Exogenous IL-6, GM-CSF, and IL-8 promote HUVEC tube formation. (A) Quantification of Matrigel tube formation assay after 24 hours in the presence of human recombinant IL-6 (10 ng/mL). The results are expressed as mean ± SD, ^##P < .01 versus mock, **P < .01 versus mock + IL-6. (B) Representative examples of each culture condition are shown as a low-power image (magnification, ×10). (C) Quantification of Matrigel tube formation assay after 24 hours in the presence of increasing concentrations of GM-CSF. The results are expressed as mean ± SD, ^###P < .001 versus mock, ***P < .001 versus mock + GM-CSF (30 ng/mL). (D) Representative examples of each culture condition are shown as a low-power image (magnification, ×10). (E) Quantification of Matrigel tube formation assay after 24 hours in the presence of increasing concentrations of IL-8/CXCL8. The results are expressed as mean ± SD, ^##P < .01 versus mock, **P < .01 versus mock + IL-8/CXCL8. (F) Representative examples of each culture condition are shown as a low-power image (magnification, ×10).