Figure 5. Nrf2 protects against apoptosis and senescence under oxidative stress in NPCs. (A, B) Transfection efficiency of lentivirus for Nrf2 overexpression was detected by western blotting. (C) The Annexin V-APC/PI staining analyzed by flow cytometry showed that Nrf2 overexpression reduced the apoptosis rate in TBHP-treated NPCs, which was increased by Nrf2 knockdown. (D) The representative images of SA-β-gal staining of NPCs as treated above and quantification of positive cells; scale bar: 200 μm. (E, F) The western blotting and quantitative protein levels of p16 and C-caspase3 in the NPCs of each treatment group described above. (G) The western blotting and quantitative protein levels of Nrf2 in each human NP tissue group (n = 12, 3 for each grade). (H) Immunohistochemical staining showed that the numbers of Nrf2-positive cells were decreased with IDD; scale bar: 100 μm. All data are expressed as mean ± SD of at least three independent experiments.