不同强度正弦交变电磁场对大鼠骨密度及骨形态计量学的影响

目的 ：研究50 Hz不同强度正弦交变电磁场（sinusoidal electromagnetic fields,SEMFs）对SD大鼠骨密度和骨形态计量学的影响。方法：将30只雌性SD大鼠随机分为3组：A组（正常对照组）,B组（0.1 m T磁场组）和C组（0.6 m T磁场组）。除对照组外,分别给予各磁场组每日3 h的磁场干预。实验8周后处死大鼠,用双能X线骨密度仪检测各组大鼠全身、股骨及椎体骨密度,并对左侧胫骨及椎体L4分别进行骨组织静态和动态分析评价。结果：与A组相比,B组大鼠全身、股骨和椎体骨密度显著增加;股骨和椎体骨小梁面积百分数、骨小梁数量和骨小梁宽度显著增加,骨小梁分离度明显降低;观察双标记有明显变化。C组骨小梁数目与A组相比差异有统计学意义,其余指标差异均无统计学意义。结论：50 Hz 0.1 m T磁场强度的正弦交变电磁场,能够有效增加大鼠骨密度,改善大鼠的骨组织微结构,促进骨形成。

Effect of different-intensity SEMFs on bone mineral density and histomorphometry in SD rats

Objective: To investigate the effects of different-intensity sinusoidal electromagnetic fields(SEMFs) on bone mineral density(BMD) and histomorphometry in SD rats.Methods: Thirty female SD rats were randomly divided into three groups:group A(a control group),group B(0.1 mT group) and group C(0.6 mT group). The rats in group B and C were exposed to 50 Hz SEMFs 3 hours each day. However,the magnetic intensity was different between group B and group C:0.1 mT for group B and 0.6 mT for group C. After 8 weeks,all the animals were killed. Changes of BMD and histomorphometric properties were observed.Results: Compared with group A,the BMD of whole body,femur and vertebrae of rats in group B increased significantly;the area percentage,number and width of bone trabeculae in vertebrae and femur of rats in group B were larger than those of group A;but the resolution of bone trabeculae of rats in group B was lower than that of group A. The trabecular number in group C rats were significantly decreased,compared with that in group A rats. The outcome of double fluorescence labeling in group B was found to be significantly different with that in group A. But the difference between rats in group A and C was not significant.Conclusion: This study demonstrates that 50 Hz 0.1 mT SEMFs can increase BMD,improve bone tissue microstructure and,promote bone formation.