Low Shear Stress Induces Human Vascular Endothelial Cell Apoptosis by Activating Akt Signal and Increasing Reactive Oxygen Species

Objective: To investigate the effect of low shear stress (LSS) on apoptosis of human vascular endothelial cells (ECs) and explore the possible mechanisms.

Methods: Parallel flow chamber was used to apply LSS at 2 dyne/cm(2) on EA.hy926 cells derived from human umbilical vein endothelial cells for 120 min. Cell apoptosis following LSS was verified by morphological observation, DAPI staining and TUNEL test. The level of intracellular reactive oxygen species (ROS) was measured by dihydroethidium (DHE) and mitoSOX. Western blotting was performed to detect the activity of Akt in the cells.

Results: EC detachment and apoptosis were observed after exposure to 2 dyne/cm(2) LSS for 120 min. Time course study showed that the phosphorylation level of Akt on residues Ser473 and Thr308 was elevated after flow initiation. Exposure to LSS at 2 dyne/cm(2) for 120 min resulted in increased ROS production in the ECs at both the mitochondrial and cytoplasmic levels.

Conclusion: Akt activation and increased ROS levels are involved in LSS-induced EC apoptosis.