© Borgis - New Medicine 3/2009, s. 58-60
*Ewa Ogłodek1, Danuta Mo?1, 2
The Effect of Extremely Low Frequency Magnetic Fields on Osteogenesis
1Department of Clinical Psychiatry of the Nicolaus Copernicus University in Toruń, Collegium Medicum in Bydgoszcz, Poland
Head of Clinic: prof. dr hab med. Aleksander Araszkiewicz
2Individual medical practice
Extremely low frequency magnetic fields (ELF-MF) which are applied in the treatment of humans are distinguished from various sorts of magnetic fields. They are magnetic fields of frequency not higher than 60 Hz, induction value ranging from 1 pT to 15 mT, with volume of 130 V/m, and both rectangular and triangular waveform of the magnetic field. The essential problem raised is the effect of the magnetic field on particular metabolic processes of living organisms. The long-term exposure of an organism to extremely low frequency magnetic fields intensifies the process of membrane transmission, resulting in morphological changes in the bone. The use of magnetic fields is gaining acceptance for the treatment of ununited fractures. As a reaction to the stress stimulus in the form of extremely low frequency magnetic fields activity, an increase of biosynthesis of cellular proteins and of transcription in a cell are observed and also changes in expression and differentiation of genes occur.
Extremely low frequency magnetic fields stimulate bone formation by promoting osteoblastic differentiation and activation. In the matrix development and mineralization stages, the calcium content in the matrix and two markers of osteoblastic phenotype (alkaline phosphatase and osteocalcin) also showed a significant increase. The objective of this research was to evaluate the influence of extremely low frequency magnetic fields on osteogenesis.
Extremely low frequency magnetic fields have now been in use in orthopaedics and traumatology for over twenty years [1, 2]. Clinical trials have shown that magnetic stimulation enhances calcification of bones . The technique is employed to promote osteogenesis and hence to favour bone repair processes. It has recently been shown that extremely low frequency magnetic field (ELF-MF) may be the treatment of choice in avascular necrosis of the femoral head. The effect of ELF-MF on the proliferative activity of osteoblasts in vitro and on the speed of the osteogenic repair process in vivo is more evident and ample when cultures of cells are taken from elderly donors or when the examined subject is in advanced age [4, 5].
The objective of this study was to evaluate the influence of extremely low frequency magnetic fields on the growth of osteoblast cells.
Mechanism of the effect of extremely low frequency magnetic field on bone cells
The proliferation and differentiation, which are responsible for growth, remodelling, and repair of bones are modulated by several extracellular factors, such as cytokines and hormones . Bone formation is also affected by pulsed magnetic fields. Extremely low frequency magnetic fields are extensively applied in the clinical treatment of non-union bone fractures, bone grafts, fresh fractures and osteoporosis. As for the effects of pulsed electromagnetic fields on bone, much evidence suggests that they enhance the activities of osteoblasts, proliferation and differentiation, extracellular matrices, alkaline phosphatase and net flux and the uptake of calcium [7, 8].
While several different mechanisms may contribute to the overall healing effectiveness of ELF-MF (increased proliferation and differentiation of pre-osteogenic cells, increased blood flow, increased ion concentration in bone), altered hormone receptor activity seems to play a pivotal role [9, 10]. Osteoblasts exposed for as little as 10 min to pulsed ELF-MF with peak fields in the range of 1 mT show persistent desensitization of the PTH receptor resulting in a rate of collagen synthesis elevated by the osteoblasts, and a rate of bone resorption decreased by osteoclasts [11, 12]. Exposure to the extremely low frequency magnetic field caused increased calcium, leading to phosphorylation of membrane proteins, PKC-induced desensitization of the PTH receptor, and other signal transduction to the cellular membrane. The ELF-MF caused changes in the charge and/or affinity properties of membrane proteins [13, 14].
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Adres do korespondencji:
Department of Psychiatry, Nicolaus Copernicus University, Toruń,
Medical University of Bydgoszcz, Kurpińskiego Str. 19, Bydgoszcz, 85-096
New Medicine 3/2009
Strona internetowa czasopisma New Medicine