Hoffman Joseph F, Inoué Shinya
Department of Cellular and Molecular Physiology, Yale University, New Haven, CT 06520, USA.
Proc Natl Acad Sci U S A. 2006 Feb 21;103(8):2971-6. doi: 10.1073/pnas.0510884103. Epub 2006 Feb 13.
This paper describes changes that occur in human and Amphiuma red blood cells observed during centrifugation with a special microscope. Dilute suspensions of cells were layered, in a centrifuge chamber, above an osmotically matched dense solution, containing Nycodenz, Ficoll, or Percoll (Pharmacia) that formed a density gradient that allowed the cells to slowly settle to an equilibrium position. Biconcave human red blood cells moved downward at low forces with minimum wobble. The cells oriented vertically when the force field was increased and Hb sedimented as the lower part of each cell became bulged and assumed a "bag-like" shape. The upper centripetal portion of the cell became thinner and remained biconcave. These changes occurred rapidly and were completely reversible upon lowering the centrifugal force. Bag-shaped cells, upon touching red cells in rouleau, immediately reverted to biconcave disks as they flipped onto a stack. Amphiuma red cells displayed a different type of reversible stratification and deformation at high force fields. Here the cells became stretched, with the nucleus now moving centrifugally, the Hb moving centripetally, and the bottom of the cells becoming thinner and clear. Nevertheless, the distribution of the marginal bands at the cells' rim was unchanged. We conclude that centrifugation, per se, while changing a red cell's shape and the distribution of its intracellular constituents, does so in a completely reversible manner. Centrifugation of red cells harboring altered or missing structural elements could provide information on shape determinants that are still unexplained.
本文描述了在使用特殊显微镜进行离心过程中观察到的人类和洞螈红细胞发生的变化。将稀释的细胞悬液在离心室中铺在一种渗透压匹配的浓溶液上方，该浓溶液含有 Nycodenz、Ficoll 或 Percoll（Pharmacia），形成了一个密度梯度，使细胞能够缓慢沉降到平衡位置。双凹形的人类红细胞在低离心力作用下向下移动，摆动最小。当力场增加时，细胞垂直排列，随着每个细胞的下部膨胀并呈现“袋状”形状，血红蛋白沉降。细胞的上部向心部分变薄并保持双凹形。这些变化迅速发生，并且在降低离心力后完全可逆。袋状细胞在接触到叠连中的红细胞时，当它们翻转到细胞叠上时会立即恢复为双凹圆盘状。洞螈红细胞在高力场下表现出不同类型的可逆分层和变形。在这里，细胞被拉长，细胞核现在离心移动，血红蛋白向心移动，细胞底部变薄且清晰。然而，细胞边缘处边缘带的分布没有变化。我们得出结论，离心本身虽然会改变红细胞的形状及其细胞内成分的分布，但这种改变是完全可逆的。对具有改变或缺失结构元件的红细胞进行离心可以提供有关仍未得到解释的形状决定因素的信息。
