New insights in osteocyte imaging by synchrotron radiation

Bone health depends on the bone mineral density and mechanical strength, characterised quantitatively andinferred through qualitative parameters such as the trabecular and cortical micro-architecture, and other parametersdescribing the bone cells. Among these cells, the osteocyte has been recognised as the orchestrator of bone remodelling,playing a key role in directing osteoblastic and osteoclastic activities. Conventional optical and electron microscopies havegreatly improved our understanding of the cell physiology mechanisms involved in different osteoarticularpathophysiological contexts, especially osteoporosis. More recently, imaging methods exploiting synchrotron radiation,such as X-ray tomography, ptychography, and deep ultraviolet and Fourier transform infrared spectroscopies, haverevealed new biochemical, chemical and 3D morphological information about the osteocyte lacuna, the surrounding matrixand the lacuna–canalicular network at spatial length scales spanning microns to tens of nanometres. Here, we reviewrecent results in osteocyte lacuna and lacuna–canalicular network characterisation by synchrotron radiation imaging inhuman and animal models, contributing to new insights in different physiologic and pathophysiological situations.