Figure 6. Inhibitory effects of R667 on TGF-β1-induced fibronectin and type I collagen release by HTFs. Cells were cultured in collagen gels with or without transforming growth factor-β1 (TGF-β1; 1 ng/ml) and in the presence of various concentrations of R667 for 3 days, after which the culture supernatants were assayed for (A) fibronectin and the (B) C peptide of procollagen type I. Data are means ± standard deviation (SD) from three independent experiments. *p<0.01 versus the corresponding value for cells cultured without TGF-β1; †p<0.05 versus the corresponding value for cells cultured with TGF-β1 alone (the Tukey-Kramer test).