Fig. 10. In vitro angiogenesis assay using primary vascular endothelial cells isolated from the Sox17^+/--Sox18^-/- livers at P7, showing defective formation of the vascular-like structures on Matrigel. (A,B) Diff-Quik staining of the vascular endothelail cells cultured for 6 hours on Matrigel. PECAM1-positive endothelial cells were prepared from Sox18^-/- (left) livers and mild (middle) and severe (right) Sox17^+/--Sox18^-/- livers at P7. (B) Higher magnified image of the panel above in A. (C) Quantitative analyses showing the number of aggregated nodes per area (left), the branch number per node (middle), and vessel length per area (right) in the 6-hour cultures of the liver vascular endothelial cells isolated from Sox18^-/- (open bar), mild Sox17^+/--Sox18^-/- (gray bar) and severe Sox17^+/--Sox18^-/- (solid bar) groups (^**P<0.01; n=8 in Sox18^-/- and mild Sox17^+/--Sox18^-/- groups; n=4 in severe Sox17^+/--Sox18^-/- group). Bars, 100 µm.