Reactive nitrogen species induce tissue inflammation and nitrate tyrosine residues of various kinds of proteins. Recent studies have established that the free amino acid form of 3-nitrotyrosine induces cytotoxity and growth inhibition and alters the cellular function in cultured cells. The aim of this study was to evaluate whether 3-nitrotyrosine could affect tissue remodelling in fibroblasts. To accomplish this, human fetal lung fibroblasts (HFL-1) were used to assess the fibroblast-mediated contraction of floating gels and chemotaxis towards fibronectin. In addition, the ability of fibroblasts to release fibronectin, transforming growth factor (TGF)-beta1, fibronectin and vascular endothelial growth factor (VEGF) was assessed. 3-Nitrotyrosine significantly inhibited gel contraction (p<0.01) compared with control and this inhibition was abolished by nitric oxide synthase (NOS) inhibitor. 3-Nitrotyrosine did not affect TGF-beta1 and VEGF but significantly decreased fibronectin release (p<0.01) into the media. 3-Nitrotyrosine significantly inhibited chemotaxis towards fibronectin through suppression of alpha(5)beta(1) integrin expression (p<0.01). NOS inhibitor also reversed 3-nitrotyrosine-inhibited chemotaxis (p<0.01). Finally, 3-nitrotyrosine enhanced the expression of the inducible type of NOS (p<0.01) and nitric oxide release (p<0.01) through nuclear factor-kappaB activation. These results suggest that the free amino acid form of 3-nitrotyrosine can affect the tissue repair process by modulating nitric oxide production.