Gao Yuhai, Li Shaofeng, Zhou Yanfeng, Zhou Jian, Shi Wengui, Xie Yanfang, Fang Qingqing, Ren Qian, Chen Keming
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2016 Jun;33(3):520-5.
The present research is to investigate the time effect of sinusoidal electromagnetic fields(SEMFs)at different exposure time on the biomechanical properties in rats,and to find a best time for improving biomechanical properties.Forty female SD rats were randomly divided into five groups,i.e.control group,45 min SEMFs group,90 min SEMFs group,180 min SEMFs group,and 270 min SEMFs group.In addition to the control group,other groups were exposed to 50 Hz and 0.1mT magnetic field every day for the corresponding time periods.After eight weeks,bone mineral density(BMD),bone biomechanics,bone tissue morphology,micro-CT and pathological examination were performed.The results showed that there was no abnormal pathological finding in the experimental groups.In the 90 min SEMFs group,BMD,femur maximum load,elastic modulus,yield strength,trabecular number(Tb.N),trabecular thickness(Tb.Th)and trabecular area(Tb.Ar)percentage were all significantly higher than those in the control group(P<0.01),and trabecular separation(Tb.Sp)was significantly lower than that of the control group(P<0.01).However,for other experimental groups,some indices showed statistical significance compared to the control group(P<0.05),but some did not(P>0.05).This study showed that under 50 Hz and 0.1 mT SEMFs,90 min is the best time that can effectively increase bone mineral density,improve the bone tissue microstructure organization and the biomechanical properties.
本研究旨在探讨不同暴露时间的正弦电磁场（SEMFs）对大鼠生物力学性能的时间效应，并寻找改善生物力学性能的最佳时间。40只雌性SD大鼠随机分为五组，即对照组、45分钟SEMFs组、90分钟SEMFs组、180分钟SEMFs组和270分钟SEMFs组。除对照组外，其他组每天在相应时间段暴露于50Hz和0.1mT的磁场中。八周后，进行骨密度（BMD）、骨生物力学、骨组织形态学、显微CT和病理检查。结果显示，实验组无异常病理发现。在90分钟SEMFs组中，BMD、股骨最大负荷、弹性模量、屈服强度、骨小梁数量（Tb.N）、骨小梁厚度（Tb.Th）和骨小梁面积（Tb.Ar）百分比均显著高于对照组（P<0.01），且骨小梁间距（Tb.Sp）显著低于对照组（P<0.01）。然而，对于其他实验组，与对照组相比，一些指标显示出统计学意义（P<0.05），但一些指标则未显示出统计学意义（P>0.05）。本研究表明，在50Hz和0.1mT的SEMFs作用下，90分钟是能有效增加骨密度、改善骨组织微观结构和生物力学性能的最佳时间。
