Figure 1.

Oxidative stress induces actin remodelling, disruption of endothelial layer integrity and increase of endothelial permeability.A) HUVECs were plated in the upper part of a Boyden chamber at a density of 0.6×10⁵ per well and were cultivated for 3 days until the formation of a tight monolayer. Then, FITC-labelled dextran was added (1 mg/ml) together or not with H₂O₂ (250 μM) or histamine (10 μM) for the indicated periods of time. The data represent the permeability changes obtained in a representative experiment and are expressed as the mean fold increase (± SEM) in treated cells relative to untreated cells (n=4 for each conditions). p value was determined by using unpaired Student t test. B) Exponentially growing HUVECs were left untreated (a) or were treated with H₂O₂ (250 μM; b) or histamine (10 μM; c) for 30 minutes. Cells were then fixed, were permeabilized, and were stained for F-actin using Alexa 488-phalloidin. A representative field is shown for each condition. Pictures were captured using a Nikon Eclipse 600 fluorescence microscope (40X).