Nagayama Kazuaki, Nagano Yujiro, Sato Masaaki, Matsumoto Takeo
Biomechanics Laboratory, Department of Engineering Physics, Electronics and Mechanics, Nagoya Institute of Technology Omohi College, Japan.
J Biomech. 2006;39(2):293-301. doi: 10.1016/j.jbiomech.2004.11.019.
Tensile properties and actin filament distribution of rat aortic smooth muscle cells (SMCs) were measured in the same cells to correlate the mechanical properties of cells with their cytoskeleton. The cells freshly isolated from rat thoracic aorta with enzymatic dispersion (FSMCs), cultured cells (CSMCs), and CSMCs treated with cytochalasin D to disrupt their actin filaments (CSMCs-CYD) were stretched in a Ca(2+)- Mg(2+) -free Hank's balanced salt solution at 37 degrees C with an originally designed micro tensile tester. Some of CSMCs and CSMCs-CYD were fixed and stained with rhodamine phalloidin for actin filament after the tensile test while they remained attached to the tester. The force-elongation curves were almost linear for all of the three groups. Normalized stiffness E(all) obtained from the slope of the curves was significantly different among groups and was 11.0 +/- 1.9 kPa (mean+/-SEM, n = 8), 2.6 +/- 0.5 kPa (n = 21), 1.5 +/- 0.2 kPa (n = 13), for FSMCs, CSMCs, and CSMCs-CYD, respectively. Relative concentration of the actin filament in the central region of the cell F has significant positive correlation with E(all) both for CSMCs and CSMCs-CYD. The slope of the regression line DeltaE(all)/DeltaF was much higher in the CSMCs than in the CSMCs-CYD. These results indicate that elastic properties of smooth muscle cells may be affected not only by the amount of their actin filaments, but also by their organization and distribution in cells.
在相同的大鼠主动脉平滑肌细胞(SMC)中测量其拉伸特性和肌动蛋白丝分布,以将细胞的力学特性与其细胞骨架相关联。用酶分散法从大鼠胸主动脉新鲜分离的细胞(FSMC)、培养细胞(CSMC)以及用细胞松弛素D处理以破坏其肌动蛋白丝的CSMC(CSMC-CYD),在37℃的无Ca(2+)-Mg(2+)的Hank平衡盐溶液中,使用最初设计的微型拉伸测试仪进行拉伸。在拉伸试验后,一些CSMC和CSMC-CYD在仍附着于测试仪的情况下,用罗丹明鬼笔环肽固定并染色以观察肌动蛋白丝。三组的力-伸长曲线几乎都是线性的。从曲线斜率获得的归一化刚度E(all)在各组之间有显著差异,FSMC、CSMC和CSMC-CYD的E(all)分别为11.0±1.9 kPa(平均值±标准误,n = 8)、2.6±0.5 kPa(n = 21)、1.5±0.2 kPa(n = 13)。对于CSMC和CSMC-CYD,细胞F中央区域肌动蛋白丝的相对浓度与E(all)均有显著正相关。CSMC中回归线的斜率DeltaE(all)/DeltaF比CSMC-CYD中的高得多。这些结果表明,平滑肌细胞的弹性特性可能不仅受其肌动蛋白丝数量的影响,还受其在细胞中的组织和分布的影响。