Adoptive transfer of Gr-1⁺ cells from PAI-1 inhibitor-treated mice improves neoangiogenesis. (A-F) Muscle-derived Gr-1⁺ cells isolated from HL-ischemia–induced-C57BL/6 donors treated with/without PAI-1 inhibitor were transplanted into HL-ischemia–induced recipients for 3 days (n = 6/group). (A) Experimental scheme of the muscle-derived Gr-1⁺ cell transplantation assay. (B) Blood flow was determined after transplantation of PAI-1 inhibitor-mobilized versus vehicle-mobilized (mob.) Gr-1⁺ cells in HL-ischemic C57BL/6 recipients. (C) VWF immunostaining of lower limb ischemic tissue of mice receiving vehicle- or PAI-1 inhibitor-mobilized cell transplantations. Arrows indicate capillaries. Nuclei were counterstained with DAPI (blue staining). Scale bars indicate 200 mm. (D) Capillary density was evaluated per high-power field (HPF). (E) Immunofluorescent staining of Gr-1 and VEGF-A was performed on sections derived from vehicle or PAI-1 inhibitor-mobilized Gr-1 cell-transplanted mice. The arrows indicate transplanted Gr-1⁺ cells costained with VEGF-A in ischemic tissues. Nuclei were counterstained with DAPI (blue). (F) Quantification of Gr-1⁺ VEGF-1⁺ cells under a HPF. Data represent means ± SEM. *P < .05.