COL3A1 and Hepatic fibrosis: Moreover, transcripts of key genes that regulate hepatic fibrosis, collagen 1A1 and 3A1 (Col1A1and Col3A1), α-smooth muscle actin (α-Sma), transforming growth factor-β1 (Tgf-β1), tissue inhibitor of metalloproteinases 1 (Timp-1), and platelet-derived growth factor receptor-β (Pdgfr-β) were all increased in HFrD-fed A/AHep mutant mice (Fig. 2g).