Real-time measurement of cytosolic free calcium concentration in Jurkat cells during ELF magnetic field exposure and evaluation of the role of cell cycle

✍ Scribed by Cheryl R. McCreary; S. Jeffrey Dixon; Laurence J. Fraher; Jeffrey J.L. Carson; Frank S. Prato

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 167 KB
• Volume: 27
• Category: Article
• ISSN: 0197-8462
• DOI: 10.1002/bem.20248

✦ Synopsis

Abstract

Extremely low frequency magnetic fields (ELF MF) have been reported to alter a number of cell signaling pathways, including those involved in proliferation, differentiation and apoptosis where cytosolic free calcium ([Ca^2+^]~c~) plays an important role. To better understand the biological conditions under which ELF MF exposure might alter [Ca^2+^]~c~, we measured [Ca^2+^]~c~ by ratiometric fluorescence spectrophotometry during exposure to ELF MF in Jurkat E6.1 cells synchronized to different phases of the cell cycle. Suspensions of cells were exposed either to a near zero MF (Null) or a 60 Hz, 100 µT sinusoidal MF superimposed upon a collinear 78.1 µT static MF (AC + DC). An initial series of experiments indicated that the maximum increase in [Ca^2+^]~c~ above baseline after stimulation with anti‐CD3 was significantly higher in samples exposed to AC + DC (n = 30) compared to Null (n = 30) with the largest difference in G2‐M enriched samples. However, in a second study with G2‐M enriched cells, samples treated with AC + DC (n = 17) were not statistically different from Null‐treated samples (n = 27). Detailed analysis revealed that the dynamics in [Ca^2+^]~c~ before and after stimulation with anti‐CD3 were dissimilar between Null samples from each study. From the results, we concluded (i) that the ELF MF increased [Ca^2+^]~c~ during an antibody‐induced signaling event, (ii) that the ELF MF effect did not depend to a large degree on cell cycle, and (iii) that a field‐related change in [Ca^2+^]~c~ signaling appeared to correlate with features in the [Ca^2+^]~c~ dynamics. Future work could evaluate [Ca^2+^]~c~ dynamics in relation to the phase of the cell cycle and inter‐study variation, which may reveal factors important for the observation of real‐time effects of ELF MF on [Ca^2+^]~c~. Bioelectromagnetics 27:354–364, 2006. © 2006 Wiley‐Liss, Inc.