50Hz 1.8mT正弦交变电磁场通过促进骨形成抑制尾吊大鼠的骨量丢失

摘要

目的 探究50Hz 1.8mT正弦交变电磁(sinusoidal electromagnetic fields,SEMFs)是否能抑制尾吊(hind-limb suspension,HLS)所致大鼠的骨量丢失.方法 30只雌性SD大鼠(180±10)g,分为3组,每组10只,分别为对照组、HLS组和HLS+SEMFs组.除对照组外,HLS组和HLS+SEMFs组大鼠进行尾吊,之后,HLS+SEMFs组大鼠每天进行1.5h 50Hz 1.8mT正弦交变电磁场干涉.4w后处死全部大鼠,对各组大鼠进行重要脏器的器官指数计算和病理学观察、离体骨密度检测、骨生物力学分析和骨形态计量学分析以及Micro-CT扫描.结果 实验期间各组大鼠的体重及重要脏器的器官指数差异无统计学意义(P＞0.05),脏器病理学观察未见异常变化;骨密度结果显示,SEMFs有效提高股骨和椎骨的离体骨密度;生物力学实验表明,SEMFs减轻了HLS引起的股骨和椎骨力学性能的降低.此外,SEMFs能增加骨钙素(osteocalcin,OC)含量,并且对抗酒石酸酸性磷酸酶5b(tartrate-resistant acid phosphatase 5b,TRACP-5b)具有一定的抑制作用;Micro-CT结果显示,SEMFs部分抑制HLS造成的松质骨骨微结构的减少,相比HLS组,骨小梁数、骨小梁厚度、骨小梁面积显著升高,且分离度下降;骨组织形态学分析同样表明SEMFs改善了松质骨骨微结构的恶化.结论 50Hz 1.8mT SEMFs能抑制HLS所致大鼠的骨量丢失,其可能机制是具有抑制骨吸收和提高骨形成的双重活性,这将为电磁场治疗骨质疏松症的临床应用提供依据.%Objective To explore whether sinusoidal electromagnetic field (SEMFs) can promote bone microstructure, bone strength and bone metabolism of hind-limb suspension (HLS) osteoporosis model.Methods A total of 30 female SD rats (180 ± 10 g body weight) were divided into control group, HLS group and HLS +SEMFs group.HLS+SEMFs group was treated daily for 1.5 hours at 50 Hz with 1.8 mT sinusoidal electromagnetic field interference and the rats were sacrificed after 4 weeks.Bone mineral density (BMD) and biomechanics of rat femur and vertebrae were measured.The levels of serum osteocalcin (OC) and tartrate-resistant acid phosphatase 5b (TRACP 5b) were determined by ELISA.The microstructure of cancellous bone was analyzed by micro-CT.The microstructure of left tibia was observed after picric acid staining.IPP 6.0 software was used to analyze trabecular bone parameters.The organ paraffin embedded sections were subjected to toxicological analysis by HE staining to evaluate the side effects of the electromagnetic field.Results There were no significant differences between the groups in body weight and organ coefficient during the experiment, and there were no abnormal pathological findings.The result showed that SEMFs could improve the bone mineral density of femur and vertebra after 4 weeks.Biomechanical experiments showed that SEMFs reduced the decrease of femoral and vertebral mechanical properties induced by HLS.In addition, SEMFs increased OC content and inhibited TRACP 5b.Micro-CT result showed that SEMFs partially inhibited the decrease of microstructure of cancellous bone caused by HLS.Compared with HLS group, trabecular number, trabecular thickness and trabecular bone area significantly increased, and the trabecular separation significantly decreased.Bone histomorphometric analysis also showed that SEMFs improved the microstructure of cancellous bone.Conclusion SEMFs alleviate bone loss caused by simulated microgravity in hind limbs by promoting bone formation and inhibiting bone resorption, thus SEMFs may be a potential biophysical treatment for osteoporosis.