Bates Jason H T, Lauzon Anne-Marie
University of Vermont College of Medicine, Burlington, VT 05405-0075, USA.
J Appl Physiol (1985). 2007 May;102(5):1912-20. doi: 10.1152/japplphysiol.00980.2006. Epub 2007 Jan 4.
We do not yet have a good quantitative understanding of how the force-velocity properties of airway smooth muscle interact with the opposing loads of parenchymal tethering and airway wall stiffness to produce the dynamics of bronchoconstriction. We therefore developed a two-dimensional computational model of a dynamically narrowing airway embedded in uniformly elastic lung parenchyma and compared the predictions of the model to published measurements of airway resistance made in rats and rabbits during the development of bronchoconstriction following a bolus injection of methacholine. The model accurately reproduced the experimental time-courses of airway resistance as a function of both lung inflation pressure and tidal volume. The model also showed that the stiffness of the airway wall is similar in rats and rabbits, and significantly greater than that of the lung parenchyma. Our results indicate that the main features of the dynamical nature of bronchoconstriction in vivo can be understood in terms of the classic Hill force-velocity relationship operating against elastic loads provided by the surrounding lung parenchyma and an airway wall that is stiffer than the parenchyma.
我们尚未很好地定量理解气道平滑肌的力-速度特性如何与实质组织束缚和气道壁硬度的相反负荷相互作用，以产生支气管收缩的动力学。因此，我们开发了一个二维计算模型，该模型模拟了嵌入均匀弹性肺实质中的动态变窄气道，并将模型预测结果与在大鼠和兔子身上进行的已发表测量结果进行比较，这些测量是关于在注射大剂量乙酰甲胆碱后支气管收缩过程中的气道阻力。该模型准确地再现了气道阻力随肺膨胀压力和潮气量变化的实验时间进程。该模型还表明，大鼠和兔子的气道壁硬度相似，且显著大于肺实质的硬度。我们的结果表明，体内支气管收缩动力学的主要特征可以根据经典的希尔力-速度关系来理解，该关系作用于由周围肺实质和比实质更硬的气道壁提供的弹性负荷。
