Identification of distinct luminal domains for macromolecules, erythrocytes, and leukocytes within mammalian capillaries
Identification of distinct luminal domains for macromolecules, erythrocytes, and leukocytes within mammalian capillaries
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DOI：
10.1161/01.res.79.3.581
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发表时间：
1996-09-01
影响因子：
20.1
通讯作者：
Duling, BR
中科院分区：
文献类型：
--
作者：
Vink, H;Duling, BR
由糖萼和相关血浆蛋白组成的厚内皮表面涂层被认为会减少用于流动血浆大分子和血细胞的功能性毛细血管体积。本研究的目的是比较仓鼠肌毛细血管中大分子、红细胞和白细胞的解剖和功能毛细血管直径。亮场显微镜和荧光显微镜提供了相似的解剖毛细血管直径估计（平均+/-SE）： 5.1+/-0.1 μ m（亮场，10只动物39根毛细血管）和5.1+/-0.2 μ m（膜染料PKH26, 2只动物18根毛细血管）。通过测量红细胞和白细胞的宽度以及全身注射异硫氰酸荧光素-葡聚糖70的毛细血管内分布来估计功能直径。白细胞（5.1+/-0.2 μ m）完全占据解剖毛细血管横截面。相比之下，红细胞（3.9+/-0.2 μ m， 8只动物21根毛细血管）和fitc -葡聚糖（4.3+/-0.2 μ m， 8只动物21根毛细血管）的宽度明显小于解剖毛细血管直径。在毛细腔中连续（1- 5分钟）激发荧光染料（光染料处理）使通过处理部位的红细胞宽度从3.6+/-0.3 μ m增加到4.4+/-0.3 μ m（4只动物的6根毛细血管），使fitc -葡聚糖柱的宽度从4.1+/-0.2增加到4.6+/-0.3 μ m（7只动物的10根毛细血管）。此外，在相同的毛细血管中，与未处理的部位相比，光染料处理使40 μ m长的毛细血管段的毛细血管红细胞压积增加了60%。由此可见，骨骼肌毛细血管壁上有一层0.4 ~ 0.5 μ m厚的内皮表面涂层，这可能代表了血液与毛细血管壁之间真正的活性界面。
A thick endothelial surface coat consisting of the glycocalyx and associated plasma proteins has been hypothesized to reduce functional capillary volume available for flowing plasma macromolecules and blood cells. The purpose of this study was to compare anatomic and functional capillary diameters available for macromolecules, RBCs, and WBCs in hamster cremaster muscle capillaries. Bright-field and fluorescence microscopy provided similar estimates (mean+/-SE) of the anatomic capillary diameter: 5.1+/-0.1 mu m (bright field, 39 capillaries in 10 animals) and 5.1+/-0.2 mu m (membrane dye PKH26, 18 capillaries in 2 animals). Estimates of functional diameters were obtained by measuring the width of RBCs and WBCs and the intracapillary distribution of systemically injected fluorescein isothiocyanate (FITC)-dextran 70. WBCs (5.1+/-0.2 mu m) fully occupied the anatomic capillary cross section. In contrast, the widths of RBCs (3.9+/-0.2 mu m, 21 capillaries in 8 animals) and FITC-dextran (4.3+/-0.2 mu m, 21 capillaries in 8 animals) were significantly smaller than the anatomic capillary diameter. Continuous (1- to 5-minute) excitation of fluorochromes in the capillary lumen (light-dye treatment) increased the width of RBCs passing the treated site from 3.6+/-0.3 to 4.4+/-0.3 mu m (6 capillaries in 4 animals) and the width of the FITC-dextran column from 4.1+/-0.2 to 4.6+/-0.3 mu m (10 capillaries in 7 animals). Furthermore, light-dye treatment increased capillary tube hematocrit by 60% in 40-mu m-long capillary segments compared with untreated sites in the same capillaries. It is concluded that the wall of skeletal muscle capillaries is decorated with a 0.4- to 0.5-mu m-thick endothelial surface coat, which may represent the true active interface between blood and the capillary wall.