【作者】 余雷；

【导师】 罗二平；

【作者基本信息】 第四军医大学 ， 生物医学工程， 2004， 硕士

【摘要】 实验目的：随着生物医学工程的发展，低强度复合脉冲电磁场（pulsing electromagnetic fields，PEMFs）治疗骨质疏松以其独特的优势正越来越多地引起人们的重视并运用于实践。近年来国外地一些研究已显示PEMFs可提供一种安全、有效地抑制甚至逆转骨质疏松的效果，使骨量增加而不破坏骨的重建过程。目前虽然应用脉冲电磁场在治疗骨质疏松中取得了成功，但是所用的参数，诸如频率、强度、脉冲等各不相同，到目前还没有证明哪种参数配置为最佳，对电磁场作用机理的解释也还不透彻。 本课题主要研究固定频率下不同强度低强度脉冲电磁场（PEMFs）对去卵巢大鼠骨质疏松的影响，通过实验定量分析动物模型的骨密度和骨形态计量学指标，深入研究电磁场对骨质疏松作用的确切机理，依据试验结果进行统计学分析，从而确定电磁场的最佳强度范围和作用时间，为骨质疏松的预防和治疗提供新的思路和理论依据。 实验方法： 1、设计改进低强度脉冲电磁场电路，通过大量试验选择输出为15Hz准脉冲群，5ms脉冲群延时的刺激波形，磁场强度从（0—12）×10^-4T连续可调，并具有定时功能，线圈直径为100、150、200mm。 第四军医大学硕士学位论文 2、预防组实验。将64只雌性大鼠随机分为8组:正常对照组、去势组、2 x10一勺磁场照射组、4x1o一4T磁场照射组、sx10一勺磁场照射组、4 x 10一勺磁场照射夜晚组、药物治疗组、4x10--4T磁场照射同时药物治疗组。将除正常组外的所有其他组进行去卵巢手术，在不同强度磁场环境中饲养2个月。测定全身骨密度（BMD），并进行骨形态计量。 3、治疗组实验。将64只雌性大鼠随机分为8组:正常对照组、去势组、2 xIO一4T磁场照射组、4xlo一勺磁场照射组、sx一。一4T磁场照射组、loxlo一4T磁场照射组、4xlo一4T磁场照射夜晚组、药物治疗组。将除正常组外的所有其他组进行去卵巢手术，正常喂养两周，然后在不同强度磁场环境中饲养2个月处死所有动物。测定全身骨密度（BMD），并进行骨形态计量。 结果: 1、预防组在经过2个月的电磁场治疗后，处死大鼠。与正常对照组比较，去势组骨密度明显降低，骨显微结构出现了病理改变。在各种磁场强度下大鼠的骨密度及骨形态计量参数相对正常对照组均无显著改变，8 x 10一勺磁场照射组、药物治疗组和4x10--4T磁场照射同时药物治疗组差异相对于其余3组不明显。通过病理切片可见8 x 10一勺磁场照射组、药物治疗组和4x10--4T磁场照射同时药物治疗组较2 x 10一勺磁场照射组、4x 10一4T磁场照射组、4 x 10一4T磁场照射夜晚组骨小梁增加更多，而且分布有序，相互连接成网，骨髓腔面积亦显著减小。 2、治疗组去势后各组大鼠骨密度明显降低，骨显微结构出现了病理改变。经过2个月的电磁场治疗，在各种磁场强度下大鼠骨密度均比去势组有显著改善，在各种磁场强度下大鼠骨密度及骨形态计量参数相对去势组均有不同程度的增加，且差异具有统计学意义。通过病理切片可见2 x 10一勺磁场照射组、4x 10--4T磁场照射组、4 x 10--4T磁场照射夜晚组和 10x10--4T磁场照射组骨小梁较多，较粗，分布有序。8 xlo一勺磁场照射组、药物治疗组较其他组骨小梁分布更有序，相互连接成网，骨髓腔面积亦显著 第四军医大学硕士学位论文减小，接近正常组效果。 结论:PEMFs对去卵巢大鼠的骨质疏松症有一定的预防和治疗作用，但对机体的作用存在着频率、场强、时间及脉冲宽度等参数的窗口效应，另外实验环境（个体差异、照射系统和外围杂散场等等）影响实验结果及实验的可重复性。在频率一定的情况下，对于绝经大鼠的预防和治疗效果15Hz双向准脉冲群电磁场在sx10一勺时效果最为显著，另外对于大鼠白天的预防和治疗效果优于夜晚治疗。更多还原

【Abstract】 Objective: With the development of Biomedical engineering, The treatment of osteoporosis in pulsing electromagnetic fields is attached more importance than ever and used in clinic because of the advantage of PEMFs in osteoporosis. In recent years many overseas research results show that PEMFs can prevent even reverse osteoporosis safely and effectively, it can increase the sum of bone without destroying the rebuilding of bone. Although we succeed in treating osteoporosis with PEMFs at present, the parameter of PEMFs we are using such as frequency, intensity, impulse is different, we cannot find the best parameter of PEMFs and cannot fully explain the effects of PEMFs.This experiment is to observe the effects of osteoporosis rats in different intensity and same frequency PEMFs . Through the experiment quantificationally analyze BMDs of experiment animals and histomorphometric measurement and calculations of distal femur and biomechanics characteristics and study the mechanism of PEMFs on prevention of osteoporosis. Through the experiment results makestatistic analysis and seek the best parameter for treatment.Methods:1 A PEMFs circuit was designed and improved. The outputs of PEMFs were sub-impulse groups with frequency of 15Hz and delay time of 5 ms through many experiments. The intensity of PEMFs could be continuously adjusted from 0 to 12 X 10-4T. This circuit had the function of timing. The diameter of winding was 100,150,200mm.2 The prevent experiment was started. Sixty-four female Sprague-dawley rats were divided randomly to 8 groups :normal control ; ovariectomized ; 2X10-4T PEMFs treatment ; 4X10-4T PEMFs treatment ; 8X10-4T PEMFs treatment; 4X10-4T PEMFs treatment at night ; drug treatment ;4 X 10-4T PEMFs and drug treatment. All groups except normal control group were ovariectomized. Then all groups were bred with the condition of different intensity for two months. BMD were measured by X-ray absooptionetry and histomorphometry on the bone were observed.3 The therapy experiment was started. Sixty-four female Sprague-dawley rats were divided randomly to 8 groups :normal control ; ovariectomized ; 2X10-4T PEMFs treatment ; 4X10-4T PEMFs treatment ; 8X10-4T PEMFs treatment; 10X10-4T PEMFs treatment; 4X10-4T PEMFs treatment at night; drug treatment. All groups except normal control group were ovariectomizedAU those were bred normally for two weeks and then were bred with the condition of different intensity for two months. BMD were measured by X-ray absooptionetry and histomorphometry on the bone were observed.Results:1 After all the prevent group were irradiated two months, all rats were made death .Compared with normal control group, BMDs of ovariectomized group failed significantly and the microstructuresalso pathologically changed. In all different intensity PEMFs BMDs of rats and histomorphometric measurement and calculations of distal femur and biomechanics characteristics were all not changed significantly compared with normal control group. The differences between normal control group and 8X10-4T PEMFs treatment group ,drug treatment group or 4X 10-4T PEMFs and drug treatment group were not more significant than 2X10-4T PEMFs treatment group, 4 X10-4T PEMFs treatment and 4 X 10-4T PEMFs treatment at night group. Through the pathological slices of bones, we could see that 8 X 10-4T PEMFs treatment group ,drug treatment group or 4 X 10-4T PEMFs and drug treatment group incrased more little girder , arranged more orderly and joined together to nets than other groups ,and the marrow areas of these groups decreased more significantly than other groups too.2 After ovariectomized, BMDs of all therapy group failed significantly and the microstructures also pathological changed. Through two months irradiation, in all different intensity PEMFs BMDs of rats and histomorphometric measurement and calculations of distal femur and biomechanics characteristics were all changed significantly compared with ovariectomized group. The differences between ovariectomized group and 8 X更多还原