Serum plays a critical role in modulating [Ca{sup 2+}]{sub c} of primary culture bone cells exposed to weak ion-resonance magnetic fields
- Univ. of Pennsylvania Medical Center, Philadelphia, PA (United States). Dept. of Rehabilitation Medicine
- Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Bioengineering
Primary-culture bone cells were exposed to ion-resonance (IR) magnetic fields tuned to Ca{sup 2+}. Cytosolic calcium concentration, [Ca{sup 2+}]{sub c}, was measured by using fura-2 during field exposure. The fields investigated were 20 {micro}T static + 40 {micro}T 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, and the presence of serum 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{sup 2+}]{sub 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{sup 2+}]{sub 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{sup 2+}]{sub c} activity as opposed to suppressing [Ca{sup 2+}]{sub 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.
- Sponsoring Organization:
- National Science Foundation, Washington, DC (United States)
- OSTI ID:
- 462565
- Journal Information:
- Bioelectromagnetics, Vol. 18, Issue 3; Other Information: PBD: 1997
- Country of Publication:
- United States
- Language:
- English
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