Linearly and circularly polarized, 50 Hz magnetic fields did not alter intracellular calcium in rat immune cells

This study was conducted to determine if exposure to 50 Hz magnetic field (MF) affects intracellular calcium ([Ca2+](i)). We employed flow cytometry for real-time detection of possible changes in [Ca2+](i) in a large number of cells. A solenoid coil for vertical MF exposure and a multiple-loop square-coil for horizontal MF were utilized. In the laboratory, background 50 Hz MF was less than 0.08 mu T when all necessary equipment was powered. Rat thymocytes were exposed to 0.1 mT horizontal or vertical field, or to 0.14 mT circularly polarized field for 30 min; the effects of consecutive exposures to vertical and horizontal MFs, or vice versa, for 20 min each also were examined. In addition, intact thymocytes or lectin-activated thymocytes, splenocytes and peripheral blood lymphocytes were exposed to the 5 mT vertical field for 30 min. In all these experiments, no alteration in [Ca2+](i) was evident. As a positive control, a calcium ionophore always was added to the medium following MF exposure to verify that the cells were capable of increasing [Ca2+](i) and the system would record the response. The data indicate that MF exposure had no effect on [Ca2+](i) under any of the conditions examined.