Cells injected in Matrigel are responsible for formation of new blood vessels.

<p>(A) Representative micrographs of GFP-positive endothelial cells. The presence of GFP was detected using anti-GFP antibody followed by biotinylated horse anti-rabbit secondary antibody, visualized using the DAB substrate system. Arrows highlight positive endothelial cell staining in intact vessels. (B) Micrographs depicting negative staining in rat sections using an isotype control antibody. Arrows indicate endothelial cells that do not display staining using the control antibody. All micrographs were taken using a Nikon 80i upright microscope fitted with a 60X objective.