Nigella sativa attenuates bleomycin-induced pulmonary fibrosis in rats by inhibition of inflammation, fibrosis, and inducible nitric oxide synthase

Abstract

The present study investigated the anti-oxidant, anti-inflammatory and anti-fibrotic potential of Nigella sativa (NS) against bleomycin (BLC)-induced lung injury and fibrosis, an experimental animal model. A total of 18 male Sprague-Dawley rats were divided into three groups: Control, BLC, BLC+ NS ; each group consist of 6 animals. Pulmonary fibrosis was induced by a single intratracheal instillation of 2.5 mg/kg BLC. BLC+ NS group rats were intragastric administered daily 400 mg/kg of NS from day 1 to 28. At the end of the study, lung tissues were removed for histopathological and immunohistochemical investigation. Lung tissues were stained with hematoxylin and eosin and Masson’s Trichrome for histological evaluation. Moreover, the inducible nitric oxide synthase (iNOS) expression in the lung tissues was determined by immunohistochemical staining. BLC-induced histological changes including lung inflammation and lung fibrosis were significantly detected compared to the control group. NS treatment significantly ameliorated the BLC mediated histological changes and reduced the inflammatory cell infiltrate in lung tissues. NS significantly blocked collagen accumulations with parallel reduction in the fibrosis score. In addition, NS also markedly decreased the positive staining of iNOS in lung tissues. Our study provides evidence that NS significantly ameliorated BLM-induced pulmonary fibrosis in rats via the inhibition of inflammation score, fibrosis score, and iNOS expression. Therefore, NS may be a potential therapeutic reagent for the treatment of lung fibrosis.