Effect of Sal B on vascular endothelial growth factor (VEGF). Immunohistochemistry for VEGF in epidural scar tissues treated with Sal B (a), Vehicle (b) or nothing (c). As shown in statistical analysis (d), the density of VEGF in the Sal B group (a) was less than the other 2 groups. *P < 0.05 vs the Vehicle and the Sham group. The density of VEGF in the Vehicle group was similar to that of the Sham group. The magnification was 400 ×.