Figure 4.

Loss of Twist1 decreases vascular sprouting in aortic ring and choroid explants ex vivo. (A) Fragments of aorta were dissected from adult Tie2-Twist1^cKO mice and littermate Twist1^flox/flox control mice and cultured as explants. Vascular sprouting areas were quantified, with aortic ring explants from Tie2-Twist1^cKO mice showing significantly decreased sprouting areas compared with those of Twist1^flox/flox littermate controls. Vascular sprouting areas are expressed as relative units normalized against the area of Tie2-Twist1^cKO rings at day 3 (***P ≤ 0.001, n = 5–6/group, scale bar: 1 mm). (B) Peripheral choroid/sclera fragments were obtained from adult Tie2-Twist1^cKO mice and littermate Twist1^flox/flox control mice and cultured as explants. Vascular sprouting areas in choroid explants from Tie2-Twist1^cKO mice show significantly decreased levels compared with those of Twist1^flox/flox littermate controls at day 7 (*P ≤ 0.05, n = 10–11/group, scale bars: 500 μm).