Extremely low frequency magnetic fields are discussed as a possible risk factor for neurodegenerative diseases. For this reason, possible molecular responses of a neuronal cell line were investigated in vitro.
Cells were exposed for 1, 3, 24 or 48 hours. Partially, cells were examined directly after exposure and in other cases after incubation for 47 (1 h exposure), 45 (3 h exposure) or 24 (24 h exposure) hours.
|Chamber||cells were mainatined in an incubator with humified atmosphere at 37°C ± 0.3°C and 5% CO2|
|Setup||exposure system consisted of a signal generator, a power amplifier, an oscilloscope to monitor the output signals from the Gaussmeter and the AC MF generator and a 160-turn solenoid (22 cm length, 6 cm radius, 1.25 x 10-5 cm copper wire diameter) generating a horizontal magnetic field; a digital thermometer was placed inside the solenoid to monitor the temperature (37°C ± 0.1°C)|
|Sham exposure||A sham exposure was conducted.|
Oxidative metabolism: The level of reactive oxygen species as well as the protein expression of NOS were significantly increased after short exposure (1 or 3 hours) compared to the sham exposed cells. However, no significant differences were found after longer exposure (24 or 48 h). Similar to this, the gene expression and protein expression of HO-1 were significantly increased after short exposure (3 h) but not after longer exposure (24 or 48 h).
Inflammatory reactions: After short exposure, the gene expression of IL12/IL23 (3 h) and MCP-1 (1 and 3 h) were significantly decreased compared to the sham exposed cells. These alterations were not present after longer exposure. However, the gene expression of the transforming growth factor ß was significantly increased after 24 hours exposure in comparison to the sham exposure.
Serotonin metabolism: The intracellular concentration of serotonin was significantly increased after 1 hour of exposure compared to the sham exposure and significantly decreased after 24 hours. However, the intracellular concentration of 5-HIAA was significantly increased after 1, 3 and 24 hours of exposure in comparison to the sham exposed cells.
The authors summarize, that the balance of oxidative metabolism and between pro- and anti-inflammatory cytokines linked to oxidative stress was maintained but the serotonin metabolism was influenced by the exposure. However, they conclude that the alterations in the human neuroblastoma cell line caused by exposure to the 50 Hz magnetic field are minor compared to cell damage expected to underlie neurodegenerative diseases.