Figure 1.

Impaired angiogenesis in Vegf^ΔTie2-Cre embryos. A, B, Isolectin B4⁺ periventricular vessel gradient (white arrows) in E13 Vegf^fl/fl (A) and Vegf^ΔTie2-Cre (B) telencephalon. C, D, Fewer isolectin B4⁺ vessels in E17 Vegf^ΔTie2-Cre pallium (D, red arrows) compared with Vegf ^fl/fl pallium (C, white arrows). E, F, Fewer laminin⁺ vessels in E17 Vegf^ΔTie2-Cre pallium (F, red arrows) compared with Vegf^fl/fl pallium (E, black arrows). G, H, Fewer PECAM-1⁺ endothelial cells in E17 Vegf^ΔTie2-Cre pallium (H, red arrows) compared with Vegf^fl/fl pallium (G, white arrows). I, J, Double labeling of endothelial cells with isolectin B4 and BrdU (white arrows point to colabel in yellow) shows no differences in endothelial cell proliferation in E13 Vegf^fl/fl and Vegf^ΔTie2-Cre telencephalon. K, Endothelial cells proliferate in neurogenic and postmitotic regions of E17 Vegf^fl/fl telencephalon (white arrows point to coexpressing cell nuclei that appear in yellow). L, Endothelial cells proliferate only in neurogenic regions (white arrows), and there is lack of BrdU-isolectin B4 colabel in postmitotic regions (red arrows) of Vegf^ΔTie2-Cre telencephalon. M, Endothelial cell BrdU labeling index was comparable in E13 Vegf^fl/fl and Vegf^ΔTie2-Cre telencephalon (n = 8, mean ± SD, p > 0.05) and significantly decreased in E17 Vegf^ΔTie2-Cre telencephalon compared with Vegf^fl/fl telencephalon (n = 8, mean ± SD, *p < 0.05). N, Dilated and stretched vessels were detected in the E17 Vegf^ΔTie2-Cre telencephalon. Scale bars: A (applies to B–D, I–L), 100 μm; E (applies to F), 75 μm; G (applies to H), 50 μm; N, 25 μm. n = 8.