Zhao Y, Chien S, Skalak R
Department of Bioengineering, University of California, San Diego, La Jolla 92093, USA.
Biophys J. 1995 Oct;69(4):1309-20. doi: 10.1016/S0006-3495(95)79998-2.
Selectin-mediated leukocyte rolling under flow is an important process in leukocyte recruitment during inflammation. The rolling motion of individual cells has been observed to fluctuate randomly both in vivo and in vitro. This paper presents a stochastic model of the micromechanics of cell rolling and provides an analytical method of treating experimental data. For a homogeneous cell population, the velocity distribution is obtained in an analytical form, which is in good agreement with experimentally determined velocity histograms obtained previously. For a heterogeneous cell population, the model provides a simple, analytical method of separating the contributions of temporal fluctuations and population heterogeneity to the variance of measured rolling velocities. The model also links the mean and variance of rolling velocities to the molecular events underlying the observed cellular motion, allowing characterization of the distribution and release rate of the clusters of molecular bonds that tether the cell to substratum. Applying the model to the analysis of data obtained for neutrophils rolling on an E-selectin-coated surface at a wall shear stress of 1.2 dyn/cm2 yields estimations of the average distance between bond clusters (approximately micron) and the average time duration of a bond cluster resisting the applied fluid force (approximately 0.5 s).
在血流中，选择素介导的白细胞滚动是炎症过程中白细胞募集的一个重要过程。在体内和体外都观察到单个细胞的滚动运动会随机波动。本文提出了一种细胞滚动微观力学的随机模型，并提供了一种处理实验数据的分析方法。对于均匀的细胞群体，以解析形式获得了速度分布，这与先前通过实验确定的速度直方图非常吻合。对于异质细胞群体，该模型提供了一种简单的分析方法，可分离时间波动和群体异质性对测量滚动速度方差的贡献。该模型还将滚动速度的均值和方差与观察到的细胞运动背后的分子事件联系起来，从而能够表征将细胞 tether 到基质的分子键簇的分布和释放速率。将该模型应用于分析在 1.2 dyn/cm2 的壁面剪应力下在 E 选择素包被表面上滚动的中性粒细胞所获得的数据，得出了键簇之间的平均距离（约为微米）和键簇抵抗施加的流体力的平均持续时间（约为 0.5 秒）的估计值。 （注：原文中“tether the cell to substratum”中的“tether”在生物学语境中可理解为“使细胞附着于基质”，这里直接保留英文未翻译，因为不确定是否有更准确的中文术语对应，可根据实际情况调整。）
