EHCgp130^−/−mice overexpress CXCL1 in endothelial cells. (A) Frozen sections of cremaster muscle from WT and EHCgp130^−/− mice were stained with mAbs to CXCL1 (red) and CD31 (green). Fluorescent images were visualized with a confocal microscope. Yellow staining indicates overlapping distribution of CXCL1 and CD31 in the merged images. The bar represents 50 µm. The bar graph quantifies the relative fluorescence intensity for CXCL1. (B) Quantification of CXCL1 protein in cremaster muscle. (C) Quantification of CXCL1 protein in serum before or after intravenous injection of heparinase. (D) Quantification of mRNA for CXCL1 and CXCL2 in cremaster muscle. (E) Images of Fluoresbrite Red microspheres coated with anti-CXCL1 mAb or isotype control IgG (injected intravenously) adhering to endothelial cells in unstimulated or trauma-stimulated venules of cremaster muscle of each genotype. The bar represents 100 µm. The bar graph quantifies the relative fluorescence intensity of the adherent microspheres. The images in (A) and (E) are representative of 3 independent experiments. The data in the bar graphs represent the mean ± SEM from 15 to 20 venules from 4 to 5 mice in each group. The data in (B-D) represent the mean ± SEM from 5 mice in each group. *P < .05, **P < .01.