The chemical element gadolinium with the atomic number 64 is used as a contrast agent in magnetic resonance imaging. Gadolinium is known to be toxic. However, the combined effects of gadolinium and extremely low frequency magnetic fields, as patients are exposed to during magnetic resonance imaging, have not been investigated by now.
Human lymphocytes were treated with different concentrations of gadolinium (0 mM (control group), 0.2 mM, 0.4 mM, 0.8 mM, 1.2 mM) while exposed to a 60 Hz magnetic field or sham exposed.
Exposure duration: continuous for up to 72 hours
|Exposure duration||continuous for up to 72 hours|
|Setup||two identical, electrically coupled solenoid coils (length 0.30 m, diameter 0.15 m) were wound with 350 turns/m of number-16 bifilar magnet wire on a cylindrical acrylic support; uniformity of the magnetic field in the active exposure volume was ± 2.5%; no significant temperature variations were observed during sham exposure and magnetic field exposure (37 ± 0.5°C)|
|Sham exposure||A sham exposure was conducted.|
|Additional info||sham exposed cultures were tested before the experiments with the same exposure system but with the power supply switched off|
|magnetic flux density||0.8 mT||-||measured||-||-|
Lymphocytes which were treated with gadolinium showed a time-dependent and concentration-dependent significant decrease in cell viability in comparison to the control group. A combined treatment of gadolinium (0.4 mM, 0.8 mM, or 1.2 mM) and 60 Hz magnetic field resulted in a further significant decrease compared to gadolinium treatment alone. The apoptosis rate and the micronucleus formation were significantly increased in cells treated with 1.2 mM gadolinium and a 60 Hz magnetic field compared to the control group and compared to gadolinium alone. The number of DNA strand breaks was significantly increased in gadolinium treated cells (0.2 mM, 0.4 mM, or 0.8 mM) compared to the control. Furthermore, exposure to the 60 Hz magnetic field alone led to a significant increase in the number of strand breaks compared to the control. A combined treatment of gadolinium and exposure to the 60 Hz magnetic field led to a further significant increase in the number of strand breaks compared to gadolinium treatment alone.
In gadolinium treated cells (0.2 mM, 0.4 mM, or 0.8 mM), the level of reactive oxygen species was significantly increased in a concentration-dependent manner compared to the control. A combined treatment with 0.8 mM gadolinium and a 60 Hz magnetic field resulted in higher levels of reactive oxygen species in comparison to gadolinium treatment alone. An addition of N-acetylcysteine prevented this increase.
The data suggest that gadolinium induces DNA damage and apoptotic cell death in human lymphocytes and that these effects could be enhanced by extremely low frequency magnetic fields.