Xenogeneic transplantation of mesenchymal stem cells. (A to E) Photomicrographs showing frontal sections, 10 μm thick, of the whole knee joint stained with safranin O. (B' to E') Fluorescent microscopy for in vivo tracing of injected mesenchymal stem cells (MSCs). Bar = 500 μm (A), 200 μm (B to E, B' to E').
Sato et al. Arthritis Research & Therapy 2012 14:R31 doi:10.1186/ar3735