Effect of SDF-1 on in vivo differentiation of c-kit⁺ cells. (A) C-kit⁺ cells were obtained from mice ubiquitously expressing GFP protein. FACS analysis of GFP⁺/c-kit⁺ cells purified from these mice by MACS. (B-E) GFP⁺/c-kit⁺ cells were injected into adductor muscles at the time of femoral artery dissection. (B-C) Expression of GFP (green fluorescence) and α-actin (red fluorescence) in 2 consecutive sections. (D-E) Expression of GFP (green fluorescence) and VWF (red fluorescence) in 2 consecutive sections. The presence of GFP⁺ (arrows) and GFP^– (arrowheads) endothelial cells is shown. (F-J) Trichrome-Masson staining of MT plugs containing SDF-1 and/or c-kit⁺ cells. (F) Background angiogenesis in MT-only injected mice. (H) A relative increase in the number of small vessels by injecting MT-containing c-kit⁺ cells. (G,I) An enhanced number of blood vessels in MT–SDF-1 (G) and MT–SDF-1/c-kit⁺ cell injected mice. (J) Quantification of the total blood vessel density (expressed as blood vessels/mm²) in MT plugs in all experimental conditions. *P < .05; n = 4, for each mice group. Error bars indicate standard errors.