Serum plays a critical role in modulating [Ca2+]c of primary culture bone cells exposed to weak ion-resonance magnetic fields
✍ Scribed by Kirk A. Reinbold; Solomon R. Pollack
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 156 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0197-8462
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✦ Synopsis
Primary-culture bone cells were exposed to ion-resonance (IR) magnetic fields tuned to Ca 2/ . Cytosolic calcium concentration, [Ca 2/ ] c , was measured by using fura-2 during field exposure. The fields investigated were 20 mT static / 40 mT p-p at either 15.3 or 76.6 Hz, and 0.13 mT static / either 0.5 or 1.0 mT p-p at 100 Hz. Other parameters included field orientation, culture age (2 or 5 days after plating), and the presence of serum (0 or 2%) during exposure. Total experiment time was 29.5 min:
The field was applied after 2 min, and bradykinin was added as an agonist control after 22 min. The data were quantified on a single-cell basis during the 2 -22 min exposure period in terms of the magnitude of the largest occurring [Ca 2/ ] c spike normalized to local baseline. Field-exposed and control groups were characterized in terms of the percent of cells exhibiting spike magnitudes above thresholds of 100 or 66% over baseline and were compared by using Fisher's exact test. Without serum, there was little evidence that IR magnetic fields altered [Ca 2/ ] c . However, in the presence of 2% serum, 3 of the 16 experiments exhibited significant effects at the 100% threshold. Reducing this threshold to 66% resulted in five experiments exhibiting significant effects. Most strikingly, in all of these cases, the field acted to enhance [Ca 2/ ] c activity as opposed to suppressing [Ca 2/ ] c activity. These findings suggest a role for serum or for constituents within serum in mediating the effects of IR magnetic fields on cells and may provide a resolution pathway to the dilemma imposed by theoretical arguments regarding the possibility of such phenomena. Possible roles of serum and future studies are discussed.