Evaluation of the influence of in vivo exposure to extremely low-frequency magnetic fields on the plasma levels of pro-inflammatory cytokines in rats.

PURPOSE

Epidemiological data suggest that there is a link between exposure to extremely low-frequency magnetic fields (ELF-MFs), immune response, and the occurrence of neurodegenerative diseases. The exact nature of this phenomenon remains speculative and requires detailed laboratory investigation. In the present study, we evaluate changes in plasma concentration of pro-inflammatory and regulatory cytokines as well as alternations of the hematological parameters in rats exposed to an ELF-MF.

MATERIALS AND METHODS

Male Wistar rats were repeatedly exposed for either 1 h/day for 7 days, or continuously for 24 h, to a sinusoidal ELF-MF (50 Hz, 7 mT). Control groups were sham exposed for either 1 h/day for 7 days, or continuously for 24 h, respectively. The levels of cytokines: interleukin (IL)-1β, IL-2, IL-6, and IL-10 in plasma obtained from blood samples were determined using enzyme-linked immunosorbent assay (ELISA). The changes in blood parameters were determined using an automatic hematology analyzer in whole blood samples immediately after collection.

RESULTS

We found that a single continuous (lasting 24 h) exposure provoked a significant increase of the plasma IL-1β, IL-6, and IL-2 levels, and caused an elevation in blood parameters, such as white blood cells, lymphocytes, hemoglobin, and hematocrit levels. In contrast, however, repetitive exposure of rats to an ELF-MF for 1 h/day for 7 days did not lead to any changes in plasma levels of cytokines and hematological counts.

CONCLUSIONS

Based on these data we conclude that exposure duration (dose-response) plays a significant role in the immune response, specifically at the cellular level. While single 24 h-lasting exposure provoked changes that indicate an immune alarm stimulation, under the conditions which are typical for therapeutic use of ELF-MFs (repeated short daily exposure) the immune potentially harmful response has not been observed.