Signaling through gp130-containing receptors on endothelial cells increases P-selectin–dependent thrombosis in flow-restricted veins. (A) Representative images of gp130 expression (red) in the IVC of tamoxifen-treated WT or gp130^flox/floxVECad-Cre-ER^T2 mice obtained with spinning-disk intravital microscopy. Fluoresbrite red microspheres coated with anti-gp130 mAb or isotype control mAb were injected IV into tamoxifen-treated WT or gp130^flox/floxVECad-Cre-ER^T2 mice 20 minutes before exposing the IVC. Top, IVC of tamoxifen-treated WT mouse injected with isotype control mAb-coated beads; middle, IVC of tamoxifen-treated WT mouse injected with anti-gp130 mAb-coated beads; bottom, IVC of tamoxifen-treated gp130^flox/floxVECad-Cre-ER^T2 mouse injected with anti-gp130 mAb-coated beads. The graph at right indicates quantification of the covered area of adherent microspheres with digital image-analysis software. The data represent the mean ± SEM from 5 mice. Scale bar, 10 μm. (B-C) Quantification of endothelial surface area covered with firmly adherent Ly6G⁺ neutrophils or M-CSFR⁺ monocytes, 3 hours after ligation of the IVC. (D-E) Kinetics of thrombus development (frequency) and thrombus size (area) in mice of the indicated genotype, measured by ultrasonography at the indicated times after ligation. (F) Thrombus weight in the indicated genotype 24 hours after ligation. Each symbol represents an individual thrombus. Horizontal red bars represent median values. (G-H) Number of Ly6G⁺ neutrophils or M-CSFR⁺ monocytes per thrombus 24 hours after ligation in the indicated genotype, as measured by flow cytometry. (I-J) Normalized thrombus weight per Ly6G⁺ neutrophil or M-CSFR⁺ monocyte. The data represent the mean ± SEM from 5 to 12 mice in each group. *P < .05; **P < .01.