Abstract: AIM:To explore primary culture and subculture methods of vascular smooth muscle cells (VSMCs) from human saphenous vein (SV) and internal thoracic artery (ITA) and to compare their growth characteristics in vitro. METHODS: SV and ITA tissues were obtained from patients undergoing coronary artery bypass grafting. VSMCs were primarily cultured by explant attached method and then were identified by immunofluorescence staining. Cell culture time of SV VSMCs and ITA VSMCs were compared and analyzed. After 48 h serum deprived culture, SV VSMC and ITA VSMC growth was observed under different conditions of DMEM/F12, 10% FBS and 10 ng/ml PDGF-BB and cell proliferations were compared by MTT assay. RESULTS: The primary and subculture were successfully completed. Positive staining of SMα-actin in the cytoplasm was shown by immunofluorescence (positive rate of >95%). Primary cultured VSMC growth from the edge of SV tissue clumps after incubation was slower than that of ITA ［(9.1±1.1) vs.(5.8±1.0) days, P<0.05］. The first passage time of SV VSMCs (34.9±3.4) days was longer than that of ITA VSMCs (29.1±4.4) days, P<0.05 and the re-passage time of SV VSMCs (9.0±4.2) days was similar to that of ITA VSMCs (9.6±3.9) days. No significant morphological difference was observed between SV VSMCs and ITA VSMCs under the same culture conditions and no significant difference was found in the relative cell growth curves. CONCLUSION: VSMC primary culture of SV and ITA by explant attached method is feasible. VSMCs in vivo present good cell phenotype transformation characteristics and can be used as a good cell model for molecular mechanism study of restenosis after coronary artery bypass surgery. SV VSMCs may have stronger proliferation potentials than ITA VSMCs. The intrinsic difference of VSMCs from SV and ITA still needs further study.