Figure 4.

H₂O₂ treatment inhibits Sirt1 expression and activity. A and B: BNL CL₂ cells were treated with H₂O₂ for 0-24 h at 500 μmol/L. Sirt1 levels determined by Western blot; C and D: BNL CL₂ cells were treated with H₂O₂ at 0-1000 μmol/L for 8 h. Sirt1 levels determined by Western blot; E: Sirt1 deacetylase activity detected by fluorescence spectrophotometry; F: BNL CL₂ cells were treated with H₂O₂ (500 μmol/L) for 4 h, and then SRT1720, a Sirt1 activator, was added into the medium. The supernatants were collected to determinate high mobility group box-1 content by ELISA. All data are presented as the mean ± SD. Statistical analysis was done by the Student’s t-test. ^aP < 0.05 vs 0 group, ^bP < 0.01 vs 0 group or negative control, ^dP < 0.01 vs H₂O₂ group. HMGB1: High mobility group box-1.