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

Fluid shear stress plays an important role in many physiological and pathophysiological processes of the cardiovascular system. Previous studies have identified the exposure of vascular endothelial cells to fluid mechanical forces can modulate the expression of many genes, including IL-8 gene expression, and IL-8 expression induced by fluid shear stress was time-dependent. To investigate the role of intensity of fluid shear stress on IL-8 expression in human umbilical vein endothelial cells (HUVECs), we had HUVECs exposed to shear stress 2.23, 4.20, 6.08, 8.19, 9.67, 12.15, 14.40, 16.87, and 19.29 dyne/cm2 respectively and employed quantitative reversal transcription-polymerase chain reaction (qRT-PCR) to assay the expression of IL-8 mRNA. The results show that IL-8 mRNA did not express in HUVECs untreated with fluid shear stress. The IL-8 mRNA expression by shear stress was force intensity-dependent. After HUVECs exposed to low fluid shear stress (2.23 dyne/cm2) for 1 h or 2 h, IL-8 mRNA expression increased near 68 or 52 times as that of HUVECs exposed to high fluid shear stress (19.29 dyne/cm2). The linear regression equations between IL-8 mRNA expression (log (copies), y) and shear stress (dyne/cm2, x) are: y = 7.57 - 0.11x, r = 0.97 (for 1 h); y = 7.92 - 0.10x, r = 0.96 (for 2 h). This in vitro study demonstrates the expression of IL-8 gene can be regulated by fluid shear stress. The low shear stress could induces much more expression of IL-8 mRNA, which plays probably an important role in the pathogenesis of inflammation and arteroatherosclerosis.