[The phenotypic switching of vascular smooth muscle cells induced by cholesterol]

To observe the effect of cholesterol on phenotypic switching of human vascular smooth muscle cells (VSMCs) in vitro.

VSMCs were treated with cholesterol at 12.5, 25.0 and 50.0 mg/L for 48 hours and at 50 mg/L for 24, 48 and 72 hours. Real-time quantitative PCR and Western blotting were respectively applied to detect the mRNA expressions of smooth muscle alpha-actin (α-SMA), smooth muscle 22 alpha (SM22α) and the protein expressions of SM22α, monocyte chemotactic protein-1 induced protein (MCPIP). CCK-8 assay was performed to analyze the viability of VSMCs.

Compared with control groups, cholesterol treatments resulted in a significant down-regulation of both mRNA and protein expressions of endogenous α-SMA and SM22α in VSMCs at 48 hours (P<0.05), and the expressions were lowest when cholesterol was 50.0 mg/L. At 48 and 72 hours, 50.0 mg/L cholesterol significantly decreased the expressions of α-SMA and SM22α (P<0.05). The proliferation of VSMCs in cholesterol groups was promoted significantly compared with control groups (P<0.05). Cholesterol at 50.0 mg/L was also able to induce MCPIP protein expression in VSMCs at 48 hours (P<0.05).

Cholesterol can decrease the expressions of α-SMA and SM22α and enhance the proliferation of VSMCs, which suggests that cholesterol induces phenotypic switching of VSMCs.