Exposure of mouse preosteoblasts to pulsed electromagnetic fields reduces the amount of mature, type I collagen in the extracellular matrix

Abstract

We tested the hypothesis that exposure of a mouse preosteoblast cell line to pulsed electromagnetic fields (PEMF) would affect components of the extracellular matrix. We report that exposure of MC3T3-E1 cells to a single PEMF waveform significantly reduced the amount of mature, a1(I) collagen in the extracellular matrix (ECM) and the conditioned medium, without affecting the amount of total ECM protein. This decrease was not due to changes in the steady-state level of Col1A1 mRNA or to degradation of mature collagen. We then tested the effect of three distinct PEMF waveforms, two orthogonal coil orientations, and two waveform amplitude levels on the amount of a1(I) collagen in the conditioned medium. A sequence of factorial ANOVAs and stepwise regression modeling revealed that the period (duration) of the individual pulses accounted for a significant proportion of the variance associated with the amount of a1(I) collagen in the conditioned medium. The total variance accounted for, however, was small (R 2 ¼ 0.155, p < 0.001 and R 2 ¼ 0.172, p < 0.001, in the horizontal and vertical orientations, respectively). The positive and negative regression coefficients for the coil orientations revealed that the influence of pulse period was significantly different for the orthogonal coil orientations (p < 0.001). The findings imply that the dominant influence of PEMF on the amount of mature, a1(I) collagen in the ECM is related to variables other than those expressed in the time-amplitude domain. The results provide objective direction toward identifying waveform characteristics that contribute to the observed between-waveform differences with regard to collagen. Advances in this area may lead toward improving waveforms and waveform delivery protocols. ß

Effect of pulsed electromagnetic field on the proliferation and differentiation potential of human bone marrow mesenchymal stem cells

“…There are quite a few studies analyzing the effects of PEMF stimulation on cell lines and on non-human osteoblasts in vitro [Lohmann et al, 2000[Lohmann et al, , 2003Diniz et al, 2002;Sakai et al, 2006;Selvamurugan et al, 2007]. Diniz et al [2002] showed that PEMF treatment of osteoblasts in the early stages accelerated cellular proliferation, enhanced cellular differentiation, and increased bone tissue-like formation.…”

Pulsed electromagnetic fields enhance BMP‐2 dependent osteoblastic differentiation of human mesenchymal stem cells

“…However, because coils were active in only one incubator, any resulting vibrations might not have been equivalent in the control and experimental cultures. At harvest [days 0 (confluence), 6,12,16,20,24], cultures were examined for expression of an osteoblastic phenotype based on ALP specific activity of cell layer lysates and osteocalcin levels in the conditioned media.…”

“…20,21 While biophysical forces appear to regulate osteoblasts via mechanisms involving growth factors and cytokine release, differences in cell response are signal specific. However, it has been difficult to determine if differences in responses to biophysical factors are due to: the type of signal (PEMF, static magnetic fields, capacitively coupled electric fields, combined magnetic fields, or direct current) 22,23 ; the form or duration of a specific signal 24 ; or to differences in the cell culture model used. Although PEMF directly affects osteoblasts, it has not been reported to induce MSCs to exhibit an osteoblast phenotype in vitro.…”

Effects of low frequency electromagnetic fields on the chondrogenic differentiation of human mesenchymal stem cells

“…Electric and electromagnetic potentials were discovered not only to affect osteogenesis [Massari et al, 2006;Sakai et al, 2006] but also to act chondroprotectively in vivo and in vitro [Trock et al, 1993;Ciombor et al, 2003;De Mattei et al, 2003;Fini et al, 2008]. Electromagnetic fields (EMF) showed a significant pain reduction and an improvement in range of motion for patients with osteoarthritis (OA) [Trock et al, 1993].…”