Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1, Yamada-Oka, Suita, Osaka 565-0871, Japan.
Bone. 2012 Oct;51(4):741-7. doi: 10.1016/j.bone.2012.07.003. Epub 2012 Jul 14.
Recently, there have been remarkable advances in medical techniques for regenerating bone defects. To determine the degree of bone regeneration, it is essential to develop a new method that can analyze microstructure and related mechanical function. Here, quantitative analysis of the orientation distribution of biological apatite (BAp) crystallites by a microbeam X-ray diffractometer system is proposed as a new index of bone quality for the evaluation of regenerated bone microstructure. Preferential alignment of the BAp c-axis in the rabbit ulna and skull bone, regenerated by controlled release of basic fibroblast growth factor (bFGF) was investigated. The BAp c-axis orientation was evaluated by the relative intensity between the (002) and (310) diffraction peaks, or the three-dimensional texture for the (002) peak. It was found that new bone in the defects was initially produced without preferential alignment of the BAp c-axis, and subsequently reproduced to recover towards the original alignment. In other words, the BAp density recovered prior to the BAp orientation. Perfect recovery of BAp alignment was not achieved in the ulna and skull defects after 4 weeks and 12 weeks, respectively. Apparent recovery of the macroscopic shape and bio-mineralization of BAp was almost complete in the ulna defect after 4 weeks. However, an additional 2 weeks was required for complete repair of BAp orientation. It is finally concluded that orientation distribution of BAp crystallites offers an effective means of evaluating the degree of microstructural regeneration, and also the related mechanical function, in regenerated hard tissues.
最近，在再生骨缺损的医学技术方面取得了显著的进展。为了确定骨再生的程度，开发一种能够分析微观结构和相关机械功能的新方法至关重要。在这里，提出了一种使用微束 X 射线衍射仪系统定量分析生物磷灰石（BAp）晶体取向分布的新方法，作为评估再生骨微观结构的骨质量新指标。研究了通过碱性成纤维细胞生长因子（bFGF）控制释放来再生的兔尺骨和颅骨中 BAp 晶轴的优先取向。通过（002）和（310）衍射峰之间的相对强度或（002）峰的三维织构来评估 BAp c 轴取向。结果发现，最初在缺陷中产生的新骨没有 BAp c 轴的优先取向，随后会恢复到原始取向。换句话说，BAp 密度在 BAp 取向之前恢复。在 4 周和 12 周后，分别在尺骨和颅骨缺陷中，BAp 取向没有完全恢复。在 4 周后，尺骨缺陷中 BAp 取向的宏观形状和生物矿化的明显恢复几乎完成。然而，还需要另外 2 周的时间才能完全修复 BAp 取向。最后得出结论，BAp 晶体取向分布为评估再生硬组织的微观结构再生程度以及相关机械功能提供了有效的手段。
