Effects of White Blood Cells on the Vasculare Resistance in Microvessels

本课题旨在从流体动力学的角度研究白细胞对微血管阻力的影响。首先，使用活体显微镜进行动物实验，观察不同环境下大鼠肠系膜微血管中白细胞的行为。我们观察到红细胞聚集在毛细血管中的白细胞后面，这是由于与红细胞相比，白细胞的速度较慢，毛细血管入口处的白细胞堵塞，以及白细胞在小静脉内皮细胞上滚动和粘连。为了评估白细胞对微血管阻力的影响，我们对微血管中白细胞周围的血流进行了数值分析。结果表明，毛细血管中白细胞后的红细胞聚集可显著提高毛细血管的阻力，这与器官整体灌流实验相一致。发现白细胞与小静脉内皮细胞的黏附增加了微血管阻力，这取决于细胞的数量和血管的直径。对于较小的小静脉，这种增加更为显著

This project is aimed to study the effects of white blood cells on the vascular resistance in microvessels, from a fluid-dynamical point of view. Firstly, animal experiments were performed using an intravital microscopy to observe the behavior of white blood cells in microvessels of the mesentery of rats, under various circumstances. We observed accumulation of red blood cells behind a white blood cell in capillaries, due to the lower velocity of the white blood cell compared to the red blood cells, plugging of white blood cells at the entrance of capillaries, and rolling and adherence of white blood cells onto the endothelium of venules. To evaluate the effect of white blood cells on the microvascular resistance, we numerically analyzed the blood flow around white blood cells in microvessels. It was shown that accumulation of red blood cells behind a white blood cell in capillaries elevates the resistance of the capillary to a significant degree, in agreement with the whole organ perfusion experiments. Adhesion of white blood cells to the endothelium of venules was found to increase the microvascular resistance, depending on the number of cells, and vessel diameter. The increase is more significant for smaller venules