STATIC AND DYNAMIC RIGIDITIES OF NORMAL AND SICKLE ERYTHROCYTES - MAJOR INFLUENCE OF CELL HEMOGLOBIN CONCENTRATION
STATIC AND DYNAMIC RIGIDITIES OF NORMAL AND SICKLE ERYTHROCYTES - MAJOR INFLUENCE OF CELL HEMOGLOBIN CONCENTRATION
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DOI：
10.1172/jci111234
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发表时间：
1984-01-01
影响因子：
15.9
通讯作者：
LEUNG, A
中科院分区：
文献类型：
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作者：
EVANS, E;MOHANDAS, N;LEUNG, A
红细胞的静态和动态变形能力是微循环血流的重要决定因素。为了确定增加的细胞Hb浓度对这些特性的影响，使用单个细胞的微机械操作定量分析了具有确定细胞密度的氧合正常红细胞和镰状红细胞分离亚群的静态和动态变形能力。表征静态变形性能的流变学特性是膜的拉伸刚度和弯曲刚度。为了表征细胞的动态变形能力，我们测量了从拉伸和弯曲变形中快速弹性恢复的时间常数。镰状细胞的拉伸刚度随血红蛋白浓度的增加而增加，而正常细胞的拉伸刚度与细胞水合状态无关。镰状细胞在比正常细胞低得多的Hb浓度下表现出非弹性行为。血红蛋白浓度升高时，正常细胞和镰状细胞的动态刚性增加到相同程度。随着细胞脱水的增加，这种动态刚度的增加比静态刚度的增加明显得多。脱水后的镰状细胞的静态和动态刚度都可以通过水化细胞而大大提高。大体积Hb浓度的增加，可能在膜附近异常增加，可能在调节镰状细胞的刚性中起主要作用。不可逆的膜变化也出现在体内细胞脱水中，导致膜剪切刚度和塑性流动增加。脱水镰状细胞硬度的显著增加可能对其在微血管中的循环动力学有重要影响。
Static and dynamic deformabilities of erythrocytes are important determinants of microcirculatory blood flow. To determine the influence of increased cellular Hb concentration on these properties, static and dynamic deformabilities of isolated subpopulations of oxygenated normal and sickle erythrocytes with defined cell densities were quantitated using micromechanical manipulations of individual cells. The rheological properties measured to characterize static deformability were membrane extensional rigidity and bending rigidity. To characterize dynamic deformability of the cells, we measured the time constants for rapid elastic recovery from extensional and bending deformations. The extensional rigidity of sickle cells increased with increasing cell hemoglobin concentration while that of normal cells was independent of the state of cell hydration. Sickle cells exhibited inelastic behavior at much lower cell Hb concentrations than normal cells. The dynamic rigidity of both normal and sickle cells was increased to the same extent at elevated Hb concentrations. This increase in dynamic rigidity with increasing cellular dehydration was much more pronounced than that seen for static rigidity. Both the increased static and dynamic rigidities of the dehydrated sickle cells could be greatly improved by hydrating the cells. Increased bulk Hb concentration, which is perhaps inordinately increased adjacent to the membrane, may play a major role in regulating the rigidity of sickle cells. Irreversible membrane changes also appear to accompany cell dehydration in vivo, resulting in increased membrane shear rigidity and plastic flow. The marked increases in rigidity of dehydrated sickle cells observed here may have a major influence on the dynamics of their circulation in the microvasculature.