Effect of pulsed electromagnetic fields of different treatment time on serum estradiol and bone calcium content of femur in ovariectomized rats

Objective:To observe the effect of pulsed electromagnetic fields(PEMFs) of different treatment time on serum estradiol and bone calcium content of femur in ovariectomized rats,so as to find out the best effective treatment time. Method:Fifty female SD rats were randomly divided into five groups:①SHAM control (no PEMFs treatment),②OVX control(no PEMFs treatment),③OVXⅠ(PEMFs treatment at 8Hz frequency with 3.8mT intensity,20min daily for 30 days),④OVXⅡ(PEMFs treatment at 8Hz frequency with 3.8mT intensity,40min daily for 30 days),and ⑤OVXⅢ(PEMFs treatment at 8Hz frequency with 3.8mT intensity,60min daily for 30 days). All rats were subjected to bilateral ovariectomy except those in the SHAM control group. Serum estradiol(E2) and bone calcium content of femur were assessed on the 30th days after PEMFs treatment. Result:The E2 values of the SHAM control group were significantly higher than that of the other 4 groups(P0.05 or P0.01),but the difference in E2 values was not significant among the other 4 groups(P0.05). The bone calcium contents of the OVX control group were significantly lower than that of the other 4 groups(P0.01),but the difference of calcium contents was not significant among the other 4 groups (P0.05).Conclusion:Under certain intensity(3.8mT) and frequency (8Hz),PEMFs of the three different treatment time can′t significantly improve serum estradiol level in ovariectomized rats. PEMFs of the three different treatment time can significantly maintain bone calcium content of femur approximately to the normal level in ovariectomized rats,but among the three groups,the difference is not significant. It shows that PEMFs have the same effect of maintaining bone calcium content with no correlation of increasing the treatment time within the range of 20-60min in ovariectomized rats.