Abstract: Objective To investigate the effect of SIRT6 on delaying hematopoietic stem cell and progenitor cell senescence with ginsenoside Rg1. Methods HSC/HPC aged model in vitro was established by t-BHP to induce Sca-1+ HSC/HPC senescence. HSC/HPC aged model in vivo was established as well through the Sca-1+HSC/HPC serial transplantation. The effect of Rg1 to delay Sca-1+HSC/HPC senencence in vitro as well as in vivo were evaluated by senescence-associated β-galactosidase (SA-β-gal) staining, mixed hematopoietic progenitor cell culture(CFU-Mix) and cell cycle assay. The expressions of SIRT6 mRNA and protein were detected by quantitative PCR and Western blotting. Results Compared with aged model in vitro and in vivo, the number of cells entered G0/G1 phase and the percentage of SA-β-gal positive cells were decreased, the number of CFU-Mix was increased in Rg1 treated group and Rg1 prevented group. The expression of SIRT6 mRNA and protein were up regulated in Rg1 treated group and Rg1 prevented group, compared with aged model. The changes of Rg1 prevented group was significantly higher than Rg1 treated group. Conclusion Rg1 could delay Sca-1+HSC/HPC senescence in vitro and in vivo via regulating the expression of SIRT6.

Key words: SIRT6, Sca-1+ HSC/HPC, senescence, ginsenoside Rg1