Additionally, the findings of Lin et al. should be confirmed, who claimed that the hsp70 promoter responses to magnetic fields.
A plasmid that includes the luciferase gene and partially the hsp70 promoter was electro-transfected in vivo into the quadriceps muscle (skeletal muscle of the femur) of mice.
Four groups were examined (n=3 per group): 1.) non-transfected mice (negative control), 2.) transfected mice (plasmid containing hsp70 promoter), 3.) transfected mice (plasmid without the hsp70 promoter) and 4.) transfected mice (plasmid containing hsp70 promoter) + magnetic field exposure.
|Setup||71 cm long solenoid with a radius of 13.5 cm constructed by 552 turns of 1.3 mm diameter enamel-insulated copper wire; plastic separator placed inside the coil to allow the placement of uncaged mice in the coil; food and water containers also placed inside the coil|
|Sham exposure||A sham exposure was conducted.|
In the quadriceps muscle of exposed mice transfected with the plasmid containing the hsp70 promoter (group 4), the enzyme activity of the luciferase was significantly increased (87.6% when compared to group 2) compared to all other groups.
The authors conclude that exposure to an extremely low frequency magnetic field increased the luciferase gene expression by activation of the hsp70 promoter in the quadriceps muscle of mice.