3T3 cell motility and morphology before, during, and after exposure to extremely‐low‐frequency magnetic fields

Abstract

Automated image cytometry techniques were used to measure motility and morphology in 3T3 fibroblasts exposed to extremely-low-frequency (ELF) magnetic fields. Cell motility and morphology were measured as a function of time before, during, and after 3-4 hour exposures to vertically oriented, 100 microTRMS sinusoidal magnetic fields at various frequencies in the 10-63 Hz range. Sham exposures were also carried out. No static DC fields were applied, but the geomagnetic field was almost vertical and, therefore, had a large component (28.3 microT) parallel to the applied AC field. The morphology and motile behavior of the cells were characterized by mathematically defined descriptors, which were calculated and averaged for the exposure period as well as for control periods that preceded and followed the exposure period. Each experiment involved the tracking of 100 cells that were subjected to one of the test frequencies (unless a sham exposure was being conducted). Statistical analysis of the results showed that even small changes of 10-20% could be significant at the P < .05 level. Changes on this order were measured in a significant proportion of the experiments. However, because such results were seen for both the sham-exposed and the ELF-exposed cells, and because the range of values that was obtained for the sham exposures was the same as that obtained for the ELF exposures, we concluded that there was no evidence to show that any of the measured changes were attributable to the applied ELF magnetic field.

50 Hz magnetic fields of varying flux intensity affect cell shape changes in invertebrate immunocytes: The role of potassium ion channels

“…Our results differ from those obtained by Spadinger et al [1995], who reported no evident effect of MFs on cellular changes in 3T3 fibroblasts.…”

Morphologic responses of osteoblast-like cells in monolayer culture to ELF electromagnetic fields

“…Efforts to replicate the studies of Spadinger et al [1995], using a longer exposure duration, resulted in remarkably similar ®ndings. That is, a 0.7 mT magnetic¯ux at 60 Hz, inducing a 0.5 mV/m rms electric ®eld, resulted on average in only slight morphologic changes to the cell population, none of which were signi®cant.…”

“…However, as the morphologic changes are consistently in one direction, it would be expected that analysis of larger cell numbers should show an effect of ®eld exposure at the levels used here even if orientation were not considered. As the tracking assay utilized by Spadinger et al [1995] restricted the analysis to a small number of cells (approximately 100), this orientation effect may help clarify why the morphologic changes they observed never reached statistical signi®cance. This observation may also provide some rationale for why many of the reported cellular responses to ELF ®eld exposures have the tendency to be remarkably small, as compared, for example, to pharmacologic intervention, even when the responses appear quite consistent.…”

“…Because environmental exposures predominantly involve power line frequencies and their harmonics (25±200 Hz), there is strong overlap in the investigations addressing endogenous ®eld effects and environmental hazards. Recently, Spadinger et al [1995] undertook an investigation of low level ®eld effects on cultured cells working in the ELF frequency range (10±63 Hz). This group speci®cally assayed changes in cell motility and morphologic properties of NIH/3T3 ®broblast cells.…”

Effect of static magnetic field on cell migration

“…Available research at the cellular level deals with effects on osteogenesis and proteins, but there has been hardly any quantitative estimation of cell activities observable by a microscope, in particular, cell migration. Studies of cell migration conducted so far have dealt with one or a few cells in a Petri dish [15,16]. For example, Ref.…”