60 rats were divided into four different groups (each group n=15): 1) unexposed control group; 2) ovariectomized only; 3) non-ovariectomized, exposed; and 4) ovariectomized, exposed. Bilateral ovariectomies were performed four days before the beginning of the experiments.
|Setup||two pairs of Helmholtz coils with a diameter of 70 cm, each consisting of 125 turns of insulated copper wire with a diameter of 1.5 mm; coils placed vertically facing each other at a distance of 47 cm; methacrylate cages (43 cm x 42 cm x 15 cm) placed between the coils; rats could move freely inside the cage; exposure system placed inside a 130 cm x 65 cm x 80 cm Faraday cage|
|Sham exposure||A sham exposure was conducted.|
|magnetic flux density||1.5 mT||-||measured||-||-|
Although there was no significant difference in bone mineral density values among the groups before magnetic field exposure, the bone mineral density values increased significantly after six months in the groups 3 (non-ovariectomized, exposed) and 4 (ovariectomized, exposed) and were reduced in group 2 (ovariectomized only) compared to the control group. The concentrations of bone-specific alkaline phosphatase, osteocalcin, and osteoprotogerin in the three groups also changed in a significant way compared to the control group (increase in the exposed groups 3 and 4 indicating increased osteoblast growth and activity and decrease in group 2). The N-telopeptide level decreased in the exposed groups 3 and 4 (indicating a decrease in osteoclast activity) and increased in group 2 compared with the control group.
The data suggest that osteoporosis can be inhibited by extremely low frequency magnetic fields treatments. Extremely low frequency magnetic fields may be useful in the prevention of osteoporosis in ovariectomized rats.