Fig 2: Metformin inhibits fibroblast activation and glycolytic capacity. Primary human fibroblasts were treated with PBS (control), TGF-β (10 ​ng/ml), or TGF-β (10 ​ng/ml) ​+ ​metformin (2 ​mM) for 48 ​h. a-b Immunofluorescent staining of α-SMA and FN1. c-d The results of quantitative analysis showed a significant decrease in α-SMA and FN1 expression in fibroblasts treated with metformin (n ​= ​3). e The effects of metformin on the protein synthesis of α-SMA, FN1, GLUT1, HK2, PFKP, PKM2, and LDHA. f Statistical analysis of protein expression levels shown in (e) (n ​= ​3). Protein abundance was normalized to β-actin and expressed as relative value to the level in control cells that was designated 1. g mRNA levels of α-SMA, FN1, GLUT1, HK2, PFKP, PKM, and LDHA were quantified by qRT-PCR (n ​= ​3). Data was normalized to β-actin and expressed as value relative to the level in control cells that was designated 1. The data are shown as mean ​± ​SEM. ∗comparison between control and TGF-β treated cells, #comparison between TGF-β and TGF-β ​+ ​metformin treated cells. ∗P<0.05, ∗∗P<0.01, ∗∗∗P<0.001, ∗∗∗∗P<0.0001 by one-way ANOVA followed by Tukey–Kramer test. Scale bars: 50 ​μm.