Fig. 3.

Anti-Bv8 treatment reduces VSA and neutrophil infiltration in hyperplastic and angiogenic lesions in prevention but not in intervention trials. RIP-Tag mice were treated with control, anti-Bv8, or anti-VEGF mAbs in prevention or intervention trials, as described. Evaluations were performed at the end of such periods. Sections (6 μm) were cut from frozen tumors and stained with anti-CD31 (shown in red) and anti-Gr1 (shown in green) antibodies as described. (A) VSA was assessed on the basis of the percentage of CD31+ areas relative to the entire lesion in each treatment group. Bars represent the mean VSA ± SEM. Data represent VSA from at least three mice per treatment. (B) Representative images of hyperplastic, angiogenic, and tumor lesions from prevention trials. RIP-Tag mice were treated with control, anti-Bv8, or anti-VEGF mAbs for 5 weeks. Tumor sections were stained with anti-CD31 (shown in red) to label blood vessels and anti-Gr1 (shown in green) to label neutrophils. Nuclear counterstaining with DAPI is shown in blue. Arrows point to Gr1+ cells in hyperplastic and angiogenic lesions. Dotted lines show the boundaries between hyperplastic islets and the surrounding exocrine tissue; angiogenic islet and tumor photomicrographs are focused within the core of the lesion. Anti-Bv8 treatment reduces neutrophil infiltration in the exocrine pancreas. (C) RIP-Tag mice were treated in an intervention trial with control, anti-Bv8, or anti-VEGF mAb, and VSA was measured in tumor sections (n = 3) as described. (D) Images are representative of hyperplastic, angiogenic, and tumor lesions at the end of intervention trials. Vascular structures and neutrophils are shown in red and green, respectively. DAPI-counterstained nuclei are shown in blue. * indicates significant difference (P ≤ 0.05) when comparision with the control mAb-treated groups. (Magnification: B and D, ×20.)