Mechanical anisotropy of rat aortic smooth muscle cells decreases with their contraction - (Possible effect of actin filament orientation)
Mechanical anisotropy of rat aortic smooth muscle cells decreases with their contraction - (Possible effect of actin filament orientation)
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DOI：
10.1299/jsmec.47.985
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发表时间：
2004-12-01
期刊：
影响因子：
--
通讯作者：
Matsumoto, T
中科院分区：
文献类型：
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作者：
Nagayama, K;Matsumoto, T
用自制的微拉伸仪测定了刚分离的大鼠胸主动脉平滑肌细胞在主、小轴上的拉伸性能。在未处理的细胞和用10(-5)M血清素诱导收缩的细胞中，获得了施加于细胞的张力与其伸长之间的关系。未经处理的FSMCs的初始刚度，通过垂直于拉伸方向的初始横截面积标准化，在长轴（14.8 +/- 4.3 kPa，平均SEM， n = 5）明显高于短轴（2.8 +/- 1.0 kPa, n = 5）。在收缩作用下，小轴刚度（59.0 +/- 9.4 kPa, n = 4）明显高于大轴刚度（88.1 +/- 13.3 kPa, n = 4）。在收缩状态下，这两个方向的差异是微不足道的。用激光共聚焦显微镜观察未经处理的FSMCs中肌动蛋白丝的形态，发现它们是几乎平行于长轴的长纤维，而收缩细胞中的肌动蛋白丝则呈聚集结构，没有优先方向。这些结果可能表明，未经处理的FSMCs的各向异性是由其肌动蛋白丝的各向异性排列引起的，而这种各向异性在收缩引起的肌动蛋白丝重组后消失。
Tensile properties of smooth muscle cells freshly isolated from rat thoracic aortas (FSMCs) in their major and minor axes were measured using a laboratory-made micro tensile tester. The relationship between the tension applied to a cell and its elongation was obtained in untreated cells and those treated with 10(-5) M serotonin to induce contraction. An initial stiffness of untreated FSMCs, normalized by their initial cross-sectional area perpendicular to the stretch direction, was significantly higher in the major axis (14.8 +/- 4.3 kPa, mean SEM, n = 5) than the minor axis (2.8 +/- 1.0 kPa, n = 5). The stiffness increased significantly in response to the contraction, but the increase was much higher in the minor axis (59.0 +/- 9.4 kPa, n = 4) than in the major (88.1 +/- 13.3 kPa, n = 4). The difference between the two directions was insignificant in the contracted state. Observations of the morphology of actin filaments with a confocal laser scanning microscope in untreated FSMCs revealed that they were long fibers running almost parallel to the major axis, while those in contracted cells showed an aggregated structure without a preferential direction. These results may indicate that anisotropy in untreated FSMCs is caused by the anisotropic alignment of their actin filaments, and that such anisotropy disappears in response to actin filament reorganization caused by the contraction.