Fig. 4.

Disruption of angioblast and endothelial cell cytoskeletons by hyperoxia. A–F: Photomicrographs were taken of angioblasts (A–C) and endothelial cells (D–F) exposed to 0 (A,D), 3 (B,E), and 5 (C,F) days of hyperoxia. These cells were then labeled with Phalloidin (green), and angioblasts were also labeled with anti-smooth muscle actin (red, SMA). The cells were counterstained with 4′,6-diamidine-2-phenylidole-dihydrochloride (DAPI, blue). G: The percentage of cells with an intact cytoskeleton, as shown in upper panels, was determined. The SEM is indicated by bars. *P < 0.05 to normoxic angioblasts, and **P < 0.05 when compared with either normoxic/hyperoxic quiescent or normoxic dividing/migrating endothelial cells. All angioblast counts were significantly less (P < 0.05) than endothelial counts after the first day.