Inhibition of neovascularization by peptides FSEN and FSEC in the Matrigel plug assay. (A) Blood vessels developed for 7 days in nude mice, injected with Matrigel plugs containing 50 ng/ml bFGF alone (positive control), PBS (negative control), and bFGF with 10 μM SPARC peptides FSEN, FSEC, or scrambled control peptides scFSEN and scFSEC. (B) For quantitative analysis of angiogenesis and blood vessel architecture, endothelial cells were visualized with green CD31 immunofluorescence, and pericytes were detected with red SMA antibody. Representative photographs at ×400 magnification are shown. (C) The relative quantity of endothelial cells and pericytes was estimated by calculating the area occupied by green and red fluorescence (in pixels). There were statistically significant decreases in the blood vessel area and quantity of pericytes in the Matrigel plugs containing SPARC peptides compared to the positive control with bFGF alone (single asterisk) and from the negative control (double asterisk).