低频正弦交变电磁场对大鼠骨形态和生物力学的影响

Effect of low frequency sinusoidal alternating electromagnetic field on bone morphology and biomechanics in rats

目的探讨低频正弦交变电磁场对大鼠骨密度和生物力学的影响,以为防治骨质疏松提供理论依据。方法将30只大鼠随机分为对照组、0.4 mT正弦交变电磁场组(0.4 mT组)和1.8 mT正弦交变电磁场组(1.8 mT组),磁场频率均为50 Hz,暴露时间为6 h/d,采用影像学技术检测各组股骨和全身骨骨密度的变化,取一段胫骨行苏木精-伊红(HE)染色观察骨形态变化,采用计算机软件测量最大力以及最大力与植入面积的比值(最大切面强度)。结果与对照组比较,0.4 m T组和1.8 mT组的全身骨密度和股骨骨密度均明显升高,骨形态指标骨小梁宽度、数目和骨小梁面积(%)均明显升高,而骨小梁间隙缩小,差异具有统计学意义(P<0.05),其中1.8 mT组上骨小梁数目和全身骨密度的变化明显优于0.4 mT组(P<0.05),而其余指标比较差异无统计学意义(P>0.05)。1.8 mT组最大力和最大切面强度分别为(182.33±32.65)N和(7.12±1.03)N/mm2,低于对照组(P<0.05),但与0.4 mT组比较差异无统计学意义(P>0.05)。结论 1.8 mT正弦交变电磁场可有效提高骨密度,改善骨微观形态和结构,且不影响骨的生物力学,为电磁场预防和治疗临床老年骨质疏松者提供理论依据。

Objective To explore the effect of low-frequency sinusoidal alternating electromagnetic field on bonedensity and biomechanics in rats,so as to provide theoretical basis for the prevention and treatment of osteoporosis.Methods Thirty rats were randomly divided into control group,0.4 mT sinusoidal alternating electromagnetic field group（0.4 mT group）and 1.8 mT sinusoidal alternating electromagnetic field group（1.8 mT group）,the magnetic field frequencywas 50 hz,the exposure time was 6 hours a day,using imaging techniques to detect each group of femur and the change of thewhole body bone density,take a tibial line for HE staining to observe morphological changes,measurement with computersoftware for the most strongly and vigorously with implant area ratio（maximum intensity of cross section）. Results Comparedwith control group,0.4 mT and 1.8 m T group of whole body bone mineral density and the femoral bone mineral density weresignificantly elevated,bone trabecular shape indices width,bone trabecular number and the trabecular bone area（%）weresignificantly increased,and the trabecular bone gap narrowed significant（P〈0.05）,of which 1.8 mT group was obviouslybetter than 0.4 mT group about the number of trabecular bone and the change of the whole body bone mineral density（P〈0.05）,while the rest of the index has no statistical significance difference（P〉0.05）. The maximum strength andmaximum shear strength of the 1.8 mt group were（182.33＋32.65）N and（7.12＋1.03）N/mm^2 respectively,lower than that ofthe control group（P〈0.05）,but the difference was not statistically significant compared with the 0.4 mt group（P〉0.05）.Conclusion 1.8 mT sinusoidal alternating electromagnetic field can effectively increase the bone density,improve the microstructure of bone and structure,and does not affect bone biomechanics. It can provide theoretical basis for clinical senileosteoporosis of prevention and treatment.