Ebrahimzadeh P R, Högfors C, Braide M
Department of Anatomy and Cell Biology, Göteborg University, Sweden.
J Leukoc Biol. 2000 May;67(5):651-61. doi: 10.1002/jlb.67.5.651.
In this study the fluid gradient chamber, a modified version of the Boyden chamber that enables mobile gradients, was used to study the migration of human granulocytes in gradients of fMLP. Temporal chemotactic gradients were created by moving density-stabilized spatial gradients at different velocities in relation to migrating cells. Random and directed cell migration was quantified by applying a theoretical population distribution model to experimental cell distributions obtained from cell counts at different depths in the filters. Rates of random and directed migration generally increased with gradient velocity. At negative gradient velocities, i.e., when the gradients were moved in a direction opposite to that of cell migration to decrease fMLP concentration over time, random and directed migration was inhibited. At positive gradient velocities, migration rates were not significantly different from those seen in immobile gradients. The fact that the rate of directed migration was smaller at negative gradient velocities indicates that negative temporal gradients reduced the average speed and/or orientation of the chemotactically migrating cells. In immobile gradients, the cells generated a small concentration increase over time when they migrated in the up-gradient direction. Consequently, a positive temporal gradient as perceived by the cells may act as a positive feedback signal to maintain chemotactic migration.
在本研究中，使用了流体梯度室，它是博伊登室的改良版本，能够形成移动梯度，用于研究人粒细胞在fMLP梯度中的迁移。通过以相对于迁移细胞的不同速度移动密度稳定的空间梯度来创建时间趋化梯度。通过将理论群体分布模型应用于从滤膜不同深度的细胞计数获得的实验细胞分布，对随机和定向细胞迁移进行量化。随机和定向迁移速率通常随梯度速度增加。在负梯度速度下，即当梯度朝着与细胞迁移相反的方向移动以随时间降低fMLP浓度时，随机和定向迁移受到抑制。在正梯度速度下，迁移速率与固定梯度中观察到的速率没有显著差异。负梯度速度下定向迁移速率较小这一事实表明，负时间梯度降低了趋化迁移细胞的平均速度和/或方向。在固定梯度中，细胞向上梯度方向迁移时，随着时间推移会产生少量浓度增加。因此，细胞所感知到的正时间梯度可能作为一种正反馈信号来维持趋化迁移。
