Effects Of Downregulating SPARC Expression On Proliferation And Apoptosis Of Keloid Fibroblasts

Objective To investigate the effects of Secreted Protien Acidic and Rich in Cysteine（SPARC）on the proliferation and apoptosis of human keloid fibroblasts and its mechanism in vitro.Methods The lentiviral vector carrying SPARC shRNA and empty plasmid were transfected into human keloid fibroblasts respectively.Real-time PCR and Western blot were performed to detect the expression of SPARC m RNA and protein in human keloid fibroblasts.MTT assay was used to estimate the cell proliferation.The cell cycle and apoptosis of HKF cells were detected by flow cytometry.In addition,the expression of TGF-β1 and TβRⅠ proteins in HKF cells were detected by Western blot.Results After transfection of SPARC shRNA lentiviral vector,the expression of SPARC m RNA and protein in HKF cells were significantly down-regulated compared with those in control groups.Silencing SPARC inhibited the proliferation.After SPARC gene silencing the cell ratios in G0/ G1 phase were significantly increased,whereas the S phase cell ratios were decreased.In the meantime,western blot showed that the protein expression of TGF-β1 and TβRⅠwere significantly decreased in sh-SPARC group.（all P<0.05）Conclusion Lentiviral vector-mediated SPARC gene silencing inhibits the proliferation and promotes cell apoptosis in keloid fibroblasts,which may be related to the TGF-βsignaling pathway.