Warnke K C, Skalak T C
Department of Biomedical Engineering, University of Virginia, Charlottesville 22908.
Microvasc Res. 1990 Jul;40(1):118-36. doi: 10.1016/0026-2862(90)90012-g.
A model of blood flow in a skeletal muscle microvascular network, typical of a rat spinotrapezius muscle, was used to analyze the effects of white blood cells (WBCs) on network resistance and on the pathways followed by WBCs as they transit the network. This model incorporated plugging of vessel entrances by WBCs and the effects of vessel hematocrit, shear rate, and WBCs on blood apparent viscosity. Blood flow and HCT in each vessel and WBC positions were computed at discrete time steps. WBC introduction increased the network resistance 2.98% under normal conditions, and 14.4% above that of plasma alone when WBCs were considered to be suspended in plasma. This resistance increase was predominantly due to WBC plugging at vessel entrances. Comparison of resistance increases to the number of WBC plugs showed an exponential relationship once a threshold value of plugging was reached. Increased WBC plugging resulted from increases in either the feeding concentration of WBCs or the duration of individual plugs. Increased plug duration was the direct result of using alternate WBC deformation models and increasing WBC viscosity. A WBC viscosity range of 45 to 2400 P was used in the model, corresponding to the viscosities reported by various in vivo and in vitro studies. WBC plugging also significantly affected the pathways taken by WBCs. Under normal conditions, WBCs tended to flow through preferred pathways in the distal portions of the network. With increased plugging, WBC flow became more homogeneous. For significant increases in the network resistance to occur, it is essential that the WBC pathways be distributed throughout the network.
采用一种典型的大鼠斜方肌骨骼肌微血管网络中的血流模型，来分析白细胞（WBC）对网络阻力以及WBC在通过该网络时所遵循路径的影响。该模型纳入了白细胞对血管入口的堵塞以及血管血细胞比容、剪切速率和白细胞对血液表观粘度的影响。在离散的时间步长上计算每个血管中的血流、血细胞比容以及白细胞的位置。在正常条件下，引入白细胞使网络阻力增加2.98%，当认为白细胞悬浮于血浆中时，其阻力比仅血浆时增加了14.4%。这种阻力增加主要是由于白细胞在血管入口处的堵塞。将阻力增加与白细胞堵塞数量进行比较，结果显示一旦达到堵塞阈值，二者呈指数关系。白细胞堵塞增加是由于白细胞输入浓度增加或单个堵塞持续时间增加所致。堵塞持续时间增加是使用不同白细胞变形模型并提高白细胞粘度的直接结果。模型中使用的白细胞粘度范围为45至2400泊，与各种体内和体外研究报告的粘度相对应。白细胞堵塞还显著影响白细胞所采用的路径。在正常条件下，白细胞倾向于流经网络远端部分的优选路径。随着堵塞增加，白细胞流动变得更加均匀。要使网络阻力显著增加，白细胞路径必须分布于整个网络。
