To investigate the local intracellular distribution and gene expression of "growth associated protein"-43 (GAP-43) in human glioma cells after exposure to a magnetic field (60 Hz, 5 mT), with or without initial X-rays radiation (2 Gy) in vitro.
The investigated "growth associated protein"-43 (GAP-43) is considered to be a marker for development and growth stimulation of cells in brain tissues.
The magnetic flux density, 5 mT, used in this study is the maximum permissible under the guidelines from the "International Non-ionizing Radiation Committee of the International Radiation Protection Association" (IRPA/INIRC) for the short term occupational whole body exposure (2 hours per work day).
The experiments were repeated three times.
|Exposure duration||5, 10, 12 and 24 h|
|Chamber||CO2 incubator with a built-in magnet generator using two Helmholtz coils|
|Additional info||cylindrical exposure space (14 cm height x 20 cm diameter) housing sixteen 10 or four 15 cm culture dishes; inside and outside of the incubator shielded by silicon steel and Permalloy C.|
GAP-43 was present in the cytoplasm, accumulating in the perinuclear area.
Exposure of cells to the extremely low frequency electromagnetic field for 5 hours resulted in a 2.5-fold increase in GAP-43 mRNA levels compared to sham-exposed cells. The transcription level induced by co-exposure was slightly higher than for exposure to X-rays radiation alone, but lower than that for exposure to the magnetic field alone. The kinetic pattern of GAP-43 mRNA levels in X-rays exposed cells were very similar to that in magnetic field exposed cells.
GAP-43 protein expression was about 2-fold higher after 12 hours electromagnetic field exposure compared to sham exposed cells returning to control levels after 24 hours.