Study type: Medical/biological study (experimental study)

Comparison of Effects of Pulsed Electromagnetic Field Stimulation on Platelet-Rich Plasma and Bone Marrow Stromal Stem Cell Using Rat Zygomatic Bone Defect Model. med./bio.

Published in: Ann Plast Surg 2015; 75 (5): 565-571

Aim of study (acc. to author)

The effects of exposure of rats with an experimental zygomatic bone fracture to a pulsed 50 Hz magnetic field in combination with other therapeutical treatments on bone healing should be investigated.

Background/further details

Isogeneic (inbred) rats were divided into 9 groups (n=15 rats each): 1) exposure to the sinusoidal magnetic field, 2) exposure to the pulsed magnetic field, 3) treatment with platelet-rich plasma, 4) treatment with bone marrow stromal stem cells, 5) co-exposure to the sinusoidal and pulsed magnetic field, 6) exposure to the pulsed magnetic field and treatment with platelet-rich plasma, 7) exposure to the pulsed magnetic field and treatment with bone marrow stromal stem cells, 8) sham group (no exposure or treatment, only bone fracture) and 9) control group (no exposure, no treatment, no bone fracture).
Except for the control groups, rats in all groups underwent a surgery to induce an experimental non-union fracture of the zygomatic bone. Treatments with platelet-rich plasma or bone marrow stromal stem cells took place directly after creation of the fracture during the same surgery. Exposure to the magnetic fields started on the 7. day after the surgery/treatments.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 8 hours/day for 1 month
Exposure 2: 50 Hz
Modulation type: pulsed
Exposure duration: continuous for 8 hours/day for 1 month

General information

remark EMF-Portal: as the same exposure device was used for the purpose of obtaining a magnetic field with pulse via intermittent flow of power supply and to obtain a sinusoidal field via constant power flow, it is not evident how a co-exposure to both fields (group 5) was realized

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 8 hours/day for 1 month
Exposure setup
Exposure source
Chamber plexiglass and methacrylate cage (43 x 42 x 15 cm3)
Setup Helmholtz coils (70 cm diameter) were placed into a Plexiglas Faraday cage (130 x 65 x 80 cm3); the distance between the 2 coils was adjusted to 47 cm (remark EMF-Portal: Helmholtz configuration?); the magnetic field was created with copper wires, which had 125 loops of 1.5 mm diameter; not clear, where the animal cages were placed
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.5 mT - - - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 8 hours/day for 1 month
Modulation
Modulation type pulsed
Pulse width 25 µs
Exposure setup
Exposure source
Setup intermittent flow of power supply was used for the purpose of obtaining magnetic field with pulse
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.5 mT - - - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

After 6 months, the bone density showed significant differences between the groups. The highest mean bone density was found in the control group (group 9). Group 6 (pulsed magnetic field and platelet-rich plasma) showed the second highest value followed by group 7 (pulsed magnetic field and bone marrow stromal stem cells).
Regarding the marker levels, significant differences between the groups were found as well. The highest values of hydroxyproline in urine and in bone tissue, alkaline phosphatase and osteocalcin in the blood were found in group 6.
Histopathological comparison of the groups did not point out any differences regarding inflammation. The highest increase in terms of blood vessel formation was observed in group 6, whereas the lowest increase was seen in group 7. The values closest to the control groups in terms of collagen fibrils and osteocyte ratio were found in groups 6 and 7.
The authors conclude that exposure of rats with an experimental zygomatic bone fracture to a pulsed 50 Hz magnetic field in combination with a treatment with platelet-rich plasma might be beneficial for bone healing and useful for clinical applications.

Study character:

Study funded by

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