Study type: Medical/biological study (experimental study)

Sinusoidal electromagnetic fields promote bone formation and inhibit bone resorption in rat femoral tissues in vitro. med./bio.

Published in: Electromagn Biol Med 2016; 35 (1): 75-83

Aim of study (acc. to author)

The effects of exposure of cultured rat femur tissue to a 50 Hz magnetic field on bone formation and resorption and gene expression of associated markers should be investigated.

Background/further details

To examine the major types of bone tissues in a long bone, femoral diaphysis (mainly cortical bone) and metaphysis (containing a large amount of trabecular bone) tissues were extracted from rats, cultured for 48 hours and exposed to the magnetic field.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: 1.5 hours/day for up to 12 days

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration 1.5 hours/day for up to 12 days
Exposure setup
Exposure source
Chamber 60-mm culture dishes in a CO2 incubator (5% CO2, 37°C and 100% humidity)
Setup 6 culture dishes were exposed at a time and placed within the solenoid, which was composed of a core cylinder of acrylic tube (inner diameter: 18 cm; height: 21 cm) and three series-connected coils, which respectively had 24 x 8, 24 x 7 and 24 x 8 turns, with the dimension of the wire being 5 mm x 2 mm; the magnetic field was homogeneous with <5% both horizontally and vertically error
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.8 mT - measured - -

Reference articles

  • Zhou J et al. (2014): Different electromagnetic field waveforms have different effects on proliferation, differentiation and mineralization of osteoblasts in vitro.
  • Zhou J et al. (2011): Effects of 50 Hz sinusoidal electromagnetic fields of different intensities on proliferation, differentiation and mineralization potentials of rat osteoblasts.

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

In exposed femoral diaphyseal and metaphyseal tissues, a significant increase in alkaline phosphatase enzyme activity and a significant decrease in tartrate-resistant acid phosphatase enzyme activity compared to the control group was found. Moreover, significantly increased gene expressions of bone formation-related genes osterix, insulin-like growth factor and alkaline phosphatase were observed in both bone tissues after exposure to the magnetic field compared to the control group.
A significantly decreased glucose content and significantly increased lactate content were observed in both bone tissue culture media after exposure to the magnetic field compared to the control group. The gene expressions of bone resorption-related genes tartrate-resistant acid phosphatase, macrophage colony stimulating factor and cathepsin K were significantly decreased in both exposed tissues compared to the control groups.
The authors conclude that exposure of cultured rat femur tissue to a 50 Hz magnetic field might promote bone formation, increase the metabolism and reduce bone resorption.

Study character:

Study funded by

Related articles