低强度脉冲电磁场对去卵巢大鼠不同部位骨密度的影响

目的 探讨低强度脉冲电磁场(PEMFs)对去势雌性大鼠不同部位骨密度的影响.方法 30只10月龄雌性SD大鼠随机分为3组:一组去势造模(造模组),另一组行假手术(空白组),第三组去势造模后暴露于50 Hz、0.16 mT的磁场环境下60 min/d,共90天(磁疗组).实验期间动态观察大鼠全身及颅骨骨密度,期满处死后测定血清雌二醇水平及骨密度.结果 ①空白组雌激素水平和子宫系数均显著高于其他两组(P<0.01);②至60天时,空白组、磁疗组的颅骨骨密度显著高于造模组(P<0.05),全身骨密度在90天时才出现统计学意义(P<0.05);③与空白组和磁疗组相比,造模组椎体骨密度(P<0.01)比腰椎骨密度(P<0.05)差异更显著,磁疗组股骨骨密度虽较造模组有所上升但差异未达到统计学意义.结论 全身骨密度与颅骨骨密度结合可有效评估大鼠活体骨密度动态变化;PEMFs对因去势造成的骨密度下降有明显抑制作用,且对不同部位骨密度影响程度不同;采用去椎弓的单一椎体为骨密度衡量点能更为敏感的反映治疗效果.

Effect of low intensify pulsed electromagnetic fields on bone mineral density of different anatomic region in ovariectomized rats

Objective To explore the effect of low intensify pulsed electromagnetic fields on bone mineral density of different anatomic region in ovariectomized rats.Methods Thirty 10-month-old female Sprague-Dawley rats were randomly divided into three different groups: ovariectomized control group (OVX group), normal control group (SHAM group) and pulsed electromagnetic fields exposing group (PEMFs group). All rats were subjected to bilateral ovariectomy except those in SHAM group, and the PEMFs group were exposed to pulsed electromagenetic fields with frequency 50 Hz, peak magnetic induction density 0.16 mT and exposure time 60 minute per day. In the experimental period, bone mineral density (BMD) of general and cranioaural BMD were observed dynamically, eventually, the level of estradiol and the BMD were measured.Results ①In the SHAM group, the level of estradiol and the coefficient of uterus were significantly higher than other two groups(P<0.01);②Compared with SHAM group and PEMFs group, the cranioaural BMD of OVX group were decreased significantly on the 60th day (P<0.05), while the significantly difference of general BMD was detected until the 90th day (P<0.05);③The difference in centrum vertebrae BMD of OVX group were more markedly than in lumbar vertebrae of BMD compared with SHAM group and PEMFs group, the femoral BMD of PEMFs group rose compared with OVX group, but the distinction did not reach the statistical significance.Conclusion Combining general BMD with cranioaural BMD can accurately assess dynamic variation on the BMD of alive rats; This pulsed electromagnetic fields could suppress the reduction of BMD conspicuously in bilateral ovariectomized rats, at the same time, they have different effect on BMD of different anatomic region; It will reflect the changes in bone masses with good precision by measuring the pyramidal BMD.