[Bone Cell Biology Assessed by Microscopic Approach. Mechanisms of in vivo osteoclastogenesis].

Many new findings about osteoclastogenesis have been provided by in vitro osteoclast culture methods. However, it is necessary to identify genuine in vivo osteoclast precursors and analyze their dynamics in order to completely understand in vivo osteoclastogenesis. Previously, we identified an in vivo osteoclast precursor (qOP : quiescent osteoclast precursors). In this review, the differentiation and movement of qOP will be described based on recent experimental data. Moreover, I will show evidence that the expression level of RANK in qOP is increased in bone tissue, which is an important event for in vivo osteoclastogenesis.