Research Paper Volume 10, Issue 7 pp 1722—1744

Heme oxygenase-1 ameliorates oxidative stress-induced endothelial senescence via regulating endothelial nitric oxide synthase activation and coupling

Figure 3. HO-1 advanced endothelial NO production to resist senescence in HUVECs. (A) HO-1 inducer Hemin reversed the reduction of the relative fluorescence intensity of DAF-FM indicated endothelial NO production stimulated by H2O2 (200 × magnification). The fluorescence intensity of DAF-FM was normalized to the cell numbers by normalizing to DAPI fluorescence (not shown). *P < 0.05 vs. Control; and #P < 0.05 vs. H2O2. n = 5. (B) Silencing of HO-1 decreased the relative fluorescence intensity of DAF-FM indicated endothelial NO production (200 × magnification). The fluorescence intensity of DAF-FM was normalized to the cell numbers by normalizing to DAPI fluorescence (not shown). *P < 0.05 vs. Control or NC-siRNA. n = 5. (C) NO production was measured according to Griess assay. Hemin reversed the reduction of endothelial NO production stimulated by H2O2, while the protective effect was abolished by ZnPP or L-NAME. *P < 0.05 vs. Control; #P < 0.05 vs. H2O2; $P < 0.05 vs. H2O2+Hemin. n = 5. (D) SA-β-galactosidase staining results showed that ZnPP or L-NAME abolished the anti-senescence effect of Hemin (200 × magnification). *P < 0.05 vs. Control; #P < 0.05 vs. H2O2; $P < 0.05 vs. H2O2+Hemin. n = 5.