ABSTRACT
Objective To investigate the effect of hypoxia on the proliferation of nucleus pulposus-derived mesen-chymal stem cells ( NPMSCs) in vitro and explore its possible mechanism .Methods NPMSCs were isolated from nucleus pulposus of Sprague-Dawley rats.Cellular morphology was observed and expression of CD 11b, CD45, CD73, CD90 and CD105 was detected using flow cytometry .The third generation NPMSCs were cultured under nor-moxia (20%O2) and hypoxia (2%O2) for 14 days.Cell viability was determined by the annexin-V-FITC/propidi-um iodide doublestaining assay and cell proliferation was measured by MTT assay .The expressions of hypoxia-in-ducible factor-1α( HIF-1α) , glucose transporter 1( GLUT-1) , vascular endothelial growth factor ( VEGF) , silent information regulator protein 1( SIRT1) and silent information regulator protein 6 ( SIRT6) at the mRNA level were examined by semi-quantitative reverse transcription polymerase chain reaction ( RT-qPCR ).Results NPMSCs formed sunflower-like colony and the third passage NPMSCs became homogeneous and exhibited spindle -like mor-phology .Meanwhile , high expression level of stem cell-related positive antigen molecules and low expression levels of negative antigen molecules .Hypoxia promoted proliferation of NPMSCs and promoted gene expression of HIF-1α, GLUT-1, VEGF, SIRT1 and SIRT6 significantly(P<0.05).Conclusions Hypoxia has a significant impact on the proliferation of NPMSCs and SIRT 1, SIRT6 mediated HIF-1αpathway is potentially involved in the mechanism .