bFGF is involved in hypoxic induction of cords in HUVECs. (A) HUVECs seeded on Matrigel in GF^– medium were incubated under hypoxic conditions for 16 hours in the presence or absence of specific neutralizing antibodies for IGF-1, VEGF, bFGF, and PDGF-BB (100 ng/mL). (B) HUVECs were treated with 20 ng/mL IGF-1, VEGF, bFGF, or PDGF-BB, in the presence or absence of the specific neutralizing antibodies (100 ng/mL) for 16 hours, and cord formation was examined. Results are representative of 4 independent experiments.