Effects of White Blood Cells on the Vasculare Resistance in Microvessels

本研究从流体动力学的角度探讨白色血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，观察在各种情况下大鼠肠系膜微血管中的白色血细胞的行为。由于白色血细胞的速度低于红细胞，我们观察到红细胞在毛细血管中聚集在白色血细胞后面，白色血细胞在毛细血管入口处堵塞，以及白色血细胞滚动和粘附到微静脉内皮上。为了评估白色血细胞对微血管阻力的影响，我们数值分析了微血管中白色血细胞周围的血流。结果表明，红细胞在毛细血管中的白色血细胞后面的积累显著提高了毛细血管的阻力，这与整个器官灌注实验一致。发现白色血细胞粘附到微静脉内皮上会增加微血管阻力，这取决于细胞数量和血管直径。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