Medical/biological study (experimental study)

Pulsed electromagnetic field stimulates cellular proliferation in human intervertebral disc cells med./bio.

By: Lee HM, Kwon UH, Kim H, Kim HJ, Kim B, Park JO, Moon ES, Moon SH

Published in: Yonsei Med J 2010; 51 (6): 954-959

Aim of study (acc. to author)

To study the mechanism of electromagnetic field effects on cell proliferation of human intervertebral disc cells.

Background/further details

Human intervertebral disc tissue specimens were obtained from eight patients.
Cell cultures were divided into a control group and an exposure group with or without N-monomethyl-L-arginine (inhibitor of nitric oxide) or acetylsalicylic acid (inhibitor of prostaglandin E2) to elucidate the mechanism of action of the electromagnetic field on cell proliferation.

Endpoint

molecular biosynthesis: proteoglycan synthesis, gene expression of aggrecan and collagen type I and II
cell viability/cell division/proliferation: cell proliferation

Exposure

Exposure	Parameters
Exposure 1: 30–60 Hz Exposure duration: continuous for 72 h	magnetic flux density: 1.8 mT

General information

Cells were treated with N(G)-Monomethyl-L-arginine or Acetylsalicylic Acid before exposure to EMF

Exposure 1

Main characteristics

Frequency	30–60 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	continuous for 72 h
Additional info	The article is contradictory in regard to the frequency used for exposure - maybe 30 Hz (as stated in methods), maybe 60 Hz (as stated in the abstract)

Exposure setup

Exposure source	solenoid
Setup	30 cm high solenoid with a diameter of 12 cm, consisting of a polyethylene cylinder tube wound with copper; cells placed in three-dimensional alginate beads in the center of the solenoid

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	1.8 mT	-	measured	-	-

Reference articles

McLeod KJ et al. (2000): Suppression of a differentiation response in MC-3T3-E1 osteoblast-like cells by sustained, low-level, 30 Hz magnetic-field exposure

Exposed system:

intact cell/cell culture
human intervertebral disc cells

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: proteoglycan synthesis (³⁵S-sulfate incorporation and scintillation counting), gene expression of aggrecan and collagen type I and II (RT-PCR)
cell viability/cell division/proliferation: cytotoxicity: cell proliferation, cell viability (MTT assay and evaluated via DNA synthesis (³H-thymidine incorporation and scintillation counting))

Investigated system:

DNA/RNA
intact cell/cell culture

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The MTT assay revealed no cytotoxicity in intervertebral disc cells of the exposed group implying cell proliferation without cytotoxicity. Cell proliferation as measured by ³H-thymidine incorporation significantly increased (53%) in the exposed cell culture compared to control cultures.
There was no difference in newly synthesized proteoglycan between the exposed cells and the control cells. Electromagnetic field exposed cell cultures showed no significant change in the expression of aggrecan and type I, and type II collagen compared to the control cells.
Treatment with N-monomethyl-L-arginine or acetylsalicylic acid of exposed cells demonstrated decreased DNA synthesis compared to control cultures without inhibitor treatment.
The authors conclude that electromagnetic field exposure stimulated DNA synthesis in human intervertebral disc cells while no significant effect on proteoglycan synthesis and chondrogenic phenotype expressions was found. DNA synthesis was partially mediated by nitric oxide and prostaglandin E2. Electromagnetic fields can be utilized to stimulate cell proliferation of intervertebral disc cells, which may provide efficient cell amplification in cell therapy to degenerative disc disease.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

BrainKorea21 (BK 21) Project, Korea Research Foundation, Korea
Yonsei University College of Medicine (CMB-Yuhan research grant), Korea

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