Core Facility Laboratory Animal Breeding and Husbandry, Decentralized Biomedical Facilities, Medical University Vienna, Austria.
Division of Anatomy, Center for Anatomy and Cell Biology, Medical University Vienna, Austria.
Clin Hemorheol Microcirc. 2023;84(4):369-383. doi: 10.3233/CH-231701.
Yielding and shear elasticity of blood are merely discussed within the context of hematocrit and erythrocyte aggregation. However, plasma might play a substantial role due its own viscoelasticity.
If only erythrocyte aggregation and hematocrit would determine yielding, blood of different species with comparable values would present comparable yield stresses.
rheometry (SAOS: amplitude and frequency sweep tests; flow curves) of hematocrit-matched samples at 37°C. Brillouin Light Scattering Spectroscopy at 38°C.
Yield stress for pig: 20mPa, rat: 18mPa, and human blood: 9mPa. Cow and sheep blood were not in quasi-stationary state supporting the role of erythrocyte aggregation for the development of elasticity and yielding. However, pig and human erythrocytes feature similar aggregability, but yield stress of porcine blood was double. Murine and ruminant erythrocytes both rarely aggregate, but their blood behavior was fundamentally different. Pig plasma was shear-thinning and murine plasma was platelet-enriched, supporting the role of plasma for triggering collective effects and gel-like properties.
Blood behavior near zero shear flow is not based solely on erythrocyte aggregation and hematocrit, but includes the hydrodynamic interaction with plasma. The shear stress required to break down elasticity is not the critical shear stress for dispersing erythrocyte aggregates, but the shear stress required to fracture the entire assembly of blood cells within their intimate embedding.
血液的屈服和剪切弹性仅在血细胞比容和红细胞聚集的背景下讨论。然而，由于其自身的粘弹性，血浆可能会起到重要作用。
如果仅仅是红细胞聚集和血细胞比容决定屈服，那么具有可比值的不同物种的血液应该表现出可比的屈服应力。
在 37°C 下对匹配血细胞比容的样本进行流变学（SAOS：幅度和频率扫描测试；流动曲线）测量。在 38°C 下进行布里渊光散射光谱测量。
猪的屈服应力为 20mPa，大鼠为 18mPa，人类血液为 9mPa。牛和绵羊的血液不在准静态状态，这支持了红细胞聚集对于弹性和屈服发展的作用。然而，猪和人类的红细胞具有相似的聚集能力，但猪血液的屈服应力却是人类的两倍。鼠类和反刍动物的红细胞都很少聚集，但它们的血液行为却有根本的不同。猪血浆具有剪切变稀的特性，而鼠血浆富含血小板，这支持了血浆在引发集体效应和凝胶状特性方面的作用。
接近零剪切流动的血液行为不仅仅取决于红细胞聚集和血细胞比容，还包括与血浆的水动力相互作用。打破弹性所需的剪切应力不是分散红细胞聚集所需的临界剪切应力，而是打破整个血细胞紧密嵌入的组装所需的剪切应力。
