Soutani M, Suzuki Y, Tateishi N, Maeda N
Department of Physiology, School of Medicine, Ehime University, Japan.
Am J Physiol. 1995 May;268(5 Pt 2):H1959-65. doi: 10.1152/ajpheart.1995.268.5.H1959.
Effects of erythrocyte aggregation on the flow dynamics of erythrocytes in microvessels were examined quantitatively by perfusing human erythrocytes suspended in isotonic medium containing various concentrations of dextran (70,400 avg mol wt, Dx-70) into a part of the microvascular bed isolated from rabbit mesentery. Thickness of the marginal cell-free layer was measured with an image analyzer, total flow resistance was determined on the basis of the perfusion pressure-volume flow relationship, and homogeneity of erythrocyte flow was evaluated by the power spectrum obtained by the fast Fourier transform of the light intensity change monitored on single microvessels. With increasing dextran concentration, suspension viscosity of erythrocytes at high shear rates increased linearly and thickness of the cell-free layer increased in a sigmoidal fashion. Flow resistance increased relatively little over the range of dextran concentrations in which the cell-free layer increased most rapidly. Furthermore, the flow pattern of erythrocytes in microvessels became inhomogeneous. In conclusion, the present study shows that Dx-70-induced erythrocyte aggregation results in increased flow resistance in the circulatory system, even through the widening of the cell-free layer tends to reduce the resistance and also results in inhomogeneous flow of erythrocytes in microvessels.
通过将悬浮于含有不同浓度葡聚糖（平均分子量70,400，Dx - 70）的等渗介质中的人红细胞灌注到从兔肠系膜分离出的部分微血管床中，定量研究了红细胞聚集对微血管中红细胞流动动力学的影响。用图像分析仪测量边缘无细胞层的厚度，根据灌注压力 - 体积流量关系确定总流动阻力，并通过对单个微血管上监测的光强度变化进行快速傅里叶变换得到的功率谱来评估红细胞流动的均匀性。随着葡聚糖浓度的增加，高剪切速率下红细胞的悬浮粘度呈线性增加，无细胞层的厚度呈S形增加。在无细胞层增加最快的葡聚糖浓度范围内，流动阻力增加相对较小。此外，微血管中红细胞的流动模式变得不均匀。总之，本研究表明，Dx - 70诱导的红细胞聚集导致循环系统中的流动阻力增加，即使无细胞层的增宽倾向于降低阻力，并且还导致微血管中红细胞的不均匀流动。
