Inhibition of VEGF signaling prevented tPA-mediated ischemic tissue recovery. (A-B) C57BL/6 mice were treated with tPA and coinjected with anti–VEGF-A or control monoclonal antibodies. (A) Ischemic recovery was quantified by laser Doppler (n = 3 per group). Asterisks indicate a significant difference between tPA-treated mice coinjected with IgG or anti–VEGF-A antibody. (B) Capillary density was quantified 15 days after ligation (n = 3 per group). HL ischemic mice treated with or without tPA were coinjected intraperitoneally with neutralizing doses of VEGFR-1 (C), VEGFR-2 (D), a combination of VEGFR-1 and VEGFR-2 (E), or IgG antibodies at 2-day intervals, starting from day 0, and functional perfusion measurements of the collateral region were performed in each group with the use of a laser scan (n = 3; *P < .05,**P < .001). (F) Quantification of the capillary density in tissue sections taken 15 days after artery ligation by CD31 staining of sections from HL-induced mice treated with or without tPA (n = 3; *P < .05; **P < .001 versus vehicle). (G-I) Blood cell counts were determined at the indicated time points. (G) WBC, (H) neutrophil, and (I) monocyte counts (*P < .05 comparison of the tPA plus IgG-treated HL group with the BSA-PBS plus IgG-treated group; †P < .05 comparison of the tPA plus IgG-treated HL group with the tPA plus anti–VEGF-A group; #P < .05 comparison of the tPA plus IgG-treated HL group with the tPA plus anti–VEGFR-1 group). Error bars represent SEM. (J) HL-induced C57BL/6 mice treated with tPA or BSA-PBS and antibodies against CD11b were cotreated with antibodies against VEGFR-1 or VEGFR-2. Capillary density was evaluated (n = 3 per group). If not otherwise indicated, a single asterisk (P < .05) and double asterisk (P < .001) indicate a significant difference between groups. Values represent the mean ± SEM.