration: 1, 3 or 5 hours
Exposure 3: 15 Hz
Exposure duration: 1, 3 or 5 hours
Exposure 4: 20 Hz
Exposure duration: 1, 3 or 5 hours
Exposure 5: 15 Hz
Exposure duration: 1, 3 or 5 hours
Exposure 6: 20 Hz
Exposure duration: 1, 3 or 5 hours
Exposure 7: 15 Hz
Exposure duration: 1, 3 or 5 hours
Exposure 8: 20 Hz
Exposure duration: 1, 3 or 5 hours

Exposure 1

Main characteristics
Frequency 15 Hz
Type
Waveform
Exposure duration 1, 3 or 5 hours
Additional info applied in pulses
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.5 mT - measured - -

Exposure 2

Main characteristics
Frequency 20 Hz
Type
Waveform
Exposure duration 1, 3 or 5 hours
Additional info applied in pulses
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.5 mT - measured - -

Exposure 3

Main characteristics
Frequency 15 Hz
Type
Waveform
Exposure duration 1, 3 or 5 hours
Additional info applied in pulses
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 3 mT - measured - -

Exposure 4

Main characteristics
Frequency 20 Hz
Type
Waveform
Exposure duration 1, 3 or 5 hours
Additional info applied in pulses
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 3 mT - measured - -

Exposure 5

Main characteristics
Frequency 15 Hz
Type
Waveform
Exposure duration 1, 3 or 5 hours
Additional info applied in pulses
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 4.5 mT - measured - -

Exposure 6

Main characteristics
Frequency 20 Hz
Type
Waveform
Exposure duration 1, 3 or 5 hours
Additional info applied in pulses
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 4.5 mT - measured - -

Exposure 7

Main characteristics
Frequency 15 Hz
Type
Waveform
Exposure duration 1, 3 or 5 hours
Additional info applied in pulses
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 6 mT - measured - -

Exposure 8

Main characteristics
Frequency 20 Hz
Type
Waveform
Exposure duration 1, 3 or 5 hours
Additional info applied in pulses
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 6 mT - measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Hypoxia/reoxygenation treatment alone (group 2) significantly increased apoptosis und decreased cell viability compared to control cell cultures. However, the magnetic field exposure, especially at 4.5 mT/15 Hz and 3 hours before or after the hypoxia/reoxygenation treatment significantly decreased the apoptosis and enhanced cell viability compared to cell cultures with hypoxia/reoxygenation treatment alone. The levels of superoxide und peroxynitrite and the enzyme activity of NADPH oxidase were significantly decreased in the magnetic field exposed groups compared to group 2 (independent whether exposure was before or after hypoxia/reoxygenation treatment) while the level of nitric oxide and the protein expression of the phosphorylated endothelial nitric oxide synthase were significantly increased.
The authors conclude, that low frequency magnetic fields could protect cardiac rat myocytes against ischemia re-perfusion injury via a modulation of the reactive oxygen species formation. Hence, low frequency magnetic fields might present a promising tool for the prevention of cardiac ischemia re-perfusion injuries.

Study character:

Study funded by

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