TGF-β1 production in ASMCs and the effect of TGF-β1 on proliferation of ASMCs. (A) Supernatants were collected after culture for 24 hours. Cytokine TGF-β1 was measured by ELISA. Data are expressed as mean ± SD for each group. (*P < 0.05 versus control). (B) Proliferation of ASMCs in each group was measure by CCK-8 assay. Data are expressed as mean ± SD for each group. TGF-β1 significantly promoted cell proliferation, which could be inhibited by PD98059, wortmannin and β-CD (*P < 0.05 versus control and asthma group, #P < 0.05 versus control group, **P < 0.05 versus TGF-β1 group). No significant change between inhibitor group and TGF-β1 + inhibitor group was observed.