骨の組織・微細構造 ──顕微解剖学的知見──

抄録

Bone is a supporting tissue consisting of a variety of bone cells (osteo blasts,osteoclasts, osteocytes), calcified bone matrix, blood vessels, nerves and so forth. Bone diseases — osteoporosis, bone fracture, arthritis, bone metastasis — often induce bone pain, presumably due to various kinds of nociceptors linked to the signaling in sensory nerves. Nociceptive pain in bone is caused by several stimuli of acid secreted by osteoclasts, physiochemical damaging on peripheral nerves, ATPs, prostaglandins, and so forth. However, precious knowledge on the biological function of bone cells may provide a clue for better understanding on the cellular mechanism of bone pain. In a physiological state, normal bone is always remodeled by balanced osteoclastic bone resorption and subsequent osteoblastic bone formation. Osteocytes connect to neighboring osteocytes and to osteoblasts on the bone surface by means of thin cytoplasmic processes that go through narrow passageways. i.e., osteocytic canaliculi, and thereby building functional syncytia referred to as osteocytic lacunar–canalicular system. Thus, osteocytes are at the center of bone turnover’s mainframe. In this review, we will introduce histological and ultrastructural aspects of bone cells, and give a rough outline of bone pain.