Salvia miltiorrhiza Bunge extract and Przewalskin ameliorate Bleomycin-induced pulmonary fibrosis by inhibition of apoptosis, oxidative stress and collagen deposition via the TGF-β1 pathway

Salvia miltiorrhiza Bunge (Labiatae) (DS) is a key part of the traditional Chinese medicine, whose roots are used to remove blood stasis, relieve pain, eliminate carbuncle and calm the nerves. Our research team found that the DS extract could significantly reverse LPS-induced lung injury, and five new diterpenoid quinones in DS extract with excellent lung protective activity for the first time. However, the material basis and mechanism of DS on pulmonary fibrosis (PF) needs to be explored in depth. Bleomycin (BLM) was employed to establish the PF model, and Transcriptome and Surface plasmon resonance (SPR) ligand fishing technology were used to explore the material basis and mechanism of DS on PF, and provided theoretical research for clinical treatment of PF. DS extract (24.58 or 49.16 mg/kg, i.g.) was administered daily from Day 8 to Day 28, followed by intratracheal BLM drip (5 mg/kg) to induce PF. Data about the influences of DS on PF were collected by transcriptome sequencing technology. Pulmonary ultrasound, airway responsiveness, lung damage, collagen deposition, and the levels of TNF-α, IL-1β, apoptosis, oxidative stress (OS), immune cells, TGF-β1, α-SMA, E-Cadherin and Collage Ⅰ were examined. The affinity component (Przewalskin) in DS extract targeted by TGF-β1 was fished by SPR ligand fishing technology. Furthermore, an in vivo PF mouse model and an in vitro TGF-β1 induced BEAS-2B cell model were established, to explore the mechanism of Przewalskin on PF from the apoptosis, OS and epithelial mesenchymal transformation pathway. DS extract improved pulmonary ultrasound, reduced lung damage and collagen deposition, downregulated TNF-α, IL-1β, apoptosis, OS, TGF-β1, α-SMA, E-Cadherin and Collage Ⅰ, transformed immune cells following Bleomycin challenge. Furthermore, affinity component (Przewalskin) also improved pulmonary ultrasound and airway responsiveness, reduced lung damage and collagen deposition, downregulated TNF-α, IL-1β, apoptosis, OS in vivo and in vitro. Analysis using a mouse model revealed that DS extract and Przewalskin can relieve clinical symptoms of PF, reduce lung injury and improve lung function. Meanwhile, DS extract and Przewalskin can improve BLM-induced PF by inhibition of, OS, apoptosis and collagen deposition might via the TGF-β1 pathway. This study provides references to identification of novel therapeutic targets, thereby facilitating drug development for PF.