Figure 6.

Representative photomicrographs of lung histopathology in groups B (vehicle + bleomycin) and C (N-acetylcysteine (NAC)+ bleomycin) at 3 days (a) and (b), respectively) and 15 days (c, d) and (e), respectively) following endotracheal bleomycin. Lung sections were stained with haematoxylin–eosin. NAC dose was of 300 mg kg⁻¹ per day given intraperitoneally. Normal lungs observed for group A (vehicle + vehicle) are not shown. Three days after intratracheal bleomycin, a marked peribronchial interstitial infiltration of inflammatory cells and alveolar oedema were patent in vehicle-treated animals (a). These pulmonary lesions were not improved by NAC (b). At 15 days postbleomycin, inflammation and fibrosis were present in vehicle-treated rats ((c,d)), but NAC ameliorated the pulmonary lesions (e). Panels (f) (group B) and (g) (group C) show lung sections stained with Masson-trichrome at 15 days postbleomycin. The presence of interstitial collagen was diminished by NAC. Original magnification of panels × 10 (except (d) × 20).