Al Jamal R, Roughley P J, Ludwig M S
Meakins Christie Laboratories, Royal Victoria Hospital, McGill University, Montreal, Quebec, Canada.
Am J Physiol Lung Cell Mol Physiol. 2001 Feb;280(2):L306-15. doi: 10.1152/ajplung.2001.280.2.L306.
We tested the hypothesis that matrix glycosaminoglycans contribute to lung tissue viscoelasticity. We exposed lung parenchymal strips to specific degradative enzymes (chondroitinase ABC, heparitinase I, and hyaluronidase) and determined whether the mechanical properties of the tissue were affected. Subpleural parenchymal strips were obtained from Sprague-Dawley rats and suspended in a Krebs-filled organ bath. One end of the strip was attached to a force transducer and the other to a servo-controlled lever arm that effected sinusoidal oscillations. Recordings of tension and length at different amplitudes and frequencies of oscillation were recorded before and after enzyme exposure. Resistance, dynamic elastance, and hysteresivity were estimated by fitting the equation of motion to changes in tension and length. Quasi-static stress-strain curves were also obtained. Exposure to chondroitinase and heparitinase I caused significant increases in hysteresivity, no decrement in resistance, and similar decreases in dynamic elastance relative to control strips exposed to Krebs solution only. Conversely, measures of static elastance were different in treated versus control strips. Hyaluronidase treatment did not alter any of the mechanical measures. These data demonstrate that digestion of chondroitin sulfate and heparan sulfate alters the mechanical behavior of lung parenchymal tissues.
我们验证了基质糖胺聚糖有助于肺组织粘弹性的这一假设。我们将肺实质条带暴露于特定的降解酶（软骨素酶ABC、硫酸乙酰肝素酶I和透明质酸酶）中，并确定组织的力学性能是否受到影响。从Sprague-Dawley大鼠获取胸膜下实质条带，并将其悬浮于充满Krebs液的器官浴槽中。条带的一端连接到力传感器，另一端连接到实现正弦振荡的伺服控制杠杆臂。在酶暴露前后记录不同振荡幅度和频率下的张力和长度记录。通过将运动方程拟合到张力和长度的变化来估计阻力、动态弹性和滞后性。还获得了准静态应力-应变曲线。与仅暴露于Krebs溶液的对照条带相比，暴露于软骨素酶和硫酸乙酰肝素酶I导致滞后性显著增加，阻力没有降低，动态弹性有类似程度的降低。相反，处理过的条带与对照条带的静态弹性测量结果不同。透明质酸酶处理未改变任何力学指标。这些数据表明硫酸软骨素和硫酸乙酰肝素的消化改变了肺实质组织的力学行为。
