Abstract: Objective: To investigate the molecular mechanism underlying the protective effect of Solanum tuberosum anthocyanin (STA) on radiation-induced hematopoietic stem/progenitor cell senescence. Methods: C57BL/6 mice were randomly divided into three groups: control, model, STA treatment and STA prevention, and the cell senescence model was constructed by X-ray irradiation. The hemogram of mice in each group were examined using a hematology analyzer after drug administration. Stem cell antigen 1 positive hematopoietic stem/progenitor cells (Sca-1+HSC/HPCs) were isolated and purified from each group by immunomagnetic cell sorting and were stained using a senescence-associated β-galactosidase (SA-β-Gal) kit to calculate the proportion of SA-β-Gal positive cells. The number of mixed lineage colony forming unit (CFU-Mix) was used to evaluate the colony-forming capacity and differentiation potential of hematopoietic stem/progenitor cells. Cell cycle was analyzed by flow cytometry. The mRNA and protein expression of p53 and p21Waf1/Cip1 were detected by quantitative real-time polymerase chain reaction (qPCR) and Western blot. Results: The numbers of red blood cells (RBCs), white blood cells (WBCs) and platelets in the peripheral blood were significantly lower in the model group than in the control group (P < 0.01). In addition, compared with the control group, the proportion of SA-β-Gal positive cells significantly increased (P < 0.01), the number of CFU-Mix significantly fell (P < 0.01), the proportion of G0/G1 phase cells significantly increased, the proportions of G2/M and S phase cells significantly dropped (P < 0.01), and the relative mRNA and protein expression levels of p53 and p21Waf1/Cip1 significantly increased in the model group (P < 0.01). STA could significantly restore the above parameters of mice in the model group irrespective of whether it was administered before or after X-ray radiation, with more pronounced effect being observed in the former case. Conclusion: STA can protect hematopoietic stem/progenitor cells against radiation by regulating the p53-p21Waf1/Cip1 pathway.

Key words: Solanum tuberosum anthocyanin; p53-p21Walf1/Cip1 pathway; radiation; hematopoietic stem/progenitor cell; senescence