Original article Nigella sativa, a traditional Tunisian herbal medicine, attenuates bleomycin-induced pulmonary fibrosis in a rat model Anouar Abidi a, *, Alexandre Robbe b , Nadia Kourda c , Saloua Ben Khamsa a , Alexandre Legrand b a Laboratory of Physiology, Faculty of Medicine of Tunis, University of Tunis El Manar, La Rabta, Tunis 1007, Tunisia b Laboratory of Physiology and Pharmacology, Faculty of Medicine of Mons, University of Mons, Mons 7000, Belgium c Department of Anatomy and Pathology, Charles Nicolle Hospital, Tunis 1007, Tunisia A R T I C L E I N F O Article history: Received 7 February 2017 Received in revised form 21 March 2017 Accepted 6 April 2017 Keywords: Lung fibrosis Nigella sativa oil Metabonomics Urine TGFb Inflammation A B S T R A C T The present study investigated the effects of Nigella sativa oil (NSO) on bleomycin (BLM)-induced lung fibrosis in rats. The rat model of pulmonary fibrosis (PF) was established by intratracheal instillation of BLM, and the effect of 1 ml/kg oral NSO treatment once daily observed. The effect of NSO was studied over a period of 50 days using 1 H RMN analysis on the urine and broncho alveolar lavage fluid (Balf) of the rats. Histopathological (inflammation and fibrosis) and immunohistochemical (TGF-b1 density) changes were evaluated. Results found that the BLM group showed a significant increase in inflammatory index (II), fibrosis score (FS) and TGF-b1 distribution in the lung inflammatory infiltrate, accompanied by a decreased urinary secretion of Krebs cycle intermediates, including acetate, pyruvate, carnitine, trimethylamine-N- oxide and succinate. However, at the same time point, NSO treated rats had a reduced II and FS, and had an increased urinary secretion of histidine, fumarate, allantoin and malate. In conclusion, NSO treatment attenuated the effects of BLM-induced PF, by supporting lung, liver and kidney activity in resisting PF. These findings provide an insight into the preventive and therapeutic potential of NSO in the treatment of PF. © 2017 Elsevier Masson SAS. All rights reserved. 1. Introduction Pulmonary fibrosis (PF) is a chronic and incapacitating lung disease, which results in progressive scarring of the alveolar tissue that leads to trouble breathing [1]. In the characteristic pathologi- cal process of PF, normal tissue is replaced with mesenchymal cells and the extracellular matrix that these cells produce [2]. PF can be caused as a side effect of certain drugs such as bleomycin (BLM) or as a complication of autoimmune diseases, such as rheumatoid arthritis. BLM is an antineoplastic agent used for the treatment of a number of tumors. Frequent and repeated administration of BLM can cause lung inflammation, which can eventually progress into fibrosis [3]. The first sign of a fibrous lesion caused by BLM is a strong inflammatory response, which involves neutrophils, macrophages and T cells [4]. In response to inflammation and oxidative stress, a number of cytokines and inflammatory mediators are released by the damaged lung tissue, stimulating the formation of myofibroblasts and the accumulation of collagen in the extracellular matrix [5]. The primary treatment for PF is corticosteroids with a combination of immunosuppressant, anti-inflammatory, anti-fibrosis, antioxi- dant and anticoagulant drugs. However, treatment success is limited [6]. In a clinical trial, treatment with interferon-g reduced the mortality rate of patients with PF, although it did not show any direct effect on fibrosis [7]. Consequently, finding an effective treatment for PF remains a challenge, and the development of novel antifibrotic drugs is vital [8]. Recently, experimental models of BLM-induced lung fibrosis have been used to investigate potential anti-fibrotic agents, including pirfenidone [9], PG490-88 [10] and LLDT-8 [11]. Despite the fact that these agents originate from different backgrounds (pirfenidone is a pyridine ketone, and PG-490-88 and LLDT-8 are derivatives of triptolide) they possess similar anti-fibrotic, antioxidant and anti-inflammatory activities. However, the exact mechanisms through which PG-490-88 and LLDT-8 provide protection against lung fibrosis remain unclear and * Corresponding author at: Laboratory of Physiology, Faculty of Medicine of Tunis, University of Tunis El Manar, 15 Djebel Lakhdar, La Rabta, Tunis 1007, Tunisia. E-mail address: abidi_anouar3@yahoo.fr (A. Abidi). http://dx.doi.org/10.1016/j.biopha.2017.04.009 0753-3322/© 2017 Elsevier Masson SAS. All rights reserved. Biomedicine & Pharmacotherapy 90 (2017) 626–637 Available online at ScienceDirect www.sciencedirect.com