Akt, but not p38MAPK, serves as the downstream target for NAD(P)H oxidase. (A) Human ECs were preincubated with 1 mM apocynin for 30 minutes. Cells were then stimulated with TNF-α (1 ng/mL) for the time indicated, and phosphorylated and total p38MAPK and Akt were detected by immunoblot (n = 3). (B) After human Ecs were pretreated with vehicle or LY294002 (10 μM) for 0.5 hour, they were treated with TNF-α for 3 hours. Culture media were collected, and CCL2 levels were determined by ELISA (n = 3). #P < 0.05 compared with None. *P < 0.05 compared with vehicle control.