| Pulsed electromagnetic fields (PEMFs) have been used extensively in bone fracture repair and wound healing. The rationale for using pulsed magnetic fields was based on the assumption that the induced electric field is the source of the stimulus. There is accumulating experimental evidence that weak magnetic fields of intensity near the geomagnetic field can interact with biological systems. However, physical arguments deny the possibility of observing biological effects at this level of magnetic strength. The main point of concern is how a low level magnetic signal can be transformed into a biological response. In fact, thermal noise effects hinder most models of biophysical interactions.;The first part of the present study examines the response of human umbilical vein endothelial cells to weak static magnetic fields. Proliferation, viability, and the expression of functional parameters such as eNOS, NO, and also gene expression of VEGF under the influence of different doses of weak magnetic fields were investigated. Applications of weak magnetic fields in tissue engineering are also discussed. Static magnetic fields may open new venues of research in the field of vascular therapies by promoting endothelial cell growth and by enhancing the healing response of the endothelium.;Several experimental tests are conducted in the second part of the study in order to determine the mechanism of interaction between the electromagnetic fields and the biological system. The tests are designed to differentiate between two types of mechanisms: (1) the slow type, which is capable of sensing the frequency of the fields, and the relative orientation, and (2) the fast type, which senses the absolute magnitude of the magnetic field. The results obtained indicate that the transductive mechanism is only sensitive to the magnitude of the applied external magnetic field. |
