Tian Yong-Hui, Li Wen-Yuan, Gao Yu-Hai, Zhou Jian, Chen Ke-Ming, Li Xue-Yan
School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, Gansu, China.
Zhongguo Gu Shang. 2020 Mar 25;33(3):224-9. doi: 10.12200/j.issn.1003-0034.2020.03.007.
To compare effects of low frequency pulsed electromagnetic fields on bone quality in growing rats between 1 h and 1.5 h.
Thirty male SPF SD rats aged 4 weeks selected, which with the average body weight (115.8± 1.5) g, were divided into three groups according to random number table, 10 rats in each group. Control groups put rats into electromagnetic field device with 1.5 h every day, the other two groups put rats in electromagnetic field for 1 h and 1.5 h with a 50 Hz 0.6 mT intensity pulsed. The body weight of rats was weighed every 2 weeks and detected bone mineral density. Rats were sacrificed after 6 weeks to measure bone mineral density and biomechanical value of the right femur and lumbar vertebrae. Serum osteocalcin (OC) and tartrate-resistant acid phosphatase 5b (TRACP 5b) concentrations were determined by ELISA methods. After the magenta-picric acid staining, the micro tissue structure of the right tibia was observed, and the parameters of trabecular bone were analyzed by IPP 6.0 software.
There were no statistical difference in body weight and organ coefficient among each groups at different times. Bone mineral density results showed that the body thickness of the 1.5 h group was significantly increased compared with control group at 6 weeks, and bone mineral density of femoral and vertebra in 1.5 h group were higher than that of in 1 h group. The results of three point femoral bending and vertebral compression test showed that the maximum load value of femur and vertebrae in 1.5 h group increased significantly compared with control group, and the maximum femoral load value in 1.5 h group was significantly higher than that of 1 h group, while there was no difference in elastic modulus values among each groups. Results of serum biochemical indicators showed that level of OC in 1.5 h group was significantly increased compared with control group, and significantly higher than that of 1 h group, while no significant difference in TRACP 5b values among each groups. Bone histomorphometry analysis results showed that there was no statistical difference in trabecular thickness, number and resolution between 1 h group and control group, trabecular bone thickness and number in 1.5 h group were increased, and trabecular bone resolution was decreased; The thickness and number of trabecular bone in 1.5 h group were also significantly increased compared with 1 h group, and the degree of resolution was reduced, and had significant difference between two groups.
Intervention of 50 Hz 0.6 mT low frequency pulsed electromagnetic field for 1.5 h could effectively increase peak bone mineral density and bone microstructure in young rats, enhance biomechanical properties of bone, promote concentration of bone formation markers in rat blood. The results indicating that pulsed electromagnetic field could be used as a good way to prevent and treat osteoporosis.
比较1小时和1.5小时的低频脉冲电磁场对生长发育期大鼠骨质量的影响。
选取30只4周龄雄性SPF级SD大鼠，平均体重（115.8±1.5）g，按随机数字表法分为3组，每组10只。对照组大鼠每天放入电磁场装置中1.5小时，另外两组大鼠分别在强度为50Hz、0.6mT的脉冲电磁场中暴露1小时和1.5小时。每2周称量大鼠体重并检测骨密度。6周后处死大鼠，测量右侧股骨和腰椎的骨密度及生物力学值。采用ELISA法测定血清骨钙素（OC）和抗酒石酸酸性磷酸酶5b（TRACP 5b）浓度。经品红苦味酸染色后，观察右侧胫骨的微观组织结构，并用IPP 6.0软件分析骨小梁参数。
不同时间各组大鼠体重和脏器系数比较，差异均无统计学意义。骨密度结果显示，6周时1.5小时组大鼠的骨皮质厚度较对照组显著增加，1.5小时组股骨和椎体的骨密度高于1小时组。三点弯曲股骨试验和椎体压缩试验结果显示，1.5小时组股骨和椎体的最大载荷值较对照组显著增加，1.5小时组股骨最大载荷值显著高于1小时组，各组弹性模量值比较差异无统计学意义。血清生化指标结果显示，1.5小时组OC水平较对照组显著升高，且显著高于1小时组，各组TRACP 5b值比较差异无统计学意义。骨组织形态计量学分析结果显示，1小时组与对照组骨小梁厚度、数量和分离度比较，差异无统计学意义，1.5小时组骨小梁厚度和数量增加，骨小梁分离度降低；1.5小时组骨小梁厚度和数量较1小时组也显著增加，分离度减小，两组间差异有统计学意义。
50Hz、0.6mT低频脉冲电磁场干预1.5小时可有效提高幼鼠的峰值骨密度和骨微观结构，增强骨的生物力学性能，促进大鼠血液中骨形成标志物浓度升高。结果表明，脉冲电磁场可作为预防和治疗骨质疏松症的良好方法。
