Sulforaphane prevents bleomycin‑induced pulmonary fibrosis in mice by inhibiting oxidative stress via nuclear factor erythroid 2‑related factor‑2 activation

• Published in: Molecular medicine reports Vol. 15; no. 6; pp. 4005 - 4014
• Main Authors: Yan, Bingdi, Ma, Zhongsen, Shi, Shaomin, Hu, Yuxin, Ma, Tiangang, Rong, Gao, Yang, Junling
• Format: Journal Article
• Language: English
• Published: Greece Spandidos Publications 01.06.2017; Spandidos Publications UK Ltd; D.A. Spandidos
• Subjects: 4-Hydroxynonenal; Alveolar Epithelial Cells - drug effects; Alveolar Epithelial Cells - metabolism; Alveolitis; Animal models; Animals; Antioxidants; Apoptosis; Apoptosis - drug effects; Bleomycin; Bleomycin - adverse effects; Caspase; Caspase-3; Catalase; Collagen; Cyanates; Cytokines; Disease Models, Animal; DNA nucleotidylexotransferase; Enzymes; Epithelial cells; Fibroblasts; Fibrosis; Gene Expression; Genes; Health aspects; Heme; Heme oxygenase (decyclizing); Inflammation; Isothiocyanates - pharmacology; Lung diseases; Lungs; Male; Metastases; Mice; NF-E2-Related Factor 2 - genetics; NF-E2-Related Factor 2 - metabolism; NRF2 protein; Oxidative stress; Oxidative Stress - drug effects; Oxidoreductase; Oxygenase; Prevention; Protective Agents - pharmacology; Protein expression; Proteins; Pulmonary fibrosis; Pulmonary Fibrosis - etiology; Pulmonary Fibrosis - metabolism; Pulmonary Fibrosis - pathology; Pulmonary Fibrosis - prevention & control; Rodents; Studies; Sulforaphane; Superoxide dismutase; Toxicity; Transcription factors; Transforming growth factor-b
• ISSN: 1791-2997; 1791-3004
• DOI: 10.3892/mmr.2017.6546

Lung fibrosis is associated with inflammation, apoptosis and oxidative damage. The transcription factor nuclear factor erythroid 2‑related factor‑2 (Nrf2) prevents damage to cells from oxidative stress by regulating the expression of antioxidant proteins. Sulforaphane (SFN), an Nrf2 activator, additionally regulates excessive oxidative stress by promoting the expression of endogenous antioxidants. The present study investigated if SFN protects against lung injury induced by bleomycin (BLM). The secondary aim of the present study was to assess if this protection mechanism involves upregulation of Nrf2 and its downstream antioxidants. Pulmonary fibrosis was induced in C57/BL6 mice by intratracheal instillation of BLM. BLM and age‑matched control mice were treated with or without a daily dose of 0.5 mg/kg SFN until sacrifice. On days 7 and 28, mice were assessed for induction of apoptosis, inflammation, fibrosis, oxidative damage and Nrf2 expression in the lungs. The lungs were investigated with histological techniques including haematoxylin and eosin staining, Masson's trichrome staining and terminal deoxynucleotidyl transferase UTP nick end labeling. Inflammatory, fibrotic and apoptotic processes were confirmed by western blot analysis for interleukin‑1β, tumor necrosis factor‑α, transforming growth factor‑β and caspase‑3 protein expressions. Furthermore, protein levels of 3‑nitro‑tyrosine, 4‑hydroxynonenal, superoxide dismutase 1 and catalase were investigated by western blot analysis. It was demonstrated that pulmonary fibrosis induced by BLM significantly increased apoptosis, inflammation, fibrosis and oxidative stress in the lungs at days 7 and 28. Notably, SFN treatment significantly attenuated the infiltration of the inflammatory cells, collagen accumulation, epithelial cell apoptosis and oxidative stress in the lungs. In addition, SFN treatment increased expression of the Nrf2 gene and its downstream targets. In conclusion, these results suggested that SFN treatment of pulmonary fibrosis mouse models may attenuate alveolitis, fibrosis, apoptosis and lung oxidative stress by increasing the expression of antioxidant enzymes, including NAPDH quinone oxidoreductase, heme oxygenase‑1, superoxide dismutase and catalase, via upregulation of Nrf2 gene expression. Thus, the results from the present study may facilitate the development of therapies for BLM‑toxicity and pulmonary fibrosis.