Neutralization of the CXCL12 chemokine gradient in VEGF-A pretreated mice. (A-B) Mice were pretreated with VEGF-A (VA; 100 µg/kg mouse IP) or vehicle (dash) once daily on 4 consecutive days. Twenty-four hours after the last injection, mice were administered AMD3100, and 1 hour later, mice were sacrificed. Femoral bone marrow and peripheral blood were collected for quantification of CXCL12 in BM supernatant (A) and PB plasma (B), respectively (n = 6-15 mice per group). CXCL12 levels are shown as picograms per milliliter. (C) Mice were pretreated with VEGF-A or vehicle (dash) once daily on 4 consecutive days. Twenty-four hours after the last injection, mice were administered AMD3100 or vehicle (dash) in the presence or absence of C4P, and 1 hour later, blood was collected for analysis of circulating CFU-Fs (n = 6-10 mice per group). CFU-Fs are shown as colonies per milliter of blood. Data from at least 2 independent experiments are represented as mean ± SEM. *P < .05; **P < .01; ***P < .001 (one-way ANOVA with Bonferroni test). VA, VEGF-A.