Structure changes of zebrafish midbrain vasculature during development.

<p>(A) Projected confocal images of a 3-dpf <i>Tg(kdrl:eGFP,HuC:gal4-uas-mCherry)</i> zebrafish larva showing the brain blood vasculature (green) and neural tissue (red, bottom). The dashed lines delineate the midbrain position. C, caudal; L, lateral; E, eye; F, forebrain; H, hindbrain; M, midbrain. Dorsal view, caudal is up. The same orientation is used for images and centerlines of whole-midbrain vasculature in all of the following figures. Scale, 100 µm. (B) 3-D reconstruction of the basal communicating artery (BCA, yellow), midbrain vasculature (white), and choroidal vascular plexus (CVP, blue) in the brain shown in (A). Red dots represent the branch points between vessel segments in the midbrain. (C–G) Developmental expansion and simplification of the midbrain vasculature. The data were obtained from eight larvae with each imaged at 2.0, 3.0, 4.0, and 7.5 dpf. (C) Representative midbrain vasculature centerlines of a larva at 2.0 (top), 4.0 (middle), and 7.5 dpf (bottom). Red, orange, yellow, green, cyan, and blue mark vessel segments with the 1^st–6^th Strahler order, respectively. The white lines indicate internal vessel loops, and the white dots represent branch points between the CVP and midbrain vessel segments. (D–G) Summary of developmental changes in the total vessel length (D), segment number (E), weighted average segment Strahler order (F), and internal loop number (G) of the midbrain vasculature. * <i>p</i><0.05; ** <i>p</i><0.01; *** <i>p</i><0.001 (paired Student's <i>t</i> test). Error bars, ± SEM.