Dahuang zhechong pill containing serum inhibited platelet-derived growth factor-stimulated vascular smooth mscle cells proliferation by inducing G1 arrest partly via suppressing protein kinase C a-extracellular regulated kinase 1/2 signaling pathway

Objective: To investigate effects of Dahuang Zhechong Pill (DHZCP) on the cell cycle and the related signal pathways in vascular smooth muscle cells (VSMCs) stimulated by platelet-derived growth factor (PDGF) with the method of serum pharmacology. Methods: DNA synthesis in VSMCs was examined by detecting 5′-bromo-2′-deoxyuridine incorporation with the immunocytochemical method. The cycle of VSMCs was evaluated with flow cytometry. Expressions of cyclin D1, p27, protein kinase Ca (PKCα), and phosphorylated extracellular signal regulated kinase 1/2 (ERK1/2) were quantified by Western blot method. Results: DHZCP containing serum significantly inhibited DNA synthesis of PDGF-stimulated VSMCs, arrested the cells in G1 phase, modulated the protein expressions of cyclin D1 and p27, and suppressed the activation of PKCa and ERK1/2. Conclusion: DHZCP containing serum inhibits VSMCs proliferation via modulating the expressions of cell cycle proteins to arrest the cell in G ₁ phase, which is attributed to, at least in part, suppressing PKCa-ERK1/2 signaling in VSMCs.