Opposite effects of VEGF and sNRP-1 on chloroma neovascularization.

(A) In vivo secretion of VEGF. Tumors from mice injected with encapsulated NMuMG/VEGF cells were harvested after 21 days and processed for histologic examination. Tissue sections were stained with anti–human VEGF antibodies and photographed under × 100 (left) and × 400 (right) original magnification. A cross-sectioned capsule and surrounding tumor tissue is shown. Some VEGF-positive stained cells can be seen within the capsule. (B) Tumor neovascularization. Tumors from NMuMG (control), NMuMG/VEGF (VEGF), and NMuMG/sNRP-1 (sNRP-1) groups, as indicated, were harvested and processed for histologic examination. Tumor sections were stained with H&E (top panels) and with anti–mouse CD31 antibodies (bottom panels) and photographed under × 400. (C) Microvessel density (MVD) was determined by counting 10 high-power fields (HPFs) from the CD31 stained sections in panel B. The numbers represent the MVD average, and standard deviations were calculated.