Calvarial (skull) osteocytes, murine, THG and SHG

Calvarial osteocytes (coloured white) encased in bone collagen matrix (coloured purple) from a mouse skull. Osteocytes are star-shaped cells that have dendritic processes or finger-like projections which extend out from the cell. They are found in fully formed bone and sit in a chamber or empty space called a lacuna. They play a key role in regulating bone remodelling (formation of new bone and removal or resorption of bone from the skeleton). This image was acquired by label-free third harmonic generation (THG) and second harmonic generation (SHG) microscopy, which is a type of two-photon microscopy used to visualise naturally occurring non-fluorescent signals from biological samples. THG was used to visualise the osteocytes and SHG to reveal the collagen of the bone matrix. The two signals were then overlaid to create this image. Width of image is 460 micrometres.