Introduction: Pulmonary fibrosis is a progressive, life-threatening disorder characterized by alveolar disruption, chronic inflammation, oxidative stress, and excessive collagen deposition. This study investigated the protective and antifibrotic effects of an aqueous-alcoholic extract of Scrophularia striata in a bleomycin-induced rat model.
Methods: Fifty male Wistar rats were randomized into five groups: control, bleomycin (7.5 U/kg intratracheally on day 1), and three bleomycin plus extract groups receiving S. striata (50, 100, or 200 mg/kg orally from days 7 to 28). After 28 days, animals were euthanized, and the pulmonary index, lung hydroxyproline, malondialdehyde (MDA), reduced glutathione (GSH), antioxidant enzyme activities (SOD, CAT, and GPx), nitric oxide (NO), and TNF-α levels were evaluated. Histopathology was assessed by H&E and Masson ’s trichrome staining and scored using the Ashcroft scale.
Results: Bleomycin produced significant pulmonary injury, with increases in the pulmonary index, hydroxyproline, MDA, NO, and TNF-α levels and marked reductions in GSH levels and antioxidant enzyme activities (P < 0.001). S. striata extract ameliorated these alterations in a dose-dependent manner; the 200 mg/kg dose produced the greatest protective effect (P < 0.05 vs. bleomycin). Histological analysis confirmed reduced inflammatory infiltration, thinner alveolar walls, and decreased collagen deposition, with lower Ashcroft scores in treated groups.
Conclusion: The aqueous-alcoholic extract of S. striata exerts significant protective and antifibrotic effects in bleomycin-induced pulmonary fibrosis, likely through attenuation of oxidative stress, restoration of antioxidant defenses, and suppression of local inflammation. These findings support further mechanistic studies and preclinical evaluation of S. striata as a potential adjunct therapy for pulmonary fibrosis.