To study the effect of low-intensity laser light (He-Ne, 0.2 mW/cm², 632.8 nm, exposure time 1 min) and of superhigh frequency electromagnetic fields (8.15-18 GHz, 1 µW/cm², exposure time 1 h) on phospho-SAPK/JNK production in mouse spleen lymphocytes.
Cells were treated in three groups: i) exposure to low-intensity laser light ii) exposure to centimeter waves iii) control In a second experiment the same groups were used but cells were pre-incubated with geldanamycin.
The data showed a significant increase of phospho-SAPK/JNK production in lymphocytes after exposure to laser light or microwaves in both cell groups (with/without geldanamycin). Exposure to superhigh frequency electromagnetic fields produced a more significant effect (greater increase) compared to the low-intensity laser light exposure.
The authors concluded that activation of the SAPK/JNK signal pathway plays one of the central roles in cellular stress response to low-power non-ionizing radiation.