Figure 2. In vivo imaging of the same mouse over time demonstrates that SKL cells tend to engraft and proliferate near the endosteal region.

(a) Mosaic images of time-lapse in vivo imaging of a tibia window. 3×10⁴ GFP⁺ SKL cells were injected at Day 0 and in vivo colony formation from SKL cells was monitored in the same animal over time (n=6). Scale bar=500μm (b) Higher magnification of single GFP⁺ cells engrafted on the endosteal surface developing into a colony (the boxed region at Day 4). Injected SKL cells homed to the marrow and developed into a colony over 4 days (Red arrowheads, the same area marked at the mosaic images). However, not every cell homed to the endosteal surface formed colonies (white arrows). Scale bar=200μm.