Dartsch P C, Betz E
Physiologisches Institut I, Universität Tübingen, FRG.
Basic Res Cardiol. 1989 May-Jun;84(3):268-81. doi: 10.1007/BF01907974.
Endothelial cells covering the luminal surface of vessels are exposed to at least two different mechanical forces: 1) fluid shear stress produced by the circulation of blood, and 2) periodic stretching and relaxing as a result of the diameter oscillations caused by blood pulsation. In this study we present an apparatus which was constructed to imitate the volume pulse with its typical incisura of the abdominal aorta. Using this apparatus, we exposed cultured endothelial cells to continuously produced cyclic and directional stretching and relaxation for three days. In all experiments cells remained attached and viable when subjected to mechanical stimulation. The vast majority of endothelial cells which underwent mechanical stimulation became elongated and oriented with their longer axis perpendicular to the direction of stretching (angle of cell orientation: alpha = 88.7 degrees +/- 12 degrees; means +/- SD), whereas cells on unstretched membranes had a cobblestone-like appearance and remained in random orientation. In the stretched cells, the factor of elongation was f = 6.8 +/- 1.3; means +/- SD; unstretched cells which exhibited a polygonal shape had a factor of elongation of f = 1.8 +/- 0.8; means +/- SD. In addition, the behavior of cytoskeletal components such as microfilaments and microtubules was examined in the process of cell orientation as both are actively involved in alterations of cell shape and cell migration. Actin filaments were oriented as both are actively involved in alterations of cell shape and cell migration. Actin filaments were oriented in parallel alignment perpendicular to the stretch direction (angle of actin filament orientation: beta = 90.4 degrees +/- 9 degrees; means +/- SD). A distinct orientation of microtubules was not observed, although a noticeable number of microtubules was observed to be in parallel alignment. Furthermore, microtubules of cells which underwent mechanical stimulation exhibited a pronounced asymmetric intracellular distribution with strongly fluorescent cytoplasmic areas in which microtubules seemed to be accumulated. The results indicate that endothelial cell elongation and orientation in vitro can be induced by periodic stretching and relaxation comparable to the periodic oscillations of the vessel wall due to blood pulsation in vivo.
1）血液流动产生的流体剪切应力；2）由于血液搏动引起的直径振荡而导致的周期性拉伸和松弛。在本研究中，我们展示了一种装置，该装置被构建用于模拟腹主动脉具有典型切迹的容积脉搏。使用该装置，我们将培养的内皮细胞暴露于持续产生的周期性定向拉伸和松弛中，持续三天。在所有实验中，细胞在受到机械刺激时仍保持附着且存活。绝大多数受到机械刺激的内皮细胞变得伸长并定向，其长轴垂直于拉伸方向（细胞定向角度：α = 88.7度±12度；平均值±标准差），而未拉伸膜上的细胞具有鹅卵石样外观且保持随机定向。在拉伸的细胞中，伸长因子为f = 6.8±1.3；平均值±标准差；呈现多边形形状的未拉伸细胞的伸长因子为f = 1.8±0.8；平均值±标准差。此外，在细胞定向过程中检查了细胞骨架成分如微丝和微管的行为，因为两者都积极参与细胞形状改变和细胞迁移。肌动蛋白丝被定向，因为两者都积极参与细胞形状改变和细胞迁移。肌动蛋白丝垂直于拉伸方向平行排列（肌动蛋白丝定向角度：β = 90.4度±9度；平均值±标准差）。未观察到微管有明显的定向，尽管观察到大量微管平行排列。此外，受到机械刺激的细胞的微管在细胞内呈现出明显的不对称分布，在强荧光的细胞质区域中微管似乎聚集在其中。结果表明，体外内皮细胞的伸长和定向可由与体内因血液搏动导致的血管壁周期性振荡相当的周期性拉伸和松弛诱导。
