Figure 3.

Fn matrix assembly is required for angiogenesis in vivo. (A) Type I collagen/fibrin composite gels polymerized in perforated transwell chambers were prepared. A Matrigel reservoir containing 200 ng of VEGF and 100 ng of HGF with either the Del29 control peptide or the FUD peptide was placed atop the matrix. (Top panels) The apparatus was placed atop the dropped CAM, and angiogenesis was allowed to proceed. After 3 d, the gels were harvested and vascular ingrowth was monitored by light microscopy following H&E staining (bar, 40 μm). (Bottom panels) In some experiments, FITC-Fn was supplemented in the matrices during the culture period, and Fn fibrillogenesis within the gels was monitored by confocal laser microscopy (bar, 50 μm). (B) After sectioning, lumina per 40× field were counted.