Plumbagin attenuates Bleomycin-induced lung fibrosis in mice

Background Idiopathic pulmonary fibrosis (IPF) is a fatal fibrotic lung disease with limited treatment options. Plumbagin (PL) is an herbal extract with diverse pharmacological effects that have been recently used to treat various types of cancer. This study aims to explore the anti-fibrotic effect of PL and possible underlying mechanisms in IPF. Methods We used a bleomycin-induced experimental mouse model of lung fibrosis to assess the potential anti-fibrotic effect of PL. Histological analysis of lung tissue samples by H&E and Masson's trichrome staining and hydroxyproline assay was performed to evaluate the fibrotic alterations. ELISA and real-time quantitative PCR were conducted to determine the amount of tumor necrosis factor-alpha (TNF[alpha]), tumor growth factor-beta (TGF-[beta]), connective tissue growth factor (CTGF), and endothelin-1 (ET-1). Results Bleomycin exposure induced lung fibrosis, which was indicated by inflammation, collagen deposition, and structural damage. PL remarkably prevented bleomycin-induced lung fibrosis. Furthermore, PL significantly inhibited TNF-[alpha] and TGF-[beta] production. PL also diminished the upregulated expression of CTGF and ET-1 induced by bleomycin. Conclusion Overall, our findings suggest PL as an anti-fibrotic agent acting via down-regulation of TGF-[beta]/CTGF or ET-1 axis, as well as TNF-[alpha], to improve lung fibrosis. Keywords: Plumbagin, Inflammation, Fibrosis, Bleomycin, Idiopathic pulmonary fibrosis