Study type: Medical/biological study (experimental study)

Pulsed electromagnetic fields affect phenotype and connexin 43 protein expression in MLO-Y4 osteocyte-like cells and ROS 17/2.8 osteoblast-like cells. med./bio.

Published in: J Orthop Res 2003; 21 (2): 326-334

Aim of study (acc. to author)

To examine long term effects of pulsed electromagnetic fields (PEMFs) on MLO-Y4 osteocyte-like cells and ROS 17/2.8 osteoblast-like cells.

Background/further details

It was examined if MLO-Y4 cells respond to PEMFs with change in connexin 43 protein expression (essential for gap junction intercellular communication) and altered production of agents involved in bone remodeling; if prostaglandin (essential for the increase in gap junction formation) production modulates the effects of PEMFs; and if the response of osteocytes differs from that of osteoblasts.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 15 Hz
Modulation type: pulsed
Exposure duration: 8 h/d on day 1
Exposure 2: 15 Hz
Modulation type: pulsed
Exposure duration: 8 h/d for 2 days.
Exposure 3: 15 Hz
Modulation type: pulsed
Exposure duration: 8 h/d for 4 days.

Exposure 1

Main characteristics
Frequency 15 Hz
Type
Waveform
Exposure duration 8 h/d on day 1
Modulation
Modulation type pulsed
Rise time 200 µs
Additional info

Burst of 4.5 ms of 20 pulses.

Exposure setup
Exposure source
Chamber Incubator with plastic shelves
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.6 mT maximum unspecified - increased within 200 µs and decreased to 0 within 25 µs.

Exposure 2

Main characteristics
Frequency 15 Hz
Type
Waveform
Exposure duration 8 h/d for 2 days.
Modulation
Modulation type pulsed
Rise time 200 µs
Additional info

Burst of 4.5 ms of 20 pulses.

Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.6 mT maximum unspecified - increased within 200 µs and decreased to 0 within 25 µs.

Exposure 3

Main characteristics
Frequency 15 Hz
Type
Waveform
Exposure duration 8 h/d for 4 days.
Modulation
Modulation type pulsed
Rise time 200 µs
Additional info

Burst of 4.5 ms of 20 pulses.

Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.6 mT maximum unspecified - increased within 200 µs and decreased to 0 within 25 µs.

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

It was shown for the first time that osteocytes respond to pulsed electromagnetic fields (PEMF) stimulation. PEMF affected the release of factors that modulate cell activity via autocrine and paracrine mechansims. PEMFs for 8h/day for one, two or four days increased alkaline phosphatase activity in MLO-Y4 cells but had no effect on cell number or osteocalcin level. Transforming growth factor (TGF)-β1 and prostaglandin E2 were increased, and NO2--level was altered. In ROS 17/2.8 cells, PEMFs for 24, 48 or 72h did not affect cell number, osteocalcin mRNA or osteocalcin protein level. PEMFs reduced connexin 43 protein in both cell cultures. Longer exposure decreased connexin mRNA.

Study character:

Study funded by

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