Figure 3.

Oxidative stress inhibits cell proliferation and induces cellular senescence. A: Cell proliferation was assessed by 5-bromo-2′-deoxyuridine (BrdU) assay on day 4 after H₂O₂ treatment. The labeling index of BrdU was counted for at least 1000 cells in each group. The labeling index of BrdU was significantly low in BECs treated with H₂O₂ (112.5 μmol/L, 2 hours), when compared with control BECs. Data are expressed as the mean ± SD. *P < 0.01 compared to control. B: Cellular senescence was assessed by senescence-associated β-galactosidase activity (SA-β-gal) on day 6 after H₂O₂ treatment. Percentage of cells positive for SA-β-Gal activity was significantly higher in BECs treated with H₂O₂ (112.5 μmol/L, 2 hours), when compared with the control BECs. Data are expressed as the mean ± SD. *P < 0.01 compared to the control. C: Cellular senescence was assessed by colony-forming assay on day 6 after H₂O₂ treatment. Number of colonies was significantly lower in BECs treated with H₂O₂ (112.5 μmol/L, 2 hours), when compared with the control BECs. Data are expressed as the mean ± SD. *P < 0.01 compared to the control.