Total extract of Anemarrhenae Rhizoma attenuates bleomycin-induced pulmonary fibrosis in rats

Pulmonary fibrosis is a progressive interstitial lung disease with poor prognosis. Anemarrhenae Rhizoma is a traditional Chinese herbal medicine and has been applied in clinical practice for a long history. Recently, components of Anemarrhenae Rhizoma were reported to possess anti-inflammatory and immunomodulatory features; however, the effect of them on pulmonary fibrosis remains unknown. In this study, we explored the therapeutic effect of total extract of Anemarrhenae Rhizoma (TEAR) on bleomycin-induced pulmonary fibrosis. Pulmonary fibrosis rat model was established by a single intratracheal instillation of bleomycin, three doses of TEAR were intragastrically administered for consecutive 28 days. Subsequent to sacrificing of rats, pulmonary fibrosis was observed in rats treated with bleomycin, but administration of TEAR attenuated lung fibrosis, as evidenced by the improved lung histopathological damage and decreased weight loss and lung index. Moreover, TEAR treatment inhibited the inflammatory response in lung fibrosis, which was shown by the reduced nitrogen oxide level and myeloperoxidase activity. Furthermore, TEAR modulated the redox balance in lung tissue by alleviated lipid peroxidation and enhanced enzymatic antioxidants activity. Meanwhile, TEAR protected the rats from fibrosis in a dose-dependent manner, and the anti-fibrotic activity of TEAR may be related to the modulation of TGF-β1/Smad signaling pathway. Collectively, TEAR alleviates bleomycin-induced pulmonary fibrosis, indicating perspectives for development of a potential agent for lung fibrosis therapy.