Effects of Platelet-activating Factor on Endothelial Ceil Monolayer Permeability under Hydrostatic Perfusion in Vitro / 第二军医大学学报

ABSTRACT

We established a method to study vascular permeability in vitro on perfused endothelial cell monolayer cultured on micropore filter membrane. It can be used to determine filtration coefficient (Kf) and osmotic reflection coefficient (?) to proteins. Hanks balanced salt solution (HBSS) or 5 g/L albumin in HBSS was used to perfuse confluent endothelial monolayer. Control Kf values were 10.1 ?0.75 and 3.6?0.75?l . min-1 . cm-2 . kPa-1 (n = 3, x?sx) respectively for HBSS and albumin HBSS perfusion, suggesting that albumin may decrease endothelial monolayer permeability to water and small molecules. After exposure of endothelial monolayer to 10-8 mol/L platelet-activating factor (PAF) for 30 min, Kf values increased to 193.1% and 133.3% respectively for HBSS and albumin HBSS perfusion. Protein clearance rate (?l. min-1 . cm-2) and osmotic reflection coefficient of control endothelial monolayer were 8.0?3.22 and 0. 37?0.09 respectively. In PAF treated endothelial monolayer,they were 12.2 ? 2.95ul min-1 cm 2 and 0.18?0.06, revealing increased permeability to albumin. Computer-assisted image processing demonstrated that PAF treatment decreased cell area while increased cell form factor and intercellular space. The results sug-gest that endothelial cells retracted, rounded and it may be an important mechanism in PAF-induced increased vascular permeability.