Vardenafil inhibited TGF-β1-mediated, matrix-associated mRNA levels in lung fibroblasts. The effect of the respective mRNA transcripts in human IMR-90 fibroblasts stimulated with TGF-β1 after 24 h in the presence of the indicated vardenafil concentrations are shown. (A) Collagen type I, alpha 1 (COL1A1), (B) fibronectin, and (C) thrombospondin (TSP-1) relative mRNA expression in IMR-90 lung fibroblasts. Data are from six experimental runs and are expressed as means ± SEM. * p < 0.05, comparing the tested condition to the control maximal stimulation in the presence TGF-β1 but in the absence of vardenafil.