Spermidine Retarded the Senescence of Multipotent Mesenchymal Stromal Cells In Vitro and In Vivo through SIRT3-Mediated Antioxidation

Figure 2

SPD intervention delayed hUCMSC replicative senescence. (a) The replicative potential of hUCMSCs cocultivated with 0 (control), 1, 10, or 100 μM SPD, respectively, is expressed as the population doubling time (population doubling level vs. time). (b) A representative micrograph including the SA-β-gal staining of hUCMSCs from earlier passages (PDL6), later passages (PDL26), and later passage cells supplemented with 10 μM SPD during subculture (PDL26+SPD). (c) The percentage of senescent cells stained in blue in each group was assessed by quantitative analysis. (d) Immunofluorescence staining of Ki67 foci appeared red, while blue indicated nuclei stained with Hoechst 33342;  μm. (e) Representative western blotting results for the protein expression of SIRT3, p-P53-ser15, P53, OCT4, SOX2, or P21 in different groups. (f) Protein expression levels detected by western blotting were quantified using ImageJ software and normalized to PDL6. (g) Representative western blotting results for the protein expression of SIRT3, p-P53-ser15, P53, or P21 in different groups when SIRT3 was silenced. (h) Protein expression levels detected by western blotting were quantified and normalized to PDL6. Approximately 10⁵ cells per well were seeded in 6-well plates. All quantitative data were obtained from three independent experiments and presented as ; and signify a significant difference between the indicated groups. N.S.: not significant;  μm.

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