Paeoniflorin suppresses the phenotypic transformation of vascular smooth muscle cells during atherosclerosis by regulating the MAPK/NF-κB pathways and ABCA1 expression.

BACKGROUND: The pathological environment of atherosclerosis (AS) is characterized by hyperlipidemia and chronic inflammation, which cause increased heterogeneity among vascular smooth muscle cells (VSMCs). Owing to its lipid-regulating and anti-inflammatory effects, paeoniflorin (Pae) inhibits VSMC phenotypic transformation, making it a promising candidate for AS treatment.

METHODS: Mouse aortic VSMCs were treated with oxidized low-density lipoprotein (ox-LDL) and Pae, and the effects on cell phenotype were examined. An AS model was established by feeding ApoE-/- mice a high-fat diet. Serum and tissue samples were collected for analysis after treatment with or without Pae oral administration.

RESULTS: Pae reversed weight gain and elevated TG levels in the AS model. Oil Red O staining showed that Pae inhibited VSMC-derived foam cell formation in vitro and reduced aortic sinus plaque area, aortic wall lipid deposition, and hepatic steatosis in the AS model. Immunofluorescence staining of the aortic sinus revealed that Pae mitigated α-SMA overexpression and reversed ATP-binding cassette transporter A1 (ABCA1) downregulation. Western blotting analysis revealed that Pae inhibited ERK1/2 and p65 phosphorylation, curbed MMP2 overexpression, and restored downregulated ABCA1 expression. Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine staining, and wound healing assays demonstrated that Pae inhibited ox-LDL-induced VSMC proliferation and migration. Additionally, Pae significantly inhibited the expression of the inflammatory factors IL-6 and MCP-1 both in vivo and in vitro.

CONCLUSIONS: Pae may treat AS by inhibiting VSMC phenotypic transformation.