RNase treatment and VEGFR2 blockade interfere with VWF release during arteriogenesis. Laser Doppler perfusion measurements (A) along with corresponding flux images (B) of DMSO (solvent)-treated mice compared with semaxanib-treated mice. The perfusion recovery was calculated by the occluded/sham (right to left) ratio before the surgical procedure, immediately after the surgical procedure, and 3 days and 7 days after ligation. Representative flux images of the Laser Doppler perfusion measurements are shown for day 3 and day 7. The scatter plot shows the inner luminal diameter of mice treated with DMSO or semaxanib 7 days after FAL (C) along with representative Giemsa stains of evaluated tissue samples (D). Scale bars, 20 µm. (E) The scatter plot shows the amount of luminal VWF (as calculated by quantifying the mean green fluorescence intensity per luminal area) in mice treated with saline, DMSO, RNase A, semaxanib, or DC101 (antibody blocking VEGFR2) 2 hours after FAL. (F) Representative immunohistological stains of evaluated collateral arteries. ECs of growing collaterals are strongly decorated with VWF on their luminal surface (green dots; top and middle left panels); this is not visible in the other panels (saline sham, RNase A occ, semaxanib occ, or DC101 occ). Scale bars, 10 µm. Insets show magnifications of collateral arteries in boxes. Data are mean ± SEM. n = 6 per group (A-B), n > 10 per group (C-D), n = 3 per group (E-F). The dashed horizontal line in the scatter plots indicates the mean sham value. *P < .05, 2-way ANOVA with the Bonferroni multiple-comparison test (A), unpaired Student t test (C), 1-way ANOVA with the Bonferroni multiple-comparison test (E).