[A study on increased permeability and morphological changes in actin cytoskeleton and tight junction of vascular endothelial cells induced by tumor necrosis factor-alpha].

Objective: To study the effect of human tumor necrosis factor-alpha (TNF-alpha) on permeability of human vascular endothelial cell (EA.hy926) monolayer and its mechanism.

Methods: 5, 10, 20 microg/L TNF-alpha was respectively added to the cultured endothelial cell monolayer for 24 hours, or 10 microg/L TNF-alpha for 6, 12, 24 hours. Human vascular endothelial cell (EA.hy926) monolayer permeability was measured by detecting fluorescence intensity of fluorescein isothiocyanate (FITC) labeled dextran. Immunofluorescence and laser confocal microscopy were used to assess vascular endothelial actin cytoskeleton (F-actin) and tight junction protein (ZO-1) distribution. Western blotting was used to assess ZO-1 expression.

Results: Compared with control group, TNF-alpha significantly increased endothelial permeability and induced F-actin redistribution and stress fiber formation with ZO-1 derangement. Gaps increased obviously between endothelial cells. Furthermore, Western blotting showed that TNF-alpha reduced ZO-1 expression in a dose- and time-dependent manner.

Conclusion: TNF-alpha increased endothelial cell permeability by damaging integrity of endothelial barrier function.