Fig. 1

In vivo monitoring of the angiogenic process during fin regeneration.

Panel "a" displays the reference image of caudal fin (just before amputation) taken with both normal bright and fluorescent reflected light. The vessels appear green (eGFP in Tie-2 positive endothelial cells). Panel "a' " displays a representative image of the regenerated caudal fin at 7 dpa (days post amputation). The dotted line indicates the amputation level. Panel "b" displays the vascular regeneration process at higher resolution at example of one fin ray. Starting from 10 dpa the vasculature starts to resemble the reference vascular pattern before amputation (Ref). The red-green image in panel "c" demonstrates the outgrowth of the vasculature between 3 dpa (red) and 5dpa (green): one can easily follow the formation of every single vessel segment in dynamics. Arteries situated in the central part (core) of the ray (one per ray) can be clearly distinguished from the veins (2 per ray) situated aside from the ray core (see markings in c). Panel "d": high resolution in vivo time lapse images demonstrating the fate of single capillary sprouts within 4 hours. Left image shows the vessels at 48 hours post amputation (hpa), already one hour later opposing sprouting tips are approaching each other. By 50 hpa, the opposing vessel walls seem to be already attached. At 51 hpa the new vascular segment is formed and already perfused. Endothelial cell nuclei are fluorescing intensive green.