Amelioration of bleomycin induced pulmonary fibrosis by administration of Salvianolic acid B in mice

Pulmonary fibrosis is the end-stage manifestation of wide range of respiratory diseases and during pulmonary fibrosis, pulmonary inflammation and epithelial-mesenchymal transition (EMT) play important roles. Salvianolic acid B (SAB) from the herb Salviae miltiorrhiza has been reported to possess an excellent anti-inflammatory, antifibrotic and antioxidant activity. The present study aimed to investigate the ameliorative effect of SAB on bleomycin induced pulmonary fibrosis in mice. Adult albino mice were divided as SHAM/ control group (saline alone), BLM group (bleomycin @ 1mg/kg intratracheally once) and SAB groups (BLM challenged once and SAB administration in three dosages @ 5, 10 and 15 mg/kg intraperitoneally daily for 30 days). Lungs wet/dry ratio and protein concentration in bronchoalveolar lavage fluid, MPO activity, oxidative stress markers, hydroxyproline assay, levels of inflammatory cytokines ( TNF-a, IL-6 and TGF-ss 1), NF-.B activity, histopathology, immunostaining (E-cadherin, vimentin and alpha -smooth muscle actin) and ultrastructural changes were studied. SAB showed anti-inflammatory and anti-fibrotic effects through inhibition of inflammatory cell infiltration, alveolar structure disruption, and collagen deposition and the expression of several fibrogenic cytokines. SAB also up-regulate E-cadherin and down-regulated vimentin and alpha-smooth muscle actin expression. In conclusion, Salvianolic acid B is effective in alleviating the BLM induced lung fibrosis through suppression of oxidative stress, inflammation, histological, ultrastructural changes and EMT.