FIG. 4.
Moderate hypoxia (2% O2) enhances the growth and stability of preformed vessels. (A) Schematic of the experimental approach. Vessels were allowed to assemble for 6 days in 20% O2 before being transferred to 0.2%, 2%, or 20% O2 with no subsequent feedings after day 6. (B, F) Vessels grew significantly longer in hypoxia by day 12 versus day 6 (dotted line), with statistically greater length in 2% O2 relative to 0.2% and 20% O2. (C, G) Pericyte coverage decreased in all groups relative to day 6 values (dotted line), but was highest in 2% O2. (D, E, H) Proliferation (indicated by BrdU incorporation) decreased in all groups relative to day 6 values (dotted lines), but remained highest in the 2% O2 group. Scale bars = 500 μm (F), 100 μm (G, H). Significance indicated versus normoxia (20% O2) as *p < 0.05 or **p < 0.01. Color images available online at www.liebertpub.com/tea