Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.
Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.
Acta Biomater. 2022 Oct 15;152:345-354. doi: 10.1016/j.actbio.2022.08.064. Epub 2022 Sep 8.
Mineralized collagen fibrils (MCFs) are the fundamental building blocks of bone tissue and contribute significantly to the mechanical behavior of bone. However, it is still largely unknown how the collagen network in bone responds to aging and the disuse normally accompanying it. Utilizing atomic force microscopy, nanoindentation and Raman spectroscopy, age-related alterations in the microstructure and mechanical properties of murine cortical tibia at multiple scales were investigated in this study. The potential difference in the responses of bone to disuse at different ages was studied. The results indicated that the age- and disuse-related alterations in bone initiate from MCFs in the bone matrix. The D-periodic spacing, radial elastic modulus of a single MCF and the mineral-to-matrix ratio on the cortical bone surface were larger in aged mice than in adult mice. Disuse, on the other hand, mainly has a major influence on aged mice, particularly on the morphology and mechanical properties of MCFs, but it only has modest effects on adult bone. These findings revealed insights into the morphological and mechanical adaptation of mineralized collagen fibrils in murine cortical bone to aging and disuse. STATEMENT OF SIGNIFICANCE: Bone is a complex structured composite material consisting of an interwoven framework of collagen fibrils reinforced by mineral particles and embedded in an extrafibrillar mineralized matrix. Utilizing atomic force microscopy, nanoindentation and Raman spectroscopy, this study suggests that the effects of aging, as well as the accompanying disuse, on the morphology and mechanical properties of bone initiate from the mineralized collagen fibril level. More interestingly, the MCF in the bone of aged mice seems to be more sensitive to disuse than that in adult mice. These findings significantly further the current understanding of the adaptation process of bone to aging at the mineralized collagen fibril level and provide direct insights into the physiological response of bone to aging and the abnormal mechanical environment.
矿化胶原纤维（MCF）是骨组织的基本结构单元，对骨的力学性能有重要贡献。然而，骨胶原网络如何应对衰老以及随之而来的废用仍然知之甚少。本研究利用原子力显微镜、纳米压痕和拉曼光谱技术，研究了多个尺度下老年和去负荷小鼠皮质胫骨的微观结构和力学性能的变化。研究了不同年龄的骨对去负荷反应的潜在差异。结果表明，骨基质中的 MCF 是骨与年龄和去负荷相关变化的起点。老年鼠皮质骨表面的 MCF 的 D 周期间距、径向弹性模量和矿化基质比均大于成年鼠。另一方面，去负荷主要对老年鼠产生重大影响，特别是对 MCF 的形态和力学性能，但对成年骨的影响较小。这些发现揭示了矿化胶原纤维在老年和去负荷状态下对鼠皮质骨形态和力学适应性的认识。
骨是一种复杂的结构复合材料，由相互交织的胶原纤维框架组成，由矿物质颗粒增强，并嵌入纤维外矿化基质中。本研究利用原子力显微镜、纳米压痕和拉曼光谱技术，提出衰老以及随之而来的废用对骨形态和力学性能的影响始于矿化胶原纤维水平。更有趣的是，老年鼠骨中的 MCF 似乎比成年鼠骨对废用更敏感。这些发现显著地进一步了解了在矿化胶原纤维水平上骨对衰老的适应过程，并为骨对衰老和异常力学环境的生理反应提供了直接的认识。
