Time‐varying magnetic fields: Effects of orientation on chondrocyte proliferation

Abstract

The purpose of this study was to determine the effect of orientation of pulsed electromagnetic fields (PEMFs) on cellular proliferation and extracellular matrix synthesis. Bovine articular chondrocytes were cultured in PEMFs (repetitive pulse at 72 Hz) generated using Helmholtz coils oriented either parallel (horizontal) or perpendicular (vertical) to the plane of cell adhesion. Dissipation of signal energy in the form of heat increased the temperature of the PEMF coils by 2 degrees C and the tissue culture medium by 1 degree C. Therefore, control coils, which emitted no PEMFs, were heated to the temperature of PEMF coils by circulating water. Chondrocytes were cultured in 16-mm-well culture plates, and the data for individual wells were pooled as triplicates. Although not observed by microscopic examination of individual wells, positionally dependent electric field effects may be minimized by this approach. PEMFs generated by coils oriented vertically significantly decreased chondrocyte proliferation. The effect was dependent on the concentration of serum in the culture media. At 3% serum concentration, the total cell number attained after 10 days of culture was reduced by 50% in stimulated cultures when compared with controls. At 5% serum concentration, there was no effect. PEMFs applied by coils oriented horizontally did not alter proliferation of articular chondrocytes. PEMFs had no effect on synthesis of extracellular matrix by chondrocytes plated at high density, irrespective of orientation.

Effects of pulsed electromagnetic field (PEMF) stimulation on bone tissue like formation are dependent on the maturation stages of the osteoblasts

“…Despite that, electric stimulation has been used successfully to treat a wide range of bone disorders, including delayed and nonunion fractures [De Haas et al, 1980], fresh fracture healing [Grace et al, 1998], prevention and reverse of osteoporosis [Brighton et al, 1985a,b;McLeod et al, 1992], and congenital pseudarthroses [Kort et al, 1982] among others. However, the clinical success contrasts with negative reports on the effects of electric stimulation on the cellular proliferation, differentiation, and bone formation in vitro [Norton, 1982;Elliott et al, 1988;Iannacone et al, 1988;Norton et al, 1988].…”

Static Electromagnetic Fields Generated by Corrosion Currents Inhibit Human Osteoblast Differentiation

“…21,22 Despite the clinical success, studies on the in vitro effects of electric stimulation on cellular proliferation, differentiation, and bone formation reported conflicting results. [23][24][25][26] Electric and electromagnetic fields increase gene expression for, and synthesis of growth factors and this may contribute to amplify field effects through autocrine and paracrine signaling. Electric and electromagnetic Figure 2.…”

Pulsed electromagnetic fields decrease proinflammatory cytokine secretion (IL-1β and TNF-α) on human fibroblast-like cell culture

“…In the 1980s, the first observations were published regarding the effects of PEMFs on cell cultures [14,24,25]. Since then, studies have been made of the action on osteoblast cultures [11], osteoclasts [8], chondrocytes [18] and, recently, on human bone marrow mesenchymal stem cells (MSC) [33].…”