Research Paper Volume 11, Issue 11 pp 3505—3522

Nicotinamide phosphoribosyltransferase postpones rat bone marrow mesenchymal stem cell senescence by mediating NAD+–Sirt1 signaling

Figure 2. The specific Nampt inhibitor FK866 induces cellular senescence. (A) Morphological appearance (scale bar = 20 μm) and quantification in young EP MSCs (P3) when treated with FK866. (B) Cell growth curves. (C) Population doubling time (PDT). (D) Evaluation of cell cycle by flow cytometry, and analysis of S-phase fraction (SPF) and proliferation index (PI). (E) Osteogenic differentiation of MSCs determined by Alizarin Red S staining (scale bar = 50 μm). (F) Adipogenic differentiation of MSCs determined by Oil red O staining (Scale bar = 20 μm). (G) SA-β-gal staining of MSCs (scale bar = 50 μm) and quantification. (H) mRNA expression of the senescence marker p16INK4a; n = 3 independent experiments. *P < 0.05, **P < 0.01.