Objective: The purpose of the study was to explore the effect of Bufei Yishen formula (BFYS) on cellular proliferation of pulmonary artery smooth muscle cells induced by transforming growth factor-β1 (TGF-β1)/bone morphogenetic protein-4 (BMP-4)

furthermore

to explore the effect of BFYS on TGF-β1/Smad signaling pathway in the cells. Method: TGF-β1/BMP-4was used to induce proliferation of human pulmonary artery smooth muscle cells. The cells were divided normal group (10% normal rat serum)

induced-proliferation group(10% normal rat serum with 7.5 μg·L-1TGF-β1 and 5 μg·L-1BMP-4)

4% BFYS serum group(6% normal rat serum with 7.5 μg·L-1TGF-β1 and 5 μg·L-1BMP-4 and 4% BFYS rat serum)

6% BFYS serum group (4% normal rat serum with 7.5 μg·L-1TGF-β1 and 5 μg·L-1BMP-4 and 6% BFYS rat serum) and 8% BFYS serum group (2% normal rat serum with 7.5 μg·L-1TGF-β1 and 5 μg·L-1BMP-4 and 8% BFYS rat serum). After 24 h induction

cell density was observed under a microscope; 5-bromo-2-deoxyuridine(BrdU) was used to detect the cellular proliferation;Western blot was used to detect the Smad 1

2

3

5 and p-Smad2/3 protein expression

and Real-time PCR was used to detect plasminogen activator inhibitor-1 (PAI-1)

connective tissue growth factor(CTGF)

dominant negative helix-loop-transcription factors-1 (ID-1)and ID-2 mRNA expression. Result: After 24 h of TGF-β1/BMP-4 treatment

the cells density was increased under micro-examination with significant increase in cellular proliferation ratio (P<0.05). BFYS inhibited TGF-β1/BMP-4-induced cellular proliferation in a dose dependent manner

with significant decrease in 8% concentration group(P<0.01). Both TGF-β1/BMP-4 and BFYS showed no significant effect on Smad1

2

3 and 5 proteins expression. However

p-Smad2/3 expression was significant increased by TGF-β1/BMP-4 induction (P<0.05) and 8% BFYS significantly reduced its expression (P<0.05). For assays of down-scream genes expression of TGF-β1/Smad pathway

TGF-β1/BMP-4 and BFYS showed no significant effect on PAI-1

ID-1and ID-2 mRNA expression. But TGF-β1/BMP-4 increased CTGF mRNA expression (P<0.01) and 8% BFYS inhibited TGF-β1/BMP-4 induced CTGF mRNA expression (P<0.05). Conclusion: BFYS reduced TGF-β1/BMP-4 induced cellular proliferation of human pulmonary arterial smooth muscle cells

and its mechanisms might be associated with inhibiting p-Smad2/3/CTGF pathway.