The antiangiogenic activity of the various rPEDF forms on bFGF-induced neovascularization in the in vivo Matrigel plug assay. A) CD-1 nude mice were subcutaneously injected with 0.5 mL Matrigel containing rPEDF, plPEDF, S24, 114E mutant, and S227E mutant (all at 20 nM) in the presence or absence of bFGF (300 ng/mL). Control plugs were combined with PEDF (20 nM) or bFGF (300 ng/mL) only. After 7 days, mice were killed and Matrigel plugs were excised, fixed in 4% formaldehyde, embedded in paraffin, sectioned, and stained. Representative fields of H&E staining of thin sections from Matrigel plugs of each arm of the experiments were taken using light microscope (Nikon E600 connected to DxM 1200 F camera) (× 40 magnification). (B) Angiogenesis was measured by counting the number of blood vessels/field for 3 different cross-sectional areas of each Matrigel plug. Student t test was used to analyze statistical significance of the differences between plugs treated with bFGF and plugs treated with the combination of bFGF and the various PEDF forms (^*P < .01; ^**P < .05; n = 3).