Differentiation of osteoprogenitor cells is induced by high-frequency pulsed electromagnetic fields

J Craniofac Surg. 2012 Mar;23(2):586-93. doi: 10.1097/SCS.0b013e31824cd6de.

Abstract

Craniofacial defect repair is often limited by a finite supply of available autologous tissue (ie, bone) and less than ideal alternatives. Therefore, other methods to produce bony healing must be explored. Several studies have demonstrated that low-frequency pulsed electromagnetic field (PEMF) stimulation (ie, 5-30 Hz) of osteoblasts enhances bone formation. The current study was designed to investigate whether a Food and Drug Administration-approved, high-frequency PEMF-emitting device is capable of inducing osteogenic differentiation of osteoprogenitor cells. Osteoprogenitor cells (commercially available C3H10T1/2 and mouse calvarial) in complete Dulbecco modified Eagle medium were continuously exposed to PEMF stimulation delivered by the ActiPatch at a frequency of 27.1 MHz. Markers of cellular proliferation and early, intermediate, and terminal osteogenic differentiation were measured and compared with unstimulated controls. All experiments were performed in triplicate. High-frequency PEMF stimulation increases alkaline phosphatase activity in both cell lines. In addition, high-frequency PEMF stimulation augments osteopontin and osteocalcin expression as well as mineral nodule formation in C3H10T1/2 cells, indicating late and terminal osteogenic differentiation, respectively. Cellular proliferation, however, was unaffected by high-frequency PEMF stimulation. Mechanistically, high-frequency PEMF-stimulated osteogenic differentiation is associated with elevated mRNA expression levels of osteogenic bone morphogenetic proteins in C3H10T1/2 cells. Our findings suggest that high-frequency PEMF stimulation of osteoprogenitor cells may be explored as an effective tissue engineering strategy to treat critical-size osseous defects of the craniofacial and axial skeleton.

Abbreviations: ALP, alkaline phosphatase; BMP, bone morphogenetic protein; ERK-1, extracellular signal-regulated kinase 1; iCALs, immortalized calvarial cells; IHC, immunohistochemical; MAP, mitogen-activated protein; MSC, mesenchymal stem cell; OCN, osteocalcin; OPN, osteopontin; p38α, p38-reactivating kinase; PBS, phosphate-buffered saline; PEMF, pulsed electromagnetic field.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaline Phosphatase / metabolism
  • Animals
  • Bone Morphogenetic Proteins / metabolism
  • Cell Differentiation / radiation effects*
  • Cells, Cultured
  • Electromagnetic Fields*
  • Immunoenzyme Techniques
  • Mice
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Mitogen-Activated Protein Kinases / metabolism
  • Osteoblasts / metabolism
  • Osteoblasts / radiation effects*
  • Osteocalcin / metabolism
  • Osteopontin / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Skull / cytology*
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • Bone Morphogenetic Proteins
  • Osteocalcin
  • Osteopontin
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinases
  • mitogen-activated protein kinase 11, mouse
  • p38 Mitogen-Activated Protein Kinases
  • Alkaline Phosphatase