Effect Of Partial Obstruction Research Articles

Biomechanical remodelling of obstructed guinea pig jejunum

Data on morphological and biomechanical remodelling are needed to understand the mechanisms behind intestinal obstruction. The effect of partial obstruction on mechanical properties with reference to the zero-stress state and on the histomorphological properties of the guinea pig small intestine was determined in this study. Partial obstruction and sham operation were surgically created in mid-jejunum of guinea pigs. The animals survived 2, 4, 7, and 14 days. The age-matched guinea pigs that were not operated served as normal controls. The segment proximal to the obstruction site was used for histological analysis, no-load state and zero-stress state data, and distension test. The segment for distension was immersed in an organ bath and inflated to 10 cm H 2O. The outer diameter change during the inflation was monitored using a microscope with CCD camera. Circumferential stresses and strains were computed from the diameter, pressure and the zero-stress state data. The opening angle and absolute value of residual strain decreased ( P<0.01 and P<0.001) whereas the wall thickness, wall cross-sectional area, and the wall stiffness increased after 7 days obstruction ( P<0.05, P<0.01). Histologically, the muscle and submucosa layers, especially the circumferential muscle layer increased in thickness after obstruction. The opening angle and residual strain mainly depended on the thickness of the muscle layer whereas the wall stiffness mainly depended on the thickness of the submucosa layer. In conclusion, the histomorphological and biomechanical properties of small intestine (referenced for the first time to the zero-stress state) remodel proximal to the obstruction site in a time-dependent manner.

Effect of partial obstruction on the contraction of guinea pig jejunum

The hypertrophied intestine proximal to an obstruction show abnormal motor function. We compared flow and inflation-induced contractions in the normal, sham-obstructed and partial obstructed guinea pig jejunum. The obstruction was created in animals living for 2, 4, 7 and 14 days with six animals in each group. Six cm jejunal segments proximal to the intervention site were immersed in an organ bath containing 37 °C aerated Krebs solutions at pH 7.4. The intestinal lumen was perfused at 0.8 ml/min. Then, the outlet was closed and ramp distension of 0–7.5 cmH2O was done. The pressure and outer diameter were recorded. Data are shown in Table. In conclusion, partial obstruction time-dependently decreased frequency and amplitude of flow-induced contractions, and increased pressure threshold and maximal amplitude of inflation-induced contractions. The study was supported by Aalborg Hospital.