The objective of this study was to examine relationships among a variety of bone characteristics, including volumetric, mineral density, geometric, dynamic mechanical analysis, and static fracture mechanical properties. As MYO9B is an unconventional myosin in bone cells responsible for normal skeletal growth, bone characteristics of wild-type (WT), heterozygous (HET), and MYO9B knockout (KO) mice groups were compared as an animal model to express different bone quantity and quality. Forty-five sex-matched 12-week-old mice were used in this study. After euthanization, femurs were isolated and scanned using microcomputed tomography (micro-CT) to assess bone volumetric, tissue mineral density (TMD), and geometric parameters. Then, a non-destructive dynamic mechanical analysis (DMA) was performed by applying oscillatory bending displacement on the femur. Finally, the same femur was subject to static fracture testing. KO group had significantly lower length, bone mineral density (BMD), bone mass and volume, dynamic and static stiffness, and strength than WT and HET groups (p<0.019). On the other hand, TMD parameters of KO group were comparable with those of WT group. HET group showed volumetric, geometric, and mechanical properties similar to WT group, but had lower TMD (p<0.014). Non-destructive micro-CT and DMA parameters had significant positive correlations with strength (p<0.015) without combined effect of groups and sex on the correlations (p>0.077). This comprehensive characterization provides a better understanding of interactive behavior between the tissue- and organ-level of the same femur. The current findings elucidate that MYO9B is responsible for controlling bone volume to determine the growth rate and fracture risk of bone.

这项研究的目的是检查各种骨骼特征之间的关系，包括体积，矿物质密度，几何形状，动态力学分析和静态断裂力学性能。由于MYO9B是负责正常骨骼生长的骨细胞中的非常规肌球蛋白，因此将野生型（WT），杂合子（HET）和MYO9B敲除（KO）小鼠组的骨特性作为动物模型进行比较，以表达不同的骨量和质量。在这项研究中使用了四十五只性别匹配的12周龄小鼠。安乐死后，分离股骨并使用微型计算机断层扫描（micro-CT）进行扫描，以评估骨体积，组织矿物质密度（TMD）和几何参数。然后，通过在股骨上施加振荡弯曲位移来执行非破坏性动态力学分析（DMA）。最后，对同一股骨进行静态骨折测试。与WT和HET组相比，KO组的长度，骨矿物质密度（BMD），骨骼质量和体积，动态和静态刚度以及强度均显着较低（p <0.019）。另一方面，KO组的TMD参数与WT组的TMD参数相当。HET组的体积，几何和力学性能与WT组相似，但TMD较低（p <0.014）。无损微CT和DMA参数与强度呈显着正相关（p <0.015），而群体和性别对相关性没有联合影响（p> 0.077）。这种全面的表征可以更好地理解同一股骨的组织水平和器官水平之间的交互行为。目前的发现阐明了MYO9B负责控制骨量，以确定骨的生长速率和骨折风险。