Objective        To investigate the proliferation and phenotypic markers of rat vascular smooth muscle cells (VSMCs) by using RNA interference targeting geminin.       Methods       VSMCs were  transfected with siRNA for knockdown of geminin. Changes of geminin  at protein and mRNA levels were detected by Western blotting and RT-PCR

and siRNA-geminin that exhibited the most significant inhibitory effect was used to construct lentivirus-packaged stable interference model. The

proliferation of VSMCs was observed by [

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-TdR and EdU incorporation. The changes of phenotype-dependent markers  were analyzed by Western blotting.       Results       After VSMCs transfected with three pairs of siRNA targeting geminin

a significant decrease of geminin expression was observed in one pair

as compared with that of the other two pairs and the controls (P0.05). [

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-TdR and EdU incorporation showed a higher proliferation index in the positive interference group than that in the control groups (P0.05). In the positive interference group

level of synthetic marker osteopontin (OPN) increased and level of contractile marker smooth muscle actin (α-Actin) decreased

and the differences were significant as compared with those of the control groups (P0.05).       Conclusion      Geminin silencing by siRNA can promote VSMCs proliferation and phenotype transformation from contractile phenotype to synthetic phenotype.