Compliance changes of the gastrointestinal tract in streptozotocin-induced diabetic rats

In order to elucidate diabetic gastrointestinal disorders, we measured the length, diameter, volume, and intraluminal pressure of the isolated segments of the duodenum, jejunum, ileum, and proximal colon during injection of Tyrode's solution into them, as well as wet weight. Wet weight of the stomach and of each intestinal segment of 3 cm length were similar between normal and diabetic preparations, except the duodenum. Wet weight of the diabetic duodenum was significantly heavier than that of normal. However, capacity of all diabetic gastrointestinal segments was significantly larger than that of normal ones, even after corrected for wet weight (ml/g wet weight). During saline injection, normal intestinal segments were more easily distended longitudinally than circumferentially. Contrarily, diabetic ones were distended more circumferentially than normal, as well as longitudinally. Pressure-volume relationships showed that pressure inside of the diabetic gastrointestinal tract increased much more moderately than that of normal one according to volume increase during saline injection. Similarly, tension inside of diabetic intestinal segments increased much more moderately than that of normal ones. Chord and slope compliance of diabetic gastrointestinal tract was generally larger than those of normal one. Histologically, there are no remarkable differences in cross-sectional area between normal and diabetic intestinal segments after usual fixation without intraluminal fixative injection. However, diabetic segments were much more remarkably dilated than normals were, when fixed after fixative injection. Greater compliance or distensibility of the diabetic gastrointestinal tract seemed to be one basic ground for dilatation, atony, larger appearance, transit delay, and motile disorders of the diabetic gastrointestinal tract.