血小板激活因子对体外灌注内皮细胞单层通透性的影响

Effects of Platelet-activating Factor on Endothelial Ceil Monolayer Permeability under Hydrostatic Perfusion in Vitro

我们建立了体外灌注内皮细胞单层研究血管通透性的方法,可以测定滤过系数(Kf)以及蛋白质渗透压反射系数(σ)。用Hanks平衡盐液(HBSS)或5 g/L白蛋白HBSS灌注致密内皮单层,Kf值分别是10.1±0.75和3.6±0.75μl·min^(-1)·cm^(-2)·kPa^1(n=3,±s)、说明白蛋白可降低内皮单层对水和小分子物质的通透性。血小板激活因子(PAF)10~8 mol/L作用30 min,用HBSS或白蛋白溶液灌注时Kf值分别增加到193.1％和133.3％。对照组蛋白清除率和σ分别是8.0±3.22μl·min^(-1)·cm^(-2)和0.37±0.09,PAF组分别是12.2±2.95μl·min^(-1)·cm^(-2)和0.18±0.06,相差显著,说明PAF可增加内皮单层的通透性。计算机图像分析表明,PAF作用后内皮细胞面积减小,形状因子、细胞间距增大,提示内皮细胞发生了收缩,这可能是PAF增加血管壁通透性的重要机制。

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 (σ) 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±0.75μl . 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 (μl. 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.