Attenuation by oral N-acetylcysteine of bleomycin-induced lung injury in rats

Antioxidant therapy may be useful in diseases with impaired oxidant-antioxi dant balance such as pulmonary fibrosis, This study examines the effect of N-acetyleysteine (NAC) on bleomycin-induced lung fibrosis in rats. NAC (3 mmol.kg(-1);oral) was given daily from I week prior to a single intr atracheal instillation of bleomycin (2.5 U.kg(-1)) or saline, until 14 days postinstillation, NAC partially decreased the augmented collagen deposition in bleomycin-expo sed rats (hydroxyproline content was 4,354 +/- 386 and 3,416 +/- 326 mug.lu ng(-1) in vehicle-treated and NAG-treated rats, respectively; p <0.05), The histological assessment using a semiquantitative score showed less collage n deposition and inflammatory cells in NAC-treated rats compared to those r eceiving bleomycin alone. NAC failed to inhibit the bleomycin-induced incre ases in lung wet weight and in cell counts and protein levels of bronchoalv eolar lavage fluid, but significantly increased total glutathione and tauri ne levels in bronchoalveolar lavage fluid. These results indicate that oral N-acetylcysteine improves the pulmonary an tioxidant protection and may be useful in reducing lung damage produced by bleomycin.