Effect of pulsed electromagnetic fields on ovariectomized rats

Sixty Sprague-Dawley rats (10 months old, body weight 400 +/- 25 g) were ra ndomized into six groups of 10 animals each, to study the effect of pulsed electromagnetic fields (PEMFs) on the treatment of ovariectomized osteopeni c rats. One group was used as baseline (Baseline). Four groups were ovariec tomized, and another was sham-operated (Sham). Three ovariectomized groups were given three different PEMFs of the same intensity (7 mT) for 1 h a day for 16 weeks. Groups OVX-50 and OVX-100 were subjected to monodirectional sine-wave PEMFs with different frequencies (50 and 100 Hz), while Group OVX -72 was subjected to 72-Hz bidirectional square-wave PEMFs. Group Sham and an unexposed ovariectomized group (OVX) were used as therapy controls. Diff erences were observed for densitometric, biomechanical, and histomorphometr ic data (p < 0.005), particularly between the ovariectomized groups and the non-ovariectomized groups. Monthly food consumption (MFC) showed significa nt decreases (p < 0.05) in Groups OVX, OVX-72, and OVX-100, as monthly pond eral variation (MPV) showed significant differences (p < 0.005), particular ly Group OVX-72 vs. Group OVX. However, none of the PEMFs used produced an amelioration of castration-induced osteopenia by changing the balance betwe en bone resorption and formation. As opposed to PEMFs at 50 and 100 Hz, the effect on bone of PEMFs at 72 Hz could have been hidden by systemic applic ation of an instrument conceived for local therapy only.