Angiogenesis and lymphangiogenesis induced by Ad-VEGF-DΔNΔC in skin.

Tissue sections were taken 3 weeks after injection of PBS, Ad-GFP, Ad-VEGF-DΔNΔC, or Ad-VEGF-A₁₆₅. (A) Serial sections were stained for VWF, and laminin and positive vessels per field were quantified. A 100% value was assigned to VWF-positive vessels, and percentages denote the proportion of vessels that were also laminin positive. Bars represent means ± SE for 3 separate tissue samples in each group. (B) Sections were stained for VEGFR-2 and VEGFR-3, and vessel areas were measured using a 10 × 10 graticule. All areas in 4 × 20-mm tissue samples were analyzed. Bars represent percentages of area covered by positively stained vessels ± SE. Note the predominant formation of VEGFR-2–positive vessels after Ad-VEGF-A₁₆₅ injection and VEGFR-3–positive vessels induced by Ad-VEGF-DΔNΔC. (C-G) Samples 3 weeks after injection of Ad-VEGF-DΔNΔC. Tissue sections stained for laminin (C), VEGFR-2 (G; higher magnification of the same area in D; ×20 objective), and VEGFR-3 (E, F) are shown. Blood vessels (bv) and lymphatic vessels (lv) are indicated. Lymphatic channels with single endothelial cell layer were not stained for laminin (C) or for VEGFR-2 (D), but they demonstrated significant expression of VEGFR-3 (F). Note the absence of VEGFR-3 staining of vessels filled with red blood cells (E). Panels C-F, ×50 objective.