Figure 2

Platelet depletion reduces tumor blood vessel density, pericyte coverage and perfusion. (A) Representative images of immunostaining of tumor sections for PECAM-1 (green) and α-SMA (red). Scale bar, 50 μm. Quantitative assessment of PECAM-1-positive blood vessels (B) and α-SMA /PECAM-1-positive cells (C) in B16/F10 tumors from platelet (PLT)-depleted and control mice. The results were represented as the mean percentage of area ± SME (n = 6). (D) Tumor blood vessel perfusion assay using FITC-dextran in vivo. Following 2 weeks of treatment with GPI or control antibody, tumor-bearing mice were injected (iv) with 0.2 ml FITC-dextran (25 mg/ml) for 20 min. Tumors and whole blood were collected, processed, and centrifuged. Fluorescence was measured in the supernatants from tumor tissue and whole body plasma. The ratio of tumor to plasma fluorescence reflects the extent of tumor perfusion. The results are expressed as the mean ± SEM. *p < 0.05. (n = 6 for each group).