Ellis C G, Tyml K, Strang B K
Department of Medical Biophysics, University of Western Ontario, London, Canada.
Adv Exp Med Biol. 1989;248:543-50. doi: 10.1007/978-1-4684-5643-1_60.
We have used an analysis of the velocity of individual red cells as the cells pass through a capillary in order to estimate the variability in cross-sectional area of the capillary lumen available for flow along the length of the vessel. The purpose of the study was to determine if there were irregularities of sufficient magnitude and frequency to support Secomb's hypothesis that local constrictions in the capillary lumen could hinder blood flow at low driving pressure, due to the energy required to deform red cells as they pass through the constriction. All capillary segments analyzed to date, in both rat and frog, have shown regions where the velocity of individual cells is consistently faster or slower than that of the mean velocity of all other cells in the same segment. There are approximately two constrictions per 100 microns in the rat and one per 100 microns in the frog. On average these constrictions appear to reduce the cross-sectional area by 30% in the rat and 16% in the frog. These results provide evidence in support of Secomb's hypothesis. In addition, our results from one bifurcation indicate that the capillary lumen increases in cross-sectional area as one moves from the parent vessel to the region of the bifurcation. Downstream of the bifurcation the lumen rapidly decreases in area by 45 to 54%. Thus a red cell must undergo even greater deformation as it passes through a capillary bifurcation than it will in most other sections of the capillary network.(ABSTRACT TRUNCATED AT 250 WORDS)
我们通过分析单个红细胞在穿过毛细血管时的速度，来估计沿血管长度方向上可用于血流的毛细血管腔横截面积的变异性。本研究的目的是确定是否存在足够大的幅度和频率的不规则性，以支持塞科姆的假设，即毛细血管腔内的局部收缩在低驱动压力下会阻碍血流，因为红细胞在通过收缩处时需要能量来变形。迄今为止，在大鼠和青蛙中分析的所有毛细血管段都显示出这样的区域，即单个细胞的速度始终快于或慢于同一段中所有其他细胞的平均速度。大鼠每100微米约有两个收缩处，青蛙每100微米约有一个。平均而言，这些收缩处似乎使大鼠的横截面积减少30%，青蛙减少16%。这些结果为支持塞科姆的假设提供了证据。此外，我们从一个分支处得到的结果表明，从母血管向分支区域移动时，毛细血管腔的横截面积会增加。在分支下游，管腔面积迅速减少45%至54%。因此，红细胞在通过毛细血管分支时必须比在毛细血管网络的大多数其他部分经历更大的变形。（摘要截短至250字）
