G-CSF/SCF treatment increases angiogenesis and many of the new endothelial cells are of donor BM origin. Vascular density is demonstrated in untreated (A) and G-CSF/SCF–treated (B) mice after stroke (→). The insets are high-magnification representative images of coronal sections from similar rostro-caudal levels of the brains. (C) Columnar graph showing the percentage of the surface area occupied by vessels based on alkaline phosphatase staining in the sections of the saline-treated versus G-CSF/SCF–treated mice in both hemispheres. Vascular density is demonstrated in untreated (D) and G-CSF/SCF–treated (E) mice after stroke. The vascular endothelial cells are immunostained for CD31 (red fluorescence due to Alexa-594), and the GFP cells are immunostained in green following signal amplification using FITC-tyramide. For panels A,B,D,E: objective, 10×; numeric aperture, 0.3, Plan Fluo. Note the increased density of vessels as well as more green vascular structures in the G-CSF/SCF–treated brain. (F) The columnar graph demonstrates the percentage of GFP⁺ (ie, BM-derived; green) cell surfaces compared with all (red) endothelial (CD31-stained) surfaces in the saline-treated versus G-CS/SCF–treated mice brains in both hemispheres (n = 4). Values are means plus SEM. **P < .01. CC indicates corpus callosum; v, lateral ventricle.