Fig. 4

SIRT1 and Nrf2 mediate the protective effects of STA on H/R exposure-induced injury in H9C2 cells. H9c2 cells were exposed to 1 µM SIRT1 inhibitor (EX-527) or transfected with Nrf2 siRNA for 24 h, followed by incubation with STA (50 µM) and H/R for 18 h. EX-527 reversed the increase in cell viability (a) and decreased caspase-3 (b) by STA. Nrf2 siRNA also reversed the increase in cell viability (c), and decrease in caspase-3 (d) by STA. Western blotting was performed to determine protein levels of SIRT1 and Nrf2, and representative immunoblots in H9c2 cells are shown. (e) EX-527 decreased nrf2 protein in a cell with H/R exposure. (f) The increase in SIRT1 protein by STA remains unchanged by Nrf2 siRNA. Values are expressed as Mean ± SD from at least three independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001 vs. control group; #P < 0.05, ##P < 0.01, ###P < 0.001 vs. STA alone group