[Saikosaponin D inhibits proliferation and collagen production of human embryonic lung fibroblasts by regulating TGF-β1/Smads signaling pathway].

Objective To investigate the effect of saikosaponin D (SSD) on the proliferation and transformation of human embryonic lung fibroblasts (HELFs) induced by transforming growth factor-beta 1 (TGF-β1) and the regulation of signal pathway of TGF-β1/Smads family. Methods HELFs were cultured in vitro and divided into 5 groups: a control group, 1 ng/mL TGF-β1-induced group, 1 ng/mL TGF-β1 combined with 0.5 μmol/L SSD treatment group, 1 ng/mL TGF-β1 combined with 1 μmol/L SSD treatment group, and 1 ng/mL TGF-β1 combined with 2 μmol/L SSD treatment group. Cell viability of HELFs was detected by CCK-8 assay. The expression of Smad2, Smad3 and Smad7 mRNA were detected by real-time fluorescence quantitative PCR. The protein levels of α-smooth muscle actin (α-SMA), type 1 collagen (Col1), Smad2, Smad3, phosphorylated Smad2 (p-smad2), p-smad3 and Smad7 were assessed by Western blot analysis. Results Compared with the control group, TGF-β1-induced group showed the apparently increased proliferation ability, the increased protein levels of Col1 and α-SMA, the significantly increased mRNA and protein phosphorylation levels of Smad2 and Smad3, and the significantly decreased mRNA and protein expression of Smad7. Compared with the TGF-β1-induced group, the cell proliferation of HELFs in different concentrations of SSD treatment groups was reduced, which could reverse the changes of the above indicators in a dose-dependent manner. Conclusion SSD plays an important role in anti-pulmonary fibrosis by regulating TGF-β1/Smads signaling pathway.