Figure 9. Nicotinamide mononucleotide (NMN)treatment preserves NAD+ and prevents senescence in mouse retinal pigment epithelial cells. Primary RPE cells were isolated from 17 days old mouse pups and cultured as described in materials and methods. Mouse primary RPE cells were treated with different doses of FK866 for 5 days to evaluate changes in cell viability, NAD+ content, senescence and SIRT1 expression. (A) Cell viability was evaluated by MTT assay. (B and D) NAD+ content was measured using a NAD assay kit. (C, E and F) RPE senescence were evaluated by and β-galactosidase staining. (G) Changes in expression of SIRT-1 protein levels were evaluated by western blotting. A representative western blot image from three replicates is shown. Data are presented as mean ± S.E.M for n=3 independent experiments. *p<0.05 compared to CON (Vehicle treated) and #p<0.05 compared to FK866.