Khismatullin Damir B, Truskey George A
Department of Biomedical Engineering, Duke University, Durham, NC 27708-0281, USA.
Microvasc Res. 2004 Nov;68(3):188-202. doi: 10.1016/j.mvr.2004.07.003.
The effect of channel height on leukocyte adhesion to a lower plate in a parallel-plate flow chamber is studied by direct numerical simulations in three dimensions. The numerical model takes into account deformability and viscoelasticity of the leukocyte, membrane ruffles (microvilli), and the presence of mechanically different regions inside the cell (nucleus and cytoplasm). Leukocyte adhesion is assumed to be mediated by interactions of adhesion molecules on the tips of microvilli with their counterparts on the lower plate. Results of this study indicate that an adherent leukocyte experiences much less drag than a rigid sphere due to its deformation and transient stress growth. While overall leukocyte deformation is modest at shear stresses encountered in the microcirculation, deformation in the contact region is significant. At fixed wall shear stress, the contact area of the cell membrane with the substrate increases with increasing the ratio of cell diameter to channel height, leading to greater adhesion. This suggests that in vitro flow chamber studies typically underestimate leukocyte adhesion that occurs in the microcirculation.
通过三维直接数值模拟研究了通道高度对平行板流动腔中白细胞与下板粘附的影响。数值模型考虑了白细胞的可变形性和粘弹性、膜褶皱（微绒毛）以及细胞内部机械性质不同的区域（细胞核和细胞质）的存在。假定白细胞的粘附是由微绒毛尖端的粘附分子与下板上的对应分子相互作用介导的。本研究结果表明，由于其变形和瞬态应力增长，粘附的白细胞所受阻力比刚性球体小得多。虽然在微循环中遇到的剪切应力下白细胞的整体变形较小，但接触区域的变形很显著。在固定的壁面剪切应力下，细胞膜与基底的接触面积随着细胞直径与通道高度之比的增加而增大，导致更大的粘附。这表明体外流动腔研究通常低估了微循环中发生的白细胞粘附。
