Figure 5

The MAC proangiogenic paracrine effect is dependent on secreted IL-8, but independent of extracellular VEGF. Using a PKH kit, we prelabeled RMECs in green and MACs in red before culturing them in the 3D Matrigel Tubulogenesis Assay. Representative images are shown of RMECs alone forming tubes (A); cocultures of RMECs and MACs (B); addition of IL-8 neutralizing antibody to a coculture system (C); and addition of neutralizing VEGF antibody to cocultures (D). Scale bars for A–D: 250 µm. (E) Quantification of tube areas in response to treatments. Anti-IL-8 significantly decreased RMEC tube formation; however, neutralizing VEGF had no significant effect on RMEC tubulo-genesis. Data are expressed as mean ± SEM. **P < 0.01 versus control; *P < 0.05 versus control; ns: not significant.