Mechanism of impaired rheology of aged erythrocytes in relation to the determinants of life span

人红细胞在血流中的寿命主要取决于其通过脾的易滤性和粘附性，进而取决于细胞的变形性。本研究涉及体内老化红细胞的变形性。发展了一种新的灵敏的方法来检测细胞变形性的细微下降，该方法测量了振荡剪切流动中的变形响应。在25℃时，老化红细胞的频率响应在约2赫兹时开始下降，而年轻红细胞的频率响应在3赫兹以上时不变。主要原因被认为是由于细胞内粘度增加所致。长期以来，人们认为老化红细胞的能量代谢降低是通过细胞骨架结构的某些动力学改变而导致变形性的降低，而没有定量的研究。本实验表明，衰老红细胞腺苷、ATP和2，3-DPG的减少不影响细胞的变形性。相反，人为增加的2，3-DPG削弱了变形性，可能是由于细胞内粘度的增加。

The life span of human erythrocytes in blood stream depends mainly on the easiness of their filtrability through spleen and on the adhesivity, thus on the cellular deformability. The present studies concerns with the deformability of the in vivo-aged erythrocytes.1. A novel sensitive method for detecting a subtle decrease in cellular deformability is developed, which measures the deformation response in oscillatory shear flow. The frequency response of the aged erythrocytes begins to decrease at ca. 2 Hz at 25 C, while that of young erythrocytes does not at above 3 Hz. The main cause is suggested to be due to the increased intracellular viscosity.2. The decreased energy metabolism in aged erythrocytes has long been said to cause the decrease of the deformability through some change in the dynamics of cytoskeletal structure, without quantitative studies. The present experiments show that the decrease of adenylates, ATP and 2, 3-DPG found in the aged erythrocytes does not affect the cellular deformability. On contrary, the artificially increased 2, 3-DPG impairs the deformability perhaps due to the increased intracellular viscosity.