Mineralizing surface is the main target of mechanical stimulation independent of age: 3D dynamic in vivo morphometry
Mineralizing surface is the main target of mechanical stimulation independent of age: 3D dynamic in vivo morphometry
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DOI：
10.1016/j.bone.2014.05.013
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发表时间：
2014-09-01
期刊：
影响因子：
4.1
通讯作者：
Willie, Bettina M.
中科院分区：
文献类型：
--
作者：
Birkhold, Annette I.;Razi, Hajar;Willie, Bettina M.
机械负荷可以通过改变骨形成和骨吸收之间的平衡来增加皮质骨量。随着年龄的增长，骨吸收速度超过形成速度，导致皮质骨量的净损失。皮质骨（再）建模-特别是骨吸收-如何对机械负荷和老化作出反应仍不清楚。在这项研究中，我们研究了机械负荷对皮质骨形成和骨吸收部位调节的年龄相关变化。使用体内微ct，我们确定了三维形成和吸收参数的动力学。为了分析年龄相关的适应性，我们将年轻、成年和老年雌性C57BL/6小鼠的左胫骨循环加载2周。我们的数据显示，在无负荷的肢体中，随着年龄的增长，皮质骨丢失是吸收与形成厚度不平衡的结果，而吸收的表面与形成相当。载荷对地层的影响远大于对再吸收的影响；更具体地说，这种影响是由于机械增产增加了地层表面。这是加载的唯一影响，它保留到老年。在所有年龄组中，吸收厚度与负荷无关。利用这种新颖的图像分析技术，我们首次能够量化皮层（重新）建模和力学适应能力中与年龄相关的变化。最有可能的是，结合体育锻炼和药物治疗与年龄相关的骨质流失是最有效的，如果它们各自作用于（重新）建模过程的不同参数。尽管小鼠和人类在骨骼老化方面存在一些差异，但我们的研究结果表明，老年人的体育锻炼只能对（重新）建模的形成方面产生积极影响。(C) 2014爱思唯尔公司版权所有。
Mechanical loading can increase cortical bone mass by shifting the balance between bone formation and resorption towards increased formation. With advancing age resorption outpaces formation resulting in a net loss in cortical bone mass. How cortical bone (re)modeling - especially resorption - responds to mechanical loading with aging remains unclear. In this study, we investigated age-related changes in the modulation of cortical bone formation and resorption sites by mechanical loading. Using in vivo microCT we determined the kinetics of three dimensional formation and resorption parameters. To analyze age-associated adaptation, the left tibiae of young, adult and elderly female C57BL/6 mice were cyclically loaded for 2 weeks. Our data showed that in the nonloaded limbs, cortical bone loss with age is the result of an imbalance of resorption to formation thickness, while the surface of resorption is comparable to formation. Loading has a much stronger effect on formation than on resorption; more specifically this effect is due to an increase in formation surface with mechanical stimulation. This is the only effect of loading which is conserved into old age. The resorption thickness is independent of loading in all age groups. Using this novel image analysis technique, we were able for the first time to quantify age-related changes in cortical (re)modeling and the adaptive capacity to mechanics. Most likely a therapy against age-related bone loss combining physical exercise and pharmaceuticals is most efficient if they each act on different parameters of the (re)modeling process. Despite some differences in skeletal aging between mice and humans, our results would suggest that physical exercise in old individuals can positively influence only the formation side of (re) modeling. (C) 2014 Elsevier Inc. All rights reserved.