組織内骨細胞の形態変化過程の解明を目指した実験手法の検討

抄録

Bone has an ability to adapt itself to its mechanical environment. This adaptive phenomenon is regulated by bone cells such as osteoclasts, osteoblasts, and osteocytes. Osteocytes are believed to sense mechanical stimuli and transmit biochemical information through intercellular communication. Osteocytes are buried in bone matrix and form a 3D network via cell processes. It has been experimentally suggested that the structure of the osteocyte network is related to mechanical environment. It has been found that the osteocyte network has different structures depending on bone specific diseases such as osteoarthritis, osteoporosis, and osteopetrosis. The elucidation of the osteocyte network formation process under mechanical environment is expected to lead to early detection and treatment of bone specific diseases. However, it remains unclear how the osteocyte network is formed. In this study, we aim at clarifying the relationship between osteocytes within bone matrix and their mechanical environment by the morphometry of osteocytes based on fluorescence imaging and the analysis of the bone specific gene expression (Sost/Sclerostin). To measure the morphological characteristics and the orientational direction, we fluorescently stained actin cytoskeleton and nuclei in osteocytes embeded in a murine long bone. As a result, it was shown that the osteocyte cell bodies are elongated along the longitudinal direction of the long bone. Furthermore, we applied the mechanical loading to bone tissue ex vivo with a three-point bending system, and measured the Sost/Sclerostin expression. The result showed that bone tissues ex vivo change the Sost/Sclerostin expression, depending on the mechanical stimuli.