Abstract: The aim of this study was to investigate the functions and regulatory pathway of gypenosiedes (GP) on vascular smooth muscle cells (VSMCs) phenotype in hyperlipidemic rats.Hyperlipidemic rats model were established by feeding rats with high-fat diet.Blood lipid levels were detected in all groups.The ultrastructure of VSMCs was detected by transmission electron microscope.The expression of smooth muscle actin(SM-actin),proliferating cell nuclear antigen (PCNA) and monocyte chemotactic protein-1 induced protein (MCPIP1) in VSMCs were determined by using immunohistochemistry staining and Western blot methods.The experimental results showed that GP can decrease the blood lipids levels.GP effectively attenuated dedifferentiated changes of VMSCs ultrastructure and increased the expression of SMactin.The expressions of PCNA and MCPIP1 in VSMCs were both decreased in GP group.These results demonstrate a novel protection role of GP in VSMCs dedifferentiation by inhibiting MCPIP1 expression.

Key words: gypenosides, vascular smooth muscle cell, phenotype, monocyte chemotactic protein-1 induced protein 1