流体切应力对中性粒细胞表面粘附分子表达的影响

Effects of Fluid Shear Stress on Neutrophil Surface Expression of Adhesion Molecules

采用Ｌｏｗ ｓｈｅａｒ ３０ 对中性粒细胞施加不同强度、不同形式的剪切，在经过荧光单克隆抗体标记后，用流式细胞仪检测ＣＤ１８ 和ＣＤ６２Ｌ在细胞表面的表达情况。结果显示：剪切后ＣＤ１８ 有显著升高，而ＣＤ６２Ｌ阳性细胞比率显著下降，但对ＣＤ６２Ｌ阳性细胞表面ＣＤ６２Ｌ的含量没有明显影响。不同方式的剪切影响有细微差异。ｆＭＬＰ或ＴＮＦ单独作用可以使细胞表面的ＣＤ１８ 表达轻微降低而使ＣＤ６２Ｌ同样发生脱落，刺激因子与切应力同时作用下两种粘附分子的表现有加和性。本文提示，力学作用与生物化学因子的激活作用可能是通过不同的感受器，经过不同的信号转导途径，产生不了同的效应；

Fluid shear is a physiological and functional environment for circulating neutrophils where various chemoattractants and cytokines have different effects on neutrophils, activating them or evoking inflammation. So far there have been abundant in vitro researches demonstrating that while neutrophils are activated,some adhesion molecules, which are expressed on the surface of neutrophils, are necessary to cell to cell adhesion, and the quantity or quality of these molecules will be changed. The above results were all obtained under static fluid which is quite different from physiological condition. Recently, we used Low Shear 30 to provide steady or sinusoidal oscillated fluid shear stress on separated neutrophils with or without f MLP/TNF stimulation. FITC anti CD18 monoclonal antibody and PE anti CD62L monoclonal antibody were added to label CD18 and CD62L on neutrophils suface respectively. Flow cytometry was used to quantify surface expression and positive cell percentage of these two adhesion molecules. The results demonstrat that fluid shear stress increases the expression of CD18 significantly and decreases the CD62L positive cell percentage, but it does not influence the CD62L expression on the CD62L positive cells. The effects of the different patterns of fluid shear stress are not much different, f MLP or TNF can slightly decrease the expression of CD18 and make CD62L shedding respectively. When one of the two activators and the fluid shear stress act together, the expression of the two adherent molecules can be added.This indicates that the mechanical and biochemical stiumlative action can produce different effects through different receptors and different signal transduction pathways. So the mechanical environment shold be considered in the research of activation and adhesion of neutrophils.