Effects of Danshensu on TGF-β_1/Smads signaling pathways in rats with pulmonary fibrosis

AIM: To study the preventive and curative roles of Danshensu(DA) in bleomycin(BLM)-induced pulmonary fibrosis in rats.METHODS: Pulmonary fibrosis was induced in SD rats by intratracheal instillation of BLM.The rats were intraperitoneally injected with dexamethasone(1 mg·kg-1·d-1,DXM group),DA(15 mg·kg-1·d-1,DA group),or physiological saline(2 mL·d-1,BLM group).Normal controls(NC group) received physiological saline both intratracheally and intraperitoneally.At the 28th day after modeling,the histological changes of the lungs were evaluated by hematoxylin-eosin(HE) and Masson's trichrome staining.The protein levels of α-smooth muscle actin(α-SMA) in the lung tissues were detected by the method of immunohistochemistry.The mRNA expression of transforming growth factor beta 1(TGF-β1),Smad3 and Smad7 was assessed by real-time fluorescence quantitative PCR.RESULTS: Compared with BLM group,the degree of inflammation and fibrosis of the lung in DA group was obviously reduced,and so was the expression of α-SMA in the lung tissues.The mRNA expression of TGF-β1 and Smad3 in the lung tissues of the rats decreased and the mRNA expression of Smad7 increased.CONCLUSION: DA alleviates BLM-induced pulmonary fibrosis in rats in the early stage by inhibiting the expression of TGF-β1/Smad3 and stimulating the expression of Smad7 in the lung tissues.