Kuzman D, Svetina S, Waugh R E, Zeks B
Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Lipiceva 2, 1000, Ljubljana, Slovenia.
Eur Biophys J. 2004 Feb;33(1):1-15. doi: 10.1007/s00249-003-0337-4. Epub 2003 Sep 12.
The natural biconcave shape of red blood cells (RBC) may be altered by injury or environmental conditions into a spiculated form (echinocyte). An analysis is presented of the effect of such a transformation on the resistance of RBC to entry into capillary sized cylindrical tubes. The analysis accounts for the elasticity of the membrane skeleton in dilation and shear, and the local and nonlocal resistance of the bilayer to bending, the latter corresponding to different area strains in the two leaflets of the bilayer. The shape transformation is assumed to be driven by the equilibrium area difference (delta A(0), the difference between the equilibrium areas of the bilayer leaflets), which also affects the energy of deformation. The cell shape is approximated by a parametric model. Shape parameters, skeleton shear deformation, and the skeleton density of deformed membrane relative to the skeleton density of undeformed membrane are obtained by minimization of the corresponding thermodynamic potential. Experimentally, delta A(0) is modified and the corresponding discocyte-echinocyte shape transition obtained by high-pressure aspiration into a narrow pipette, and the deformability of the resulting echinocyte is examined by whole cell aspiration into a larger pipette. We conclude that the deformability of the echinocyte can be accounted for by the mechanical behavior of the normal RBC membrane, where the equilibrium area difference delta A(0) is modified.
红细胞（RBC）的天然双凹形可能会因损伤或环境条件而改变为有刺状的形式（棘红细胞）。本文分析了这种转变对红细胞进入毛细血管大小的圆柱形管的阻力的影响。该分析考虑了膜骨架在扩张和剪切中的弹性，以及双层膜对弯曲的局部和非局部阻力，后者对应于双层膜两个小叶中的不同面积应变。形状转变被认为是由平衡面积差（δA(0)，双层膜小叶平衡面积之间的差异）驱动的，这也会影响变形能量。细胞形状由参数模型近似。通过最小化相应的热力学势，获得形状参数、骨架剪切变形以及变形膜的骨架密度相对于未变形膜的骨架密度。实验上，通过向狭窄移液器中进行高压抽吸来改变δA(0)，并获得相应的圆盘状细胞 - 棘红细胞形状转变，然后通过将所得棘红细胞全细胞抽吸到更大的移液器中来检查其变形性。我们得出结论，棘红细胞的变形性可以通过正常红细胞膜的力学行为来解释，其中平衡面积差δA(0)发生了改变。
