The Effect Of Low Frequency Pulsed Electromagnetic Fields On Osteoporosis In Ovariectomized Rats

Objective: To observe the effects of low frequency pulsed electromagnetic fields (PEMFs)on blood biochemical indices, bone mineral density and histomorphology inovariectomized rats, so as to find out the therapeutic effect of PEMFs on ovariectomyinduced osteoporotic rats and the optimal daily treatment time. Methods: Thirty-twofemale three months Sprague-Dawley rats were randomly divided into four groups (n=8):Sham group (no PEMFs treatment), OVX group (no PEMFs treatment), PEMFs Ⅰ group(PEMFs treatment at5.4mT intensity with12Hz frequency,2hours per day for12weeks),PEMFs Ⅱ group (PEMFs treatment at5.4mT intensity with12Hz frequency,4hours perday for12weeks). All the rats were subject to bilateral ovariectomy except those in theSham group. After12weeks, the changes of blood biochemical indices, the bone mineraldensity and histomorphometry of femur were assessed after PEMFs therapy. Result:(1)The blood biochemical indices: Compared with the OVX group, the concentration of serumCa, P and ALP decreased obviously in PEMFs Ⅰ/Ⅱ groups (p<0.01), the Ca and Pconcentration closed to the Sham group, the ALP concentration was lower than the Shamgroup significantly(P<0.01);(2) The bone mineral density of femur: Compared with theOVX group, the values of bone mineral density of femur increased obviously in PEMFsⅠ/Ⅱ groups (p<0.01), closed to the Sham group;(3) Histomorphometry of femur:Compared with the OVX group, the Trabecular Area (%Tb.Ar), Trabecular Width (Tb.Wi),Trabecular Number (Tb.N) increased obviously(p<0.01), the Trabecular Seperation (Tb.Sp)decreased obviously in PEMFs Ⅰ/Ⅱ groups (p<0.01), all closed to the Sham group. But the difference of all the parameters was not significant between PEMFs Ⅰ/Ⅱ groups(P>0.05). Conclusion: Low frequency pulsed electromagnetic fields can improve theserum bone metabolism, prevent the bone mineral density decrease, ameliorate themicro-structure of the bone, make them close to the normal level, indicating that thePEMFs has positive therapeutic effect on ovariectomy-induced osteoporotic rats; UsingPEMFs therapy2hours or4hours per day, make the same effect.