Phasic and tonic stress-strain data obtained in intact intestinal segment in vitro.
Phasic and tonic stress-strain data obtained in intact intestinal segment in vitro.
复制标题
在体外完整肠段中获得的阶段性和强直性应力应变数据。
DOI：
10.1007/s10620-008-0277-z
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发表时间：
2008
影响因子：
3.1
通讯作者：
Gregersen,Hans
中科院分区：
文献类型：
--
作者：
Zhao,Jingbo;Liao,Donghua;Gregersen,Hans
小肠的功能在很大程度上是机械性的，并且它具有通过产生平滑肌层的阶段性（短暂的）和紧张性（持续的）收缩来变形其形状的能力。本研究的目的是获得阶段性和紧张性应力-应变（归一化力-长度）曲线在扩张过程中的离体大鼠空肠和回肠（有点类似的等距长度张力图已知的体外研究的肌肉条）。我们假设，周向应力应变数据取决于纵向拉伸的肠道。从10只Wistar大鼠中分离肠段，并放入含有37°C充气Krebs溶液的器官浴中。在主动和被动肠段上以0、10和20%的纵向拉伸比进行斜坡扩张。在每个纵向拉伸比下，将0至7.5 cmH 2 O的斜坡压力施加于肠腔。通过向溶液中加入钙拮抗剂罂粟碱获得被动条件。根据长度、直径和压力数据以及零应力状态几何形状计算总的和被动的周向应力和应变。主动应力定义为总应力减去被动应力。总的和被动的周向应力作为应变的函数呈指数增加。总应力和被动应力的幅值均以空肠最大。当小肠纵向拉伸时，总周向应力减小，而被动周向应力增大。因此，纵向拉伸导致主动周向应力减小。在纵向拉伸过程中，空肠的被动周向应力比回肠增加更多。因此，主动周向应力在空肠中降低最多。结果表明，空肠和回肠的周向主被动应力和应变取决于纵向拉伸，且存在差异。
The function of the small intestine is to a large degree mechanical, and it has the capability of deforming its shape by generating phasic (short-lasting) and tonic (sustained) contraction of the smooth muscle layers. The aim of this study was to obtain phasic and tonic stress–strain (normalized force–length) curves during distension of isolated rat jejunum and ileum (somewhat similar to the isometric length–tension diagram known from in vitro studies of muscle strips). We hypothesized that the circumferential stress–strain data depend on longitudinal stretch of the intestine. Intestinal segments were isolated from ten Wistar rats and put into an organ bath containing 37°C aerated Krebs solution. Ramp distension was done on active and passive intestinal segments at longitudinal stretch ratios of 0, 10, and 20%. Ramp pressures from 0 to 7.5 cmH2O were applied to the intestinal lumen at each longitudinal stretch ratio. Passive conditions were obtained by adding the calcium antagonist papaverine to the solution. Total and passive circumferential stress and strain were computed from the length, diameter and pressure data and from the zero-stress state geometry. The active stress was defined as the total stress minus the passive stress. The total and passive circumferential stresses increased exponentially as a function of the strain. The amplitude of both the total and passive stress was biggest in the jejunum. The total circumferential stress decreased whereas the passive circumferential stress increased when the intestine was stretched longitudinally. Consequently, longitudinal stretching caused the active circumferential stress to decrease. The passive circumferential stress during longitudinal stretching increased more in the jejunum than in the ileum. Therefore, the active circumferential stress decreased most in the jejunum. In conclusion, the circumferential active-passive stress and strain depend on the longitudinal stretch and differs between the jejunum and ileum.