Vascular changes evident in the hypoplastic thymic lobes improve following minoxidil administration. (A) Intact thymic lobes from E15–15.5 embryos (Tbx1^+/+;+/neo2 and Tbx1^neo2/neo2) were stained with antibodies specific for the endothelium (VE-cadherin [VE-Cad]) and vascular smooth muscle (SMA). Whole-mount imaging and stitching was used to recreate the entire lobe, revealing arterial bifurcations. (B) The images were expanded to reveal a specific bifurcation with the levels of VE-Cad within and surrounding the arteriole shown. The zoomed-in area is shown by the line connecting the region. This was a single slice, enabling the selection of a cross-sectional view. (C) E15–15.5 embryonic thymuses from the indicated carrier or drug-treated pregnant mice were processed for whole-mount imaging. Antibodies specific for VE-Cad (endothelium), SMA, and connexin 40 were used to compare the vasculature and morphology of the tissues. The composite image was created by stitching individual subsections of the image together. (D) The number of bifurcations per thymic lobe, SMA length, cross-section area, and ratio of SMA length to Cx40 staining intensity determined for control (Tbx1^+/+; n = 7), hypoplastic lobes (Tbx1^neo2/neo2; n = 6), and minoxidil treatment groups for wild-type (n = 6) and mutant (n = 8) shown. Statistical comparisons were performed with two-way ANOVA.