Density of monocyte-derived cells and expression of interleukin-6 (IL-6). (A) Representative fluorescent micrographs from the empty scaffold, multipotent stromal cell (MSC), and MSC/endothelial cell (MSC/EC) constructs, showing mouse-specific CD11b- and IL-6-positive multinucleated cells after 3 weeks of implantation in vivo (10× magnification, scale bar = 100 μm). Five sections from each mouse and five images for each section were used for the image quantification. (B) The number of cells positive for CD11b and IL-6 was lower in the MSC/EC group (*P <0.05, n = 6). (C) Relative protein expression of IL-6 in MSC and MSC/EC constructs. (D) Giant-cell co-staining with CD11b and IL-6 at 63× magnification. Scale bar = 20 μm. Overall larger giant cells were observed in the MSC/EC group. S, scaffold.