Maksym G N, Fabry B, Butler J P, Navajas D, Tschumperlin D J, Laporte J D, Fredberg J J
School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada.
J Appl Physiol (1985). 2000 Oct;89(4):1619-32. doi: 10.1152/jappl.2000.89.4.1619.
We investigated the rheological properties of living human airway smooth muscle cells in culture and monitored the changes in rheological properties induced by exogenous stimuli. We oscillated small magnetic microbeads bound specifically to integrin receptors and computed the storage modulus (G') and loss modulus (G") from the applied torque and the resulting rotational motion of the beads as determined from their remanent magnetic field. Under baseline conditions, G' increased weakly with frequency, whereas G" was independent of the frequency. The cell was predominantly elastic, with the ratio of G" to G' (defined as eta) being approximately 0. 35 at all frequencies. G' and G" increased together after contractile activation and decreased together after deactivation, whereas eta remained unaltered in each case. Thus elastic and dissipative stresses were coupled during changes in contractile activation. G' and G" decreased with disruption of the actin fibers by cytochalasin D, but eta increased. These results imply that the mechanisms for frictional energy loss and elastic energy storage in the living cell are coupled and reside within the cytoskeleton.
我们研究了培养的活的人气道平滑肌细胞的流变学特性，并监测了外源性刺激引起的流变学特性变化。我们使特异性结合整联蛋白受体的小磁性微珠振荡，并根据施加的扭矩和由珠子剩余磁场确定的珠子旋转运动计算储能模量（G'）和损耗模量（G"）。在基线条件下，G'随频率微弱增加，而G"与频率无关。细胞主要呈弹性，在所有频率下G"与G'的比值（定义为η）约为0.35。收缩激活后G'和G"一起增加，失活后一起降低，而在每种情况下η保持不变。因此，在收缩激活变化期间，弹性应力和耗散应力是耦合的。用细胞松弛素D破坏肌动蛋白纤维后，G'和G"降低，但η增加。这些结果表明，活细胞中摩擦能量损失和弹性能量储存的机制是耦合的，并且存在于细胞骨架内。
