Maturation of guinea pig tracheal strip stiffness.
Maturation of guinea pig tracheal strip stiffness.
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成熟的豚鼠气管条僵硬。
DOI：
10.1152/ajplung.00005.2005
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Murphy,ThomasM
中科院分区：
文献类型：
--
作者：
Wang,Lu;Chitano,Pasquale;Murphy,ThomasM
先前，我们发现豚鼠气管条的缩短速度在幼鼠（3周龄）中比在婴儿（1周龄）和成年动物（3-mo龄）中最大。在三个年龄组中，最大的缩短速度与最小的缩短阻力有关。如果气管组织的刚度，一种测量组织对几何变形的反应，在三个年龄组之间是不同的，这还有待验证。我们假设完整气管条的硬度在幼年组是最低的，这可以解释气道平滑肌抵抗缩短和缩短速度的个体发生。通过逐步变形测量的静态刚度没有显示出与年龄相关的差异。组织对振荡变形的响应评估表明，未受刺激的气管条在婴儿、幼年和成人中的动态刚度分别为8.35±0.88、4.15±1.09和8.21±1.57 kPa，相位角分别为10.3±2.93、2.46±0.67和7.87±1.77°。未刺激的幼条在动态刚度和相位角上明显低于未刺激的婴儿或成人条。这种成熟的轮廓与肌条预设长度或振荡模式/振幅无关，但在收缩峰值时被甲氨基酚或电场刺激所消除。这些结果表明，与其他年龄组相比，青少年气管条的非收缩成分硬度较低，含有较少的粘性/摩擦成分。这可能为幼年气道平滑肌对长度变化的抵抗力降低提供了功能基础。
Previously, we showed the shortening velocity of guinea pig tracheal strips was the greatest in juvenile (3-wk-old) compared with infant (1-wk-old) and adult animals (3-mo-old). The greatest shortening velocity was associated with the least resistance to shortening calculated from force-velocity curves among the three age groups. It remained to be verified if the stiffness of tracheal tissue, a measure of tissue response to geometrical deformations, is different among the three age groups. We hypothesized that stiffness of intact tracheal strips is lowest in the juvenile group and that this can explain the ontogeny of airway smooth muscle resistance to shortening and shortening velocity. Static stiffness measured through stepwise deformations showed no age-related differences. Evaluation of tissue response to oscillatory deformations showed that the dynamic stiffness of unstimulated tracheal strips was 8.35 ± 0.88, 4.15 ± 1.09, and 8.21 ± 1.57 kPa, and the phase angle was 10.3 ± 2.93, 2.46 ± 0.67, and 7.87 ± 1.77° in infant, juvenile, and adult, respectively. Unstimulated juvenile strips were significantly lower in dynamic stiffness and phase angle compared with unstimulated infant or adult strips. This maturational profile was independent of muscle strip preset length or oscillation mode/amplitude but was abolished at peak of contraction to either carbachol or electric field stimulation. These results suggest that the noncontractile components of tracheal strips are less stiff and contain fewer viscous/frictional elements in juvenile than in other age groups. This may provide a functional basis for reduced resistance to length changes in juvenile airway smooth muscle.