Aim To investigate the effects of Stichopus Variegates on proliferation and apoptosis induced by platelet-derived growth factor-BB(PDGF-BB)in rat vascular smooth muscle cells(VSMC),and to explore its mechanism of anti-atherosclerosis role,prevention from restenosis after percutaneous transluminal coronary angioplasty(PTCA).Methods The tissue plate method was employed to culture rat thoracic aorta smooth muscle cells in vitro.The effects of Stichopus Variegates on proliferation were analysed using methyl thiazolyl tetrazolium(MTT)colorimetry and flowcytomerty.Cell apoptosis was investigated by flowcytomerty and TUNEL methods.Results Treatment of VSMC with PDGF-BB led to promote proliferation and suppress apoptosis,oppositely Stichopus Variegates significantly reversed these effects.MTT colorimetry showed mean OD value decreased from 0.406±0.003 to 0.187±0.017(p<0.01).Flow cytometry showed the percentage of G0/G1 phase cells increased from 77.4%±5.7% to 88.1%±5.3%(p<0.05)and the percentage of apopototic cells increased from 8.6%±2.3% to 22.6%±2.3%(p<0.05).TUNEL results showed that the percentage of apopototic cells increased from 2.7%±0.4% to 10.1%±0.9%(p<0.01).Conclusion Stichopus Variegates significantly inhibited PDGF-induced proliferation and promoted cell apoptosis of VSMC,which may play important roles in the prevention of atherosclerosis and restenosis after PTCA in vivo.