[Time-dependent effects of interleukin-8 gene expression in endothelial cells exposed on fluid shear stress]

Fluid shear stress plays an important role in vascular biology. In vivo, endothelial cells are continuously exposed to mechanical shear stress generated by the flowing blood. Previous studies have identified the exposure of vascular endothelial cells to fluid mechanical forces can modulate the expression of many genes involved in vascular physiology and pathophysiology. To investigate the role of fluid shear stress on IL-8 expression in human umbilical vein endothelial cells (HUVECs), we employed quantitative reversal transcription-polymerase chain reaction (qRT-PCR) to assay the expression of IL-8 mRNA. Here we show that IL-8 mRNA did not express in HUVECs untreated with fluid shear stress. IL-8 mRNA expression increased when HUVECs exposed to fluid shear stress for 1 h, and it reached the summit when HUVECs exposed to fluid shear stress for 2 h. Then IL-8 expression gradually decreased at 3 h of stimulation by shear stress and remained at a constant level throughout the time course of the study. The increase of IL-8 expression by shear stress was time-dependent. The biphasic response of IL-8 gene expression was found in experiments in which the applied shear stress was 2.23 dyne/cm2, 4.20 dyne/cm2, or 6.08 dyne/cm2. IL-8 gene expression in response to shear stress was very similar to NF-kappa B in response to shear stress. The induction of IL-8 gene expression by fluid shear stress is probably due to the activation of NF-kappa B. This in vitro study demonstrates the expression of IL-8 gene can be regulated by shear stress. Fluid shear stress induces a biphasic response of human IL-8 gene expression in HUVECs. These considerations suggest that IL-8 expression induced by fluid shear stress in HUVECs may play an important role in the genesis and development of both inflammation and arterioatherosclerosis.