Abstract: AIM: To investigate the effects of 12-degree of polymerization heparin oigosaccharid (dp12) on proliferation in vascular smooth muscle cells (VSMCs) and to analyze their activated signal transduction pathways.METHODS: In this study, the proliferation of VSMCs of bovine thoracic aorta was induced by 10% NCS and the effects of dp12 on VMSCs proliferation followed upon different concentrations. MTT assay was evaluated to indicate the proliferation of VSMCs; flow cytometry was used to detect the cell cycle; the ERK mRNA and phosphor protein of ERK were detected by reverse transcription polymerase chain reaction (RT-PCR) and western-blotting respectively.RESULTS: MTT assay showed the inhibitory effects of dp12 on VSMCs induced by 10% NCS; flow cytometry revealed that the inhibited proliferation was a result of the interference of VSMCs entering S phase from G₁ phase; western-blotting and RT-PCR profiles proved that dp12 inhibited the transcription and phosphorylation of ERK1/2.CONCLUSION: 12-Degree of polymerization heparin oigosaccharid inhibits the VSMCs entering S phase from G₁ phase, it also inhibits the transcripttion and phosphorylation of ERK1/2, which might be the putative anti-proliferation mechanism of VSMCs.

Key words: Heparin oigosaccharide, Proliferation, Vascular smooth muscle cells, ERK1/2