Yang Haisheng, Bullock Whitney A, Myhal Alexandra, DeShield Philip, Duffy Daniel, Main Russell P
Department of Biomedical Engineering, Faculty of Environment and Life Beijing University of Technology Beijing China.
School of Medicine Indiana University Bloomington IN USA.
JBMR Plus. 2021 Mar 30;5(5):e10489. doi: 10.1002/jbm4.10489. eCollection 2021 May.
Strain magnitude has a controlling influence on bone adaptive response. However, questions remain as to how and if cancellous and cortical bone tissues respond differently to varied strain magnitudes, particularly at a molecular level. The goal of this study was to characterize the time-dependent gene expression, bone formation, and structural response of the cancellous and cortical bone of female C57Bl/6 mice to mechanical loading by applying varying load levels (low: -3.5 N; medium: -5.2 N; high: -7 N) to the skeleton using a mouse tibia loading model. The loading experiment showed that cortical bone mass at the tibial midshaft was significantly enhanced following all load levels examined and bone formation activities were particularly elevated at the medium and high loads applied. In contrast, for the proximal metaphyseal cancellous bone, only the high load led to significant increases in bone mass and bone formation indices. Similarly, expression of genes associated with inhibition of bone formation (e.g., ) was altered in the diaphyseal cortical bone at all load levels, but in the metaphyseal cortico-cancellous bone only by the high load. Finite element analysis determined that the peak tensile or compressive strains that were osteogenic for the proximal cancellous bone under the high load were significantly greater than those that were osteogenic for the midshaft cortical tissues under the low load. These results suggest that the magnitude of the strain stimulus regulating structural, cellular, and molecular responses of bone to loading may be greater for the cancellous tissues than for the cortical tissues. © 2021 The Authors. published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
应变幅度对骨骼适应性反应具有控制作用。然而，关于松质骨和皮质骨组织如何以及是否对不同的应变幅度有不同反应，尤其是在分子水平上，仍存在问题。本研究的目的是通过使用小鼠胫骨加载模型对骨骼施加不同的负荷水平（低：-3.5 N；中：-5.2 N；高：-7 N），来表征雌性C57Bl/6小鼠的松质骨和皮质骨对机械负荷的时间依赖性基因表达、骨形成和结构反应。加载实验表明，在所有检测的负荷水平后，胫骨中轴的皮质骨质量均显著增加，并且在施加的中、高负荷下骨形成活动尤其增强。相比之下，对于近端干骺端松质骨，只有高负荷导致骨质量和骨形成指数显著增加。同样，与骨形成抑制相关的基因（例如）的表达在所有负荷水平下的骨干皮质骨中均发生改变，但在干骺端皮质-松质骨中仅在高负荷下发生改变。有限元分析确定，高负荷下近端松质骨成骨的峰值拉伸或压缩应变显著大于低负荷下中轴皮质组织成骨的应变。这些结果表明，调节骨骼对负荷的结构、细胞和分子反应的应变刺激幅度，松质组织可能比皮质组织更大。© 2021作者。由Wiley Periodicals LLC代表美国骨与矿物质研究学会出版。
