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.
Exposure duration: continuous for 72 h
|magnetic flux density||1.8 mT||-||measured||-||-|
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.