PDGF-CC is the major factor underlying DM-MCM-induced SMC proliferation.

(A) Prior to culturing under control conditions (CL) or stimulation with DM-MCM, the DM-MCM and SMCs were pre-incubated with isotype-matched IgG or neutralizing antibodies against PDGF-BB (Ab-BB) or PDGF-CC (Ab-CC) individually for 2 h, and then stimulated with DM-MCM for 24 h. Cell proliferation was assayed by the MTT test from 3 independent experiments. *P<0.05 versus CL. ^#P<0.05 versus IgG-treated SMCs under DM-MCM stimulation. (B) The expression levels of PDGF-BB and PDGF-CC in MCM were determined by sandwich ELISA from 3 independent experiments. *P<0.05 versus NC-MCM. (C, D) SMCs were kept as CL or stimulated with 50% DM-MCM for 48 h. The proliferation of SMCs was obviously promoted by PDGF-CC at 50 and 100 ng/mL, and the promoting effect was inhibited by the neutralizing antibody against PDGF-CC (Ab-CC) (D). PDGF-BB has no significant effect on promoting SMC proliferation (C). Cell proliferation was assayed by the MTT assay from 3 independent experiments. *P<0.05 versus CL. ^#P<0.05 versus 50% DM-MCM-treated SMCs. **P<0.05 versus 50% DM-MCM-treated SMCs.