Castillo Alesha B, Alam Imranul, Tanaka Shigeo M, Levenda Jeffery, Li Jiliang, Warden Stuart J, Turner Charles H
Department of Biomedical Engineering, Purdue School of Engineering and Technology, Indiana University School of Medicine, 1120 South Drive, Fesler Hall 115, Indianapolis, IN 46202, USA.
Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa 920-1192, Japan.
Bone. 2006 Nov;39(5):1087-1096. doi: 10.1016/j.bone.2006.04.026. Epub 2006 Jun 21.
Mechanical loading of the skeleton is necessary to maintain bone structure and strength. Large amplitude strains associated with vigorous activity typically result in the greatest osteogenic response; however, data suggest that low-amplitude, broad-frequency vibration results in new bone formation and may enhance adaptation through a stochastic resonance (SR) phenomenon. That is, random noise may maximally enhance bone formation to a known osteogenic stimulus. The aims of this study were to (1) assess the ability of different vibration signals to enhance cortical bone formation during short- and long-term loading and (2) determine whether vibration could effect SR in bone. Two studies were completed wherein several osteogenic loading waveforms, with or without an additive low-amplitude, broad-frequency (0-50 Hz) vibration signal, were applied to the mouse ulna in axial compression. In study 1, mice were loaded short-term (30 s/day, 2 days) with either a carrier signal alone (1 or 2 N sine waveform), vibration signal alone [0.1 N or 0.3 N root mean square (RMS)] or combined carrier and vibration signal. In study 2, mice were loaded long-term (30 s/day, 3 days/week, 4 weeks) with a carrier signal alone (static or sine waveform), vibration signal alone (0.02 N, 0.04 N, 0.08 N or 0.25 N RMS) or combined carrier and vibration signal. Sequential calcein bone labels were administered at 2 and 4 days and at 4 and 29 days after the first day of loading in study 1 and 2, respectively; bone formation parameters and changes in geometry were measured. Combined application of the carrier and vibration signals in study 1 resulted in significantly greater bone formation than with either signal alone (P < 0.001); however, this increase was independently explained by increased strain levels associated with additive vibration. When load and strain levels were similar across loading groups in study 2, cortical bone formation and changes in geometry were not significantly altered by vibration. Vibration alone did not result in any new bone formation. Our data suggest that low-amplitude, broad-frequency vibration superimposed onto an osteogenic waveform or vibration alone does not enhance cortical bone adaptation at the frequencies, amplitudes and loading periods tested.
骨骼的机械负荷对于维持骨结构和强度至关重要。与剧烈活动相关的大幅度应变通常会导致最大的成骨反应；然而，数据表明低幅度、宽频率振动会导致新骨形成，并可能通过随机共振（SR）现象增强适应性。也就是说，随机噪声可能会最大程度地增强对已知成骨刺激的骨形成。本研究的目的是：（1）评估不同振动信号在短期和长期负荷期间增强皮质骨形成的能力；（2）确定振动是否会影响骨中的随机共振。完成了两项研究，其中将几种成骨负荷波形（有或没有叠加的低幅度、宽频率（0 - 50 Hz）振动信号）轴向压缩施加于小鼠尺骨。在研究1中，小鼠短期（每天30秒，共2天）接受单独的载波信号（1或2 N正弦波形）、单独的振动信号[0.1 N或0.3 N均方根（RMS）]或载波与振动信号组合。在研究2中，小鼠长期（每天30秒，每周3天，共4周）接受单独的载波信号（静态或正弦波形）、单独的振动信号（0.02 N、0.04 N、0.08 N或0.25 N RMS）或载波与振动信号组合。在研究1和2中，分别在负荷第一天后的第2天和第4天以及第4天和第29天给予连续的钙黄绿素骨标记；测量骨形成参数和几何形状变化。研究1中载波与振动信号的联合应用导致的骨形成明显大于单独使用任何一种信号（P < 0.001）；然而，这种增加独立地由与叠加振动相关的应变水平增加所解释。当研究2中各负荷组的负荷和应变水平相似时，振动并未显著改变皮质骨形成和几何形状变化。单独的振动未导致任何新骨形成。我们的数据表明，叠加在成骨波形上的低幅度、宽频率振动或单独的振动在测试的频率、幅度和负荷期内不会增强皮质骨适应性。
