Figure 5. BMSCs improved the aging thymus and spleen through targeting P21/PCNA signaling pathway. (A) Protein expression of P16, P21, and PCNA were measured by western blotting; (B) Quantification analysis of protein expression of P16, P21, and PCNA; (C) Quantification analysis of mRNA expression of P16, P21, and PCNA; (D) Influence of BMSCs on P21 and PCNA in the tissues measured by immunohistochemical staining; (E) The proliferative status of the tissues (thymus and spleen) were analyzed by BrdU staining. * P<0.05 compared with the control group; ** P<0.05 compared with the aging model group.