Figure 2: SMAD7 overexpression decreases production of hydroxyproline in fibroblasts derived from human Peyronie's disease plaque. Fibroblasts were transfected with an empty PEI25k/pCMV5 vector or a PEI25k/ pCMV5-Smad7 polyplex (pSmad7) for 48 h and were then treated with TGF-β1 (10 ng ml−1) for 24 h. Each bar depicts the mean values (± s.d.) from four experiments per group. ***P < 0.001 by ANOVA. PEI: poly (ethyleneimine); TGF-β1: transforming growth factor-β1; SMAD7: decapentaplegic homolog 7.