Abstract: AIM: To investigate the effect of salvianolic acid B on TGF-β₁-induced proliferation and differentiation in lung fibroblasts. METHODS: The human embryonic lung fibroblasts (MRC-5) were randomly divided into six groups as follows: control group (cells cultured with DMEM without TGF-β₁ or Sal B); Sal B groups (cells cultured with 1 μmol/L or 10 μmol/L Sal B); TGF-β₁ group (cells cultured with 10 ng/mL TGF-β₁); TGF-β₁ (10 ng/mL) with 1 or 10 μmol/L of Sal B treated groups. The cell proliferation rates were analyzed by MTT assay. The protein levels of α-SMA were detected by Western blot, and the expressions of α-SMA mRNA were evaluated by RT-PCR.The expression of F-actin was detected by immunofluorescence. RESULTS: TGF-β₁ treatment of lung fibroblasts increased cell proliferation rates and α-SMA expression, changed cell morphology from a spindle shape to a stellate shape, and induced F-actin reorganization to form abundant long stress fibers (P<0.01 as compared with control). The treatment with only Sal B did not affect the proliferation, α-SMA expression, cell morphology and F-actin reorganization of lung fibroblasts (P>0.05 as compared with control). Sal B was found to inhibit TGF-β₁-induced cell proliferation, α-SMA expression, cell morphology change, and F-actin reorganization in lung fibroblasts (P<0.05 as compared with TGF-β₁ group). The inhibitory effect of Sal B on TGF-β₁-induced proliferation and differentiation in lung fibroblasts was more significant with the treatment of high-dose Sal B (1 vs 10 μmol/L, P<0.05). CONCLUSION: Sal B could inhibit TGF-β₁-induced cell proliferation and differentiation in lung fibroblasts in vitro.

Key words: salvianolic acid B, pulmonary fibroblast, transforming growth factor-β₁;, proliferation, differentiation