Laminar flow inhibits 15d-PGJ₂-induced endothelial apoptosis. Confluent HUVECs were cultured under L-flow (12 dyne/cm²) or a static condition for 24 h. Cells were then exposed to 10 µM 15d-PGJ₂ for 8 h. (A) Cell lysates were applied for immunoblotting with anti-PARP, anti-cleaved caspase 3, and anti-tubulin antibodies. Data are representative of results from three separate experiments. (B) Cell viability was determined by using MTT assay. Data are expressed as the mean±SD from three independent experiments. ^*P<0.01. Morphological changes of HUVECs were examined by microscopy under control (C), 15d-PGJ₂ (D), or 15d-PGJ₂ under L-flow (E). Scale bars=100 µm (C-E). 15d-PGJ₂, 15-deoxy-Δ(12,14)-prostaglandin J₂; HUVECs, human umbilical vein endothelial cells; L-flow, steady laminar flow; PARP, poly (ADP-ribose) polymerase; OD, optical density.