Non-thermal Biological Effects Of Electromagnetic Fields And Its Mechanism

The 50Hz pulsed electric field (PEF) can cause a series of bio-effects: the decrease of binding ratio of insulin to its receptor, the suppressed level of tyrosine phosphorylation and the changes of gene expression. The conformation changes of insulin was detected by Raman spectrum after it was exposed to PEF. And results were consistent with the above bio-effects. From the view of cell signal transduction , insulin, as an intercellular signal molecule, transferred the effects of electric field into the cell through binding to its receptor. It is the way the PEF triggered bio-effects.50Hz sinusoidal magnetic field suppressed cell proliferation and caused EGFR (epidermal growth factor receptor )clustering on the membrane of CHL cell. Meanwhile the clustering of purified EGFR is observed after exposed to the magnetic field by AFM. And EGFR is a key point on the signal pathway.The conclusion can be reached that a weak EMF may lead to bio-effects through affecting signal pathways. And it reveals an important mechanism of the non-thermal EMF bio-effects .With the assay of membrane fluidity, we can presume that membrane, receptors and intercellular signal molecules are action sites of EMF.The current EMF exposure standard of 50Hz sinusoidal magnetic field in China is 0.1 mT and exposure time is less than 8 hours. The results of cell proliferation show it is safe . But theoretical calculation showed the assumption that magnetic fields act through its induced electric fields is not reasonable.