〔Abstract〕 Objective To investigate the effect of secreted protien acidic and rich in cysteine(SPARC) gene on the proliferation and apoptosis of human keloid fibroblasts and its mechanismin vitro.Methods The lentiviral vector carrying SPARC shRNA(LV2 N-shRNA-SPARC,sh-SPARC group)and empty plasmid(LV2-NC,sh-NC group)were transfected into human keloid fibroblasts(HKF) respectively. Real-time PCR(qRT-PCR) and Western blot were performed to examine the expression of SPARC mRNA and protein in HKF. MTT assay was used to estimate the cell proliferation. The cell cycle and apoptosis of HKF were detected by flow cytometry. The expression of TGF-β1 and TβRⅠ proteins in HKF were detected by Western blot.Results(1) After transfection of SPARC shRNA lentiviral vector, the expression of SPARC mRNA and protein in HKF were significantly down-regulated compared with those in the control groups(P<0.05).(2) MTT assay showed that the proliferation of sh-SPARC groups decreased compared with the control groups(P<0.05).(3) Flow cytometry results showed that the S phase cell ratios of sh-SPARC groups were reduced while the apoptosis rates increased compared with the control groups(P<0.05).(4) Western blot showed that the protein expression levels of TGF-β1 and TβRⅠsignificantly decreased in shSPARC groups.Conclusion SPARC gene silencing inhibits the proliferation blocks cell cycle progression and promotes cell apoptosis in HKF, which may be related to the down-regulation of the TGF-β signaling pathway.