Study type: Medical/biological study (experimental study)

Pulsed electromagnetic fields promote osteoblast mineralization and maturation needing the existence of primary cilia. med./bio.

Published in: Mol Cell Endocrinol 2015; 404: 132-140

Aim of study (acc. to author)

The effects of exposure of rat calvarial osteoblasts to a pulsed 50 Hz magnetic field on cell proliferation and differentiation as well as and the role of primary cilia in this context should be investigated.

Background/further details

Cells were divided into the following groups: exposure to a magnetic field with 1) 0.6 mT, 2) 1.2 mT, 3) 1.8 mT, 4) 2.4 mT, 5) 3.0 mT, 6) 3.6 mT and 7) sham exposure. Additionally, cells with a block in primary cilium formation were created via transfection by siRNA and a resulting suppressed expression of the intraflagellar transport (IFT) protein 88. These cells were exposed to a 0,6 mT magnetic field (group 8).
Each experiment was conducted with n=3 samples per group and was repeated 3 times.

Endpoint

Exposure

Exposure Parameters
Exposure 1:
Exposure duration: continuous for 90 minutes/day for up to 12 days
Exposure 2:
Modulation type: pulsed
Exposure duration: continuous for 90 minutes/day for up to 12 days
Exposure 3:
Modulation type: pulsed
Exposure duration: continuous for 90 minutes/day for up to 12 days
Exposure 4:
Modulation type: pulsed
Exposure duration: continuous for 90 minutes/day for up to 12 days
Exposure 5:
Modulation type: pulsed
Exposure duration: continuous for 90 minutes/day for up to 12 days
Exposure 6:
Modulation type: pulsed
Exposure duration: continuous for 90 minutes/day for up to 12 days

Exposure 1

Main characteristics
Frequency
Type
Waveform
Exposure duration continuous for 90 minutes/day for up to 12 days
Additional info 50 Hz pulsed unipolar magnetic field with 50% duty ratio
Exposure setup
Exposure source
Chamber 60-mm culture dishes
Setup solenoid (27 cm long, three series-connected coils and lead tube core cylinder with inner diameter of 100 mm) was placed in a CO2 incubator (5% CO2, 37 °C and 100% humidity); fields had an error of <0.1% horizontally (from 60 to -60 mm) and <0.05% vertically (from 45 to -45 mm)
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.6 mT - measured - -

Exposure 2

Main characteristics
Frequency
Type
Waveform
Exposure duration continuous for 90 minutes/day for up to 12 days
Additional info 50 Hz pulsed unipolar magnetic field with 50% duty ratio
Modulation
Modulation type pulsed
Duty cycle 50 %
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.2 mT - measured - -

Exposure 3

Main characteristics
Frequency
Type
Waveform
Exposure duration continuous for 90 minutes/day for up to 12 days
Additional info 50 Hz pulsed unipolar magnetic field with 50% duty ratio
Modulation
Modulation type pulsed
Duty cycle 50 %
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.8 mT - measured - -

Exposure 4

Main characteristics
Frequency
Type
Waveform
Exposure duration continuous for 90 minutes/day for up to 12 days
Additional info 50 Hz pulsed unipolar magnetic field with 50% duty ratio
Modulation
Modulation type pulsed
Duty cycle 50 %
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2.4 mT - measured - -

Exposure 5

Main characteristics
Frequency
Type
Waveform
Exposure duration continuous for 90 minutes/day for up to 12 days
Additional info 50 Hz pulsed unipolar magnetic field with 50% duty ratio
Modulation
Modulation type pulsed
Duty cycle 50 %
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 3 mT - measured - -

Exposure 6

Main characteristics
Frequency
Type
Waveform
Exposure duration continuous for 90 minutes/day for up to 12 days
Additional info 50 Hz pulsed unipolar magnetic field with 50% duty ratio
Modulation
Modulation type pulsed
Duty cycle 50 %
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 3.6 mT - measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

Cell proliferation was significantly increased in groups 1-6 compared to the sham exposure group with the most distinct increase in group 1 (0.6 mT).
The parameters for differentiation and mineralization also showed the highest and most distinctly significantly increased values in group 1 in comparison to the sham exposure group without exceptions.
Differentiation and mineralization were significantly reduced in group 8 compared to group 1 and no significant differences could be found compared to the sham exposure group.
The authors conclude that exposure of rat calvarial osteoblasts to a pulsed 50 Hz magnetic field with 0.6 mT might stimulate cell proliferation, differentiation and mineralization and that the primary cilium plays an essential role in mediating this effects.

Study character:

Study funded by

Related articles