The aging-delay effects of ginsenoside Rg 1 on hemopoietic stem and progenitor cell are related with changes of cell cycle regulating molecule expression

Objective: to study the aging-delay effect and the potential mechanism of ginsenoside Rg1 in the process of hemopoietic stem cell/hemopoietic progenitor cell sequential transplantation. Method: isolate Sca-1+HSC/HPC from male donor mice. Female recipient mice were divided into four groups after 60Co γ-radiation with fatal dose, control group, aging model group, Rg1 anti-aging group, and Rg1 aging-delay group. We performed the sequential transplantation of Sca-1+HSC/HPC for three generations to construct the in vivo aging mode. Real-time fluorescence quota PCR was used in the detection of the expression of SRY gene in the marrow of the recipients, to ascertain the source of hemocyte, the survival time of the recipients and the hemogram of peripheral blood was observed to confirm the hematopoietic reconstitution and the improvement which was caused by Rg1; CFU-mix, cell cycle analysis and senescence-associated β-galactosidase staining were employed to analysis the biological characters of senescent Sca-1+HSC/HPC cells and the in vivo regulation of Rg1 in this process. Real-time fluorescence quota PCR was used to detect the expression levels of Sca-1+HSC/HPC p16INK4a, p19Arf, p53, p21Cip1/Waf1 mRNA, and western blotting was used to detect the protein levels of Sca-1+HSC/HPC P16INK4a, CDK4, CyclinD, P21Cip1/Waf1, CDK2, CyclinE in recipients. Results: the hemocyte of recipients was from male donors, the 30 d survival rate was dramatically declined after cell sequential transplantation. The hemogram of peripheral blood recovered slowly, and Sca-1+HSC/ HPC of these recipients were arrested in G1 phase, which resulted in the CFU-mix decrease and the positive rate of SA-β-Gal. Every generation in the Rg1 anti-aging group, and Rg1 aging-delay group showed higher 30d survival rate, CFU-mix, WBC, HCT, PLT, and lower rates of cells in G1 phase and SA-β-Gal positive cells than their control in the aging model group. When treated with Rg1, the mRNA level of Sca-1+HSC p16INK4a, p19Arf, p53, p21Cip1/Waf1 and the protein level of P16INK4a, P21Cip1/Waf1, CyclinD1 were down-regulated, the protein level of CDK4, CDK2, CyclinE were up-regulated. These effects were obvious in the Rg1 aging-delay group comparing with the Rg1 anti-aging group. Conclusion: Ginsenoside Rg1 plays an anti-aging role in the process of Sca-1+HSC/HPC sequential transplantation, it has a better effect of aging-delay than anti-aging. The underlying mechanism may relate with its regulation of cell cycle regulating molecule expression.