Effects of fluid shear stress on apoptosis of cultured human umbilical vein endothelial cells induced by LPS.

The objective of our research was to reveal the effects of shear stress on the apoptosis of cultured human umbilical vein endothelial cells (HUVECs) induced by lipopolysaccharide (LPS). A parallel-plate flow chamber was used to control the strength and duration of shear stress (SS), and apoptosis was measured by immunocytochemistry and radio-immunoassay. Some important conclusions were drawn. In the stationary state, apoptosis of HUVECs could be induced by LPS (50 microg/ml). An SS of 15 dyn/cm(2) could inhibit the apoptosis induced by LPS. However, an SS of 4 dyn/cm(2) had less effect on the same process. At the same time, the experiment demonstrated that the increase in IL-6 secretion by LPS can be inhibited by two different levels of shear stress. Moreover, the inhibition effect was more obvious under high level stress than under low level. We also found that the effect of shear stress on IL-8 was less effective than on IL-6. This research provides data for understanding the mechanism of the contribution of hemodynamic forces to atherosclerosis.