ラマン分光法・赤外分光法による骨質解析

Bone Cell Biology Assessed by Microscopic Approach. Assessment of bone quality using Raman and infrared spectroscopy.

　骨質とは骨の質を意味し，骨量と共に骨強度に反映される。骨量は骨密度によって数値化することができる 一方，骨質は骨構造，骨基質，石灰化度，マイクロダメージ，骨代謝回転など複数の因子から構成されるため， 単純に数値化することが難しく，複数の因子を同時に計測できる骨質評価法の開発が望まれている。そのよう な中，ラマン分光法と赤外分光法が，骨の成分であるコラーゲンやヒドロキシアパタイトの化学構造に関する 情報を得られる手法として注目されている。特に，イメージング法が開発されてからは，ラマンイメージング， 赤外イメージングによる骨質研究が多数報告されるようになり，新しい骨形態計測法の一つとして期待されて いる。

　Bone quality, which was defined as “the sum total of characteristics of the bone that influence the bone's resistance to fracture” at the National Institute of Health（NIH）conference in 2001, contributes to bone strength in combination with bone mass. Bone mass is often measured as bone mineral density（BMD）and, consequently, can be quantified easily. On the other hand, bone quality is composed of several factors such as bone structure, bone matrix, calcification degree, microdamage, and bone turnover, and it is not easy to obtain data for the various factors. Therefore, it is difficult to quantify bone quality. We are eager to develop new measurement methods for bone quality that make it possible to determine several factors associated with bone quality at the same time. Analytic methods based on Raman and FTIR spectroscopy have attracted a good deal of attention as they can provide a good deal of chemical information about hydroxyapatite and collagen, which are the main components of bone. A lot of studies on bone quality using Raman and FTIR imaging have been reported following the development of the two imaging systems. Thus, both Raman and FTIR imaging appear to be promising new bone morphometric techniques.