Effects of platelet-activating factor on endothelial cell monolayer permeability under hydrostatic perfusion in vitro

摘要

A simple and rapid method was established to study vascular permeability by in vitroperfused endothelial cell monolayers cultured on micropore filter membrane.It can be used todetermine filtration coefficient （Kf） to small molecules and osmotic reflection coefficient （σ） toproteins of the endothelial monolayer.Hanks’ balanced salt solution （HBSS） or 5g/L albuminin HBSS was used to perfuse the confluent endothelial monolayer at the hydrostatic pressure of2.45kPa （25cm H2O）.Control Kf values were 10.1±0.75 and 3.6±0.75μl·min-1·cm-2·kPa（-1）（±,n=3） respectively for the perfusion of HBSS and albumin HBSS,suggesting that al-bumin may decrease endothelial monolayer permeability to water and small molecules.After ex-posure of endothelial monolayer to 10-8mol/L platelet-activating factor （PAF） for 30min,Kfvalues increased to 193.1% and 133.3% respectively.Protein clearance rate (μl.min-1·cm-2)and osmotic reflection coefficient of the control endothelial monolayer were 8.0±3.22 and 0.37±0.09 respectively and those of the PAF treated endothelial monolayer 12.2±2.95μl·min-1·cm-2 and 0.18±0.06,revealing increased permeability to albumin.Computer-assisted imageprocessing demonstrated that PAF treatment decreased cell area while increased cell form factorand intercellular space,suggesting that endothelial cells retracted and rounded,which may bean important mechanism of PAF-induced increase of vascular permeability.