Fibrosis is significantly decreased in PDGF-C Tg;Smad3 KO mice. Liver tissue from WT, Smad3 KO, PTg, and PTg/KO mice was stained for collagen deposition using Picrosirius Red staining, and morphometric analysis was done as described in materials and methods (2–5 mo of age, n = 4–5). *P < 0.05; **P < 0.01.