FIGURE 2.

Persistent DNA damage response and exacerbated cellular senescence in SelH shRNA MRC-5 cells after H₂O₂ treatment. Passage 2 SelH shRNA and scrambled shRNA MRC-5 cells seeded onto coverslips were treated with H₂O₂ (20 μm), followed by a course of 5-day recovery. The percent γH2AX (A) and pATM Ser-1981 (B)-positive cells were presented with mean ± S.E. (n = 6), and representative pictures taken at day 5 after recovery were shown. C, 5 days following the recovery, SA-β-gal-positive cells were determined as described in Fig. 1, and data are presented with mean ± S.E. (n = 6). *, p < 0.05, compared with scrambled shRNA cells; ^#, p < 0.05, compared with 3% O₂.