HDFs (C) were cultured in media containing increasing concentrations of r.h. TGF-β1 at 0, 0.1, 0.3, 1, 3 and 10 ng/ml for 24 h, before protein lysates or total RNAs were harvested. Western blot analysis of Smad7 was performed with protein lysates and semi-quantitatively analyzed with densitometry. β-actin served as loading control. Data is given as mean ± SEM of three independent blots. * 