Objective　To investigate the effect of Geminin on phenotype transformation of vascular smooth muscle cells (VSMC) in rats by comparing the expressions of Geminin in resting and serum-simulated VSMC．　Methods　VSMC were divided into control group (serum starvation group) and serum stimulation group. Differences in distribution

activity

and expression of Geminin were studied between the two groups．Serum starvation was used to induce phenotype differentiation and activity of Geminin. Expression of Geminin was detected by PCR while expression of Geminin protein

synthetic biomarker osteopontin (OPN)

SM-2 actin-related proteins (ARP) was detected by Western blotting．　Results　The contractible form of VSMC was mainly observed in control group followed by synthetic form after serum stimulation. Almost all kinds of resting Geminin were found in cytoplasm and located in nuclei after serum stimulation. The expression levels of Geminin mRNA and protein as well as OPN were significantly higher after serum stimulation than before serum stimulation

especially 48 h after serum stimulation (P0.05). 　Conclusion　Geminin participates in transforming VSMC from contractile to synthetic form．