Influence of Morphine on Pericyte-Endothelial Interaction: Implications for Antiangiogenic Therapy
Figure 4
Morphine stimulates vessel-associated Desmin expression in mouse tumors. C3TAG mice were treated with morphine or PBS as described in Figure 3 and the methods. (a) Upper row shows tumor sections stained with anti-CD31 for vasculature (green) and desmin (red). Morphine-treated tumors show strong desmin (red) staining associated with tumor endothelium (green) as well as independent of vasculature (magenta arrow). Orange staining suggests an overlap between red and green staining for desmin and vasculature, respectively. Lower row shows strong costaining of α-smooth muscle actin (SMA, red) with CD31 (green), in both PBS and morphine-treated mice tumors. Magnification ×150. Each image represents 5 different tumors from 5 different mice per treatment. (b) Ratios of desmin to CD31- and α-SMA to CD31-immunoreactive pixels are shown. A significant difference is observed in desmin/CD31 ratio between morphine and PBS treatment but not in α-SMA/CD31 ratio. Each bar represents mean ± SEM of immunoreactive pixels from five tumors (3 different sections of each tumor) obtained from 5 different mice per treatment. (c) Enlargement of area shown with yellow arrow in (a) for CD31/desmin staining in morphine-treated mice. It shows colocalization of desmin staining in the sprouting endothelial cell and in the tip cells.
