额外负重结合高频率低载荷振动对大鼠骨力学性能的影响

发布时间：2018-10-10 06:09

【摘要】：骨的形态结构与其功能是相适应的。骨所处的力学环境对其形态结构和力学性能有显著影响。除了力学环境外,药物也可以影响骨的形态结构和力学性能。但长期服用药物可能产生副作用。有必要探索非药物、非侵入性疗法对骨骼力学性能的影响。大量先前的探索分别单独地研究了高频率低载荷振动和额外负重训练对骨力学性能的影响。由于这些高频率低载荷振动研究在实验长度、检测的结果和适用条件等存在着差异,在分析其效果时出现了不一致的结论。额外负重训练,即相对日常生活可对骨产生更大应力的运动,有助于骨矿含量的积累和骨量的增加,并影响骨的力学性能。然而,骨在额外负重的同时接受高频率低载荷振动刺激的效果却鲜为人知。本研究有利于研究人员了解额外负重结合高频率低载荷振动对骨的作用机理。本研究旨在从宏观、微观和纳观尺度来探索额外负重结合高频率低载荷振动对生长期雌性大鼠骨的影响。将120只1月龄雌性Wistar大鼠随机平均分为10组,即,静坐组(SED),额外负重为本体体重x%的负重组(WBx,x=5,12,19,26),基础振动组(V),和额外负重为本体体重x%同时振动的负重振动组(Vx,x=5,12,19,26)。振动的频率和加速度分别设为45 Hz和0.3 g。实验进行12周,每周7天,每天15 min。在实验开展前一天,准确测得大鼠体重,从而确定第一周大鼠所负背包的重量。随后,在每周的周末测量大鼠的体重,并重新为背包配重。12周后,大鼠处死,采集血清和左侧股骨。定量分析血清中的抗酒石酸酸性磷酸酶(Tartrate-resistant phosphatase 5b,TRAP5b)、碱性磷酸酶(Alkaline phosphatase,ALP)、钙(Calcium,Ca)和磷(Phosphorus,P)的含量。对于得到的左侧股骨,通过三点弯曲力学实验来检测其宏观力学性能;通过计算机显微断层扫描(Micro-computed tomography,micro-CT)来评估其股骨头松质骨和股骨干皮质骨的微观结构;利用纳米压痕测试技术在纳观尺度测试骨材料力学特性。研究结果表明,SED组的宏观力学性能,微观结构和纳观的材料力学性能较好;V19组的破坏载荷显著低于SED组(P0.05);Vx(x=5,12,19,26)组的微观结构较差,Vx(x=5,12,19,26)组中血清的TRAP5b含量显著高于SED组(P0.05);相比WB26,V26组的纳观材料力学性能较好。SED组体重最高,且显著高于V5组,V19组和V26组(P0.05)。本研究得到以下结论:(1)额外负重结合高频率低载荷振动未对生长期骨的微观形态结构产生积极作用;同时,随着负重的增加,骨的微观形态结构受到的负面影响较为严重。只进行额外负重对生长期骨微观形态结构影响不大;随着额外负重的增加,微观形态结构参数会受到一定的影响,但不足以导致宏观力学性能出现显著性变化。(2)额外负重结合高频率低载荷振动未能提高骨纳观尺度的力学性能。但额外负重较高时,如负重体重的26%,额外负重结合高频率低载荷振动相对于单独的振动刺激更有利于提高骨材料纳观尺度的力学性能。(3)适当额外负重结合高频率低载荷振动有助于降低体重。体重减少不仅影响骨密度(Bone mineral density,BMD),同时也对微观结构参数骨体积分数(Bone fraction,BV/TV),骨小梁厚度(Trabecular thickness,Tb.Th)和骨小梁分离度(Trabecular separation,Tb.Sp)产生了影响。
[Abstract]:The morphological structure of bone is suitable for its function. The mechanical environment at the bone has a significant effect on its morphological structure and mechanical properties. In addition to the mechanical environment, the drug can also influence the morphological structure and mechanical properties of the bone. But long-term administration may have side effects. It is necessary to explore the effect of non-drug and non-invasive therapy on the mechanical properties of bone. The effects of high frequency low load vibration and extra load training on the mechanical properties of bone were studied in a large number of previous studies. Because these high-frequency low-load vibration studies differ in the length of experiment, the result of the test and the applicable conditions, there are different conclusions in the analysis of the effect. The additional weight-bearing training, i.e., relative daily life can generate greater stress to the bone, contributes to the accumulation of bone mineral content and the increase of bone volume, and affects the mechanical properties of the bone. However, the effect of receiving high-frequency low-load vibration stimulation at the same time of extra weight is little known. This study is useful for researchers to understand the mechanism of additional weight-bearing and high-frequency low-load vibration on bone. The purpose of this study was to explore the effects of additional weight-bearing combined with high-frequency low-load vibration on bone in growth phase from macroscopic, microscopic and nano-scales. Twenty-one-month-old female Wistar rats were randomly divided into 10 groups, namely, sedentary group (SED), negative recombination (Wbx, x = 5, 12, 19, 26), basic vibration group (V), and weight-bearing vibration group with additional weight (x = 5, 12, 19, 26). The frequency and acceleration of the vibration were 45 Hz and 0.3 g, respectively. The experiment was carried out for 12 weeks, 7 days a week, 15 minutes a day. The weight of the rat was accurately measured the day before the experiment to determine the weight of the negative backpack in the first week. Subsequently, the body weight of the rats was measured at the weekend of the week and re-weighed for the backpack. After 12 weeks, rats were sacrificed, serum and left femur were collected. The contents of anti-tartaric acid phosphatase (5b, TRAP5b), alkaline phosphatase (ALP), calcium (Callum, Ca) and phosphorus (P) in serum were analyzed quantitatively. For the left femur obtained, the macroscopic mechanical properties of femoral head were examined by three-point bending mechanics experiment, and the microstructure of femoral head cancellous bone and femoral shaft cortical bone was evaluated by micro-computed tomography (micro-CT). Using nano-indentation test technology to test the mechanical properties of bone materials at the nano-view scale. The results showed that the macroscopic mechanical properties, microstructure and nano-view mechanical properties of SED group were better than that of SED group (P0.05). The microstructures of group V19 (x = 5, 12, 19, 26) were poor, and the content of TRAP5b in serum was significantly higher than that in SED group (P0.05). The mechanical properties of nano-view materials in V26 group are better. The body weight of SED group was highest and significantly higher than that in V5 group, V19 group and V26 group (P0.05). The results obtained in this study: (1) The additional weight-bearing and high-frequency low-load vibration did not play an active role in the microstructure of growth phase bone; meanwhile, with the increase of weight, the microstructure of bone was negatively affected. The effect of extra load on the microstructure of growth phase bone is not big; with the increase of extra weight, the micro-morphological structure parameters will be affected, but not enough to cause significant change in macroscopic mechanical properties. (2) The high-frequency low-load vibration of extra weight load failed to improve the mechanical properties of the bone nano-scale. However, when the extra load is higher, such as 26% of weight bearing weight, the additional weight-bearing combined with high-frequency low-load vibration is more favorable for improving the mechanical properties of the nano-scale of bone material. (3) Appropriate additional loading, combined with high frequency low load vibration, helps to reduce body weight. Body weight reduction not only affects bone mineral density (BMD), but also affects microscopic structure parameters bone volume fraction (BV/ TV), bone small beam thickness (Tb. Th) and bone trabecula separation (Tb. Sp).
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R318.01

【相似文献】