Figure 5. After 4 weeks of parabiosis circulatory OCP do not engraft in the primary and secondary spongiosa.

Images of sections from the femoral bone of a wild type mouse and TRAP tdTomato mouse that were parabiosed for 4 weeks. In the wild type mouse arrows indicate cells that are TRAP positive by enzyme histochemistry but are negative for tdTomato. In the TRAP tdTomato mouse arrows indicate cells that are double positive for the tdTomato reporter and TRAP as stained by enzyme histochemistry. The sections were also stained for DAPI to identify nuclei and then scanned to visualize multinuclear tdTomato positive cells. After imaging under fluorescent light, sections were stained for TRAP by enzyme histochemistry and visualized under conventional light. Two images for each slide were overlaid using Adobe Photoshop CS6 (version 6.0, Adobe Systems Inc., San Jose, CA) and analyzed. Experiments were repeated eight times with similar results and representative samples are shown. Images are taken under 10x magnification, scale bar 500 μm.