Figure 4. HO-1 retarded H2O2-induced HUVEC senescence through eNOS activation via Akt. (A) Expressions of p-eNOS(Ser1177) and total eNOS were measured in HUVECs treated with or without H2O2 and Hemin in the presence or absence of Akt inhibitor MK-2206, PKA inhibitor H-89 or AMPK inhibitor Compound C (CP-C). *P < 0.05 vs. Control; #P < 0.05 vs. H2O2; $P < 0.05 vs. H2O2+Hemin; n.s., non significant. n = 5. (B) Expressions of p-eNOS(Ser1177) and total eNOS were measured in HUVECs infected with or without HO-1 recombinant adenovirus in the presence or absence of Akt inhibitor MK-2206. *P < 0.05 vs. Ad-GFP; #P < 0.05 vs. Ad-GFP+H2O2; $P < 0.05 vs. Ad-HO-1+H2O2; n.s., non significant. n = 5. (C) Expressions of p-eNOS(Ser1177) and total eNOS were measured in HUVECs transfected with or without HO-1 siRNA. *P < 0.05 vs. Control or NC-siRNA; n.s., non significant. n = 5.