Protective Effect of Solanum tuberosum Anthocyanin against Radiation-Induced Hematopoietic Stem/Progenitor Cell Senescence via the p53-p21^Waf1/Cip1 Pathway

To investigate the molecular mechanism underlying the protective effect of Solanum tuberosum anthocyanin (STA) on radiation-induced hematopoietic stem/progenitor cell senescence.

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 p21^Waf1/Cip1 were detected by quantitative real-time polymerase chain reaction (qPCR) and Western blot.

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 p21^Waf1/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.

STA can protect hematopoietic stem/progenitor cells against radiation by regulating the p53-p21^Waf1/Cip1 pathway.