Applications of vibrational spectroscopy to assess bone disease and therapeutic interventions are continually advancing, with tissue mineral and protein composition frequently investigated. Here, we used two spectroscopic approaches for determining bone composition in a mouse model of the brittle bone disease osteogenesis imperfecta (OIM) with and without antiresorptive agent treatment (alendronate (ALN) and RANK-Fc). Near infrared (NIR) spectral analysis via a fiber optic probe and Fourier transform infrared spectroscopy using attenuated total reflection (FTIR-ATR) mode were applied to investigate bone composition, including water, mineral and protein content. Spectral parameters revealed differences among the control wildtype (WT) and OIM groups. NIR spectral analysis of protein and water showed that OIM mouse humerii had ~ 50% lower protein and ~ 50% higher overall water content compared to WT bone. Moreover, some OIM treated groups showed a reduction in bone water compared to OIM controls, approximating values observed in WT bone. Differences in bone quality based on increased mineral content and reduced carbonate content were also found between some groups of treated OIM and WT bone, but crystallinity did not differ among all groups. The spectroscopically-determined parameters were evaluated for correlations with gold-standard mechanical testing values to gain insight into how composition influenced bone strength. As expected, bone mechanical strength parameters were consistently up to three-fold greater in WT mice compared to OIM groups, except for stiffness in the ALN-treated OIM groups. Further, bone stiffness, maximum load and post-yield displacement showed the strongest correlations with NIR-determined protein content (positive correlations) and bound-water content (negative correlations). These results demonstrate that in this study, NIR spectral parameters were more sensitive to bone composition differences than ATR parameters, highlighting the potential of this nondestructive approach for screening of bone diseases and therapeutic efficacy in pre-clinical models.

振动光谱学在评估骨病和治疗干预方面的应用不断发展，组织矿物质和蛋白质成分经常被研究。在这里，我们使用两种光谱方法来确定脆性骨病成骨不全症 (OIM) 小鼠模型中的骨成分，无论是否使用抗吸收剂治疗（阿仑膦酸盐 (ALN) 和 RANK-Fc）。通过光纤探头的近红外 (NIR) 光谱分析和使用衰减全反射 (FTIR-ATR) 模式的傅里叶变换红外光谱分析来研究骨骼成分，包括水、矿物质和蛋白质含量。光谱参数揭示了对照野生型 (WT) 和 OIM 组之间的差异。蛋白质和水的 NIR 光谱分析表明，与 WT 骨相比，OIM 小鼠肱骨的蛋白质含量低约 50%，总水含量高约 50%。此外，与 OIM 对照组相比，一些 OIM 治疗组显示出骨水减少，接近在 WT 骨中观察到的值。在一些处理过的 OIM 和 WT 骨组之间也发现了基于矿物质含量增加和碳酸盐含量减少的骨质量差异，但所有组之间的结晶度没有差异。评估光谱确定的参数与金标准机械测试值的相关性，以深入了解成分如何影响骨强度。正如预期的那样，与 OIM 组相比，WT 小鼠的骨机械强度参数始终高出三倍，除了 ALN 治疗的 OIM 组的僵硬。此外，骨刚度、最大负荷和屈服后位移与 NIR 测定的蛋白质含量（正相关）和结合水含量（负相关）的相关性最强。这些结果表明，在本研究中，NIR 光谱参数比 ATR 参数对骨骼成分差异更敏感，突出了这种非破坏性方法在临床前模型中筛查骨骼疾病和治疗效果的潜力。