Role of HO-1 during in vivo angiogenesis. (A) Quantitative evaluation of neovessels infiltrating Matrigel after injection of aFGF (50 ng/mL), VEGF (40 ng/mL), or vehicle alone in the absence or presence of SnPP (20 μM). The results are expressed as percentage ± SE of the vessel area to the total Matrigel area. (B) Effect of SnPP (20 μM) and ZnPP (20 μM) on angiogenesis induced by VEGF (40 ng/mL). (C) Quantitative evaluation of inflammatory cells infiltrating Matrigel that were counted in sections stained with hematoxylin and eosin. The results are expressed as the mean ± SE of cells/field (× 400). Six mice were used per condition in each experiment.