School of Veterinary Sciences, University of Bristol , Bristol , UK.
Front Endocrinol (Lausanne). 2014 Oct 1;5:154. doi: 10.3389/fendo.2014.00154. eCollection 2014.
Changing loading regimens by natural means such as exercise, with or without interference such as osteotomy, has provided useful information on the structure:function relationship in bone tissue. However, the greatest precision in defining those aspects of the overall strain environment that influence modeling and remodeling behavior has been achieved by relating quantified changes in bone architecture to quantified changes in bones' strain environment produced by direct, controlled artificial bone loading. Jiri Hert introduced the technique of artificial loading of bones in vivo with external devices in the 1960s using an electromechanical device to load rabbit tibiae through transfixing stainless steel pins. Quantifying natural bone strains during locomotion by attaching electrical resistance strain gages to bone surfaces was introduced by Lanyon, also in the 1960s. These studies in a variety of bones in a number of species demonstrated remarkable uniformity in the peak strains and maximum strain rates experienced. Experiments combining strain gage instrumentation with artificial loading in sheep, pigs, roosters, turkeys, rats, and mice has yielded significant insight into the control of strain-related adaptive (re)modeling. This diversity of approach has been largely superseded by non-invasive transcutaneous loading in rats and mice, which is now the model of choice for many studies. Together such studies have demonstrated that over the physiological strain range, bone's mechanically adaptive processes are responsive to dynamic but not static strains; the size and nature of the adaptive response controlling bone mass is linearly related to the peak loads encountered; the strain-related response is preferentially sensitive to high strain rates and unresponsive to static ones; is most responsive to unusual strain distributions; is maximized by remarkably few strain cycles, and that these are most effective when interrupted by short periods of rest between them.
通过自然方式（如运动）改变加载方式，无需进行截骨等干扰，为骨骼组织的结构-功能关系提供了有用的信息。然而，通过将骨结构的定量变化与直接、受控的人工骨加载产生的骨应变环境的定量变化相关联，在定义影响建模和重塑行为的整体应变环境方面取得了最大的精度。Jiri Hert 在 20 世纪 60 年代引入了使用外部设备对活体骨骼进行人工加载的技术，使用机电设备通过贯穿不锈钢销钉对兔胫骨进行加载。Lanyon 在 20 世纪 60 年代也引入了通过将电阻应变计附着在骨表面来量化运动过程中自然骨应变的技术。在许多物种的各种骨骼中进行的这些研究表明，所经历的峰值应变和最大应变速率具有显著的一致性。在绵羊、猪、公鸡、火鸡、大鼠和小鼠中结合应变计仪器和人工加载进行的实验为应变相关的适应性（再）建模的控制提供了重要的见解。这种多样性的方法在很大程度上被大鼠和小鼠的非侵入性经皮加载所取代，这现在是许多研究的首选模型。这些研究一起表明，在生理应变范围内，骨骼的机械适应性过程对动态应变而不是静态应变有反应；控制骨量的适应性反应的大小和性质与所遇到的峰值载荷线性相关；与静态应变相比，应变相关的反应对高应变速率更敏感，对静态应变不敏感；对异常应变分布更敏感；在非常少的应变循环中达到最大值，并且当它们之间通过短时间的休息来中断时，这些应变循环最有效。
