Effect of timed occlusions at various levels of mesenteric arteries and veins: correlative study of arteriographic and histologic patterns of rat gut.

Abstract

Vascular disease of the small and large intestine has been of interest to the medical profession for many years. In recent years, as more examples of such disease are recognized, it has assumed even greater importance. The disease has been investigated by means of plain and barium sulfate roentgenograms and by arteriography. The results of these studies have been reported by many authors, including Nelson and Eggleston (5), Schwartz et al. (6, 7), Wang and Reeves (8), and Wolf and Marshak (9). Experimental studies of human and canine mesenteric vascular disease have also been reported (1, 2, 6, 7). With advances in diagnostic arteriography and the introduction of the Seldinger technic, selective catheterization of mesenteric vessels became practical. To our knowledge, however, no systematic experiments have been reported which correlate the histologic and arteriographic patterns of bowel in occlusive disease of the superior mesenteric vessels. In the studies reported here, the histologic changes are compared with the arteriographic in experimental occlusive vascular disease of the bowel in rats. Material and Method White female Sprague-Dawley rats, weighing 250 to 350 g, were used. A different site of superior mesenteric arterial or of venous occlusion, or of both, was chosen in each experiment (Figs. 1–5), according to the following groups: Group I: Root occlusion of both the superior mesenteric artery and vein (47 rats). Group II: Root occlusion of the superior mesenteric vein (47 rats). Group III: Occlusion of the superior mesenteric artery and vein ten divisions proximal to the terminal vascular division supplying the distal ileum and cecum (28 rats). Group IV: Occlusion of the terminal branches of the superior mesenteric artery and vein that supply the terminal ileum and cecum (22 rats). Group V: Preterminal occlusion of superior mesenteric artery and vein with occlusion of the collateral blood supply (26 rats). These sites were chosen in order to study differences, if any, between changes produced by closure of main visceral vessels and terminal branches. Group VI: Controls: The effects of surgical mobilization and handling of the bowel and of arteriography were established in a control group of rats. Six of 13 rats in the control group were sacrificed and subjected to arteriography. The remaining 7 rats underwent surgical exploration with bowel mobilization, replacement, and abdominal closure. Twenty-four hours later these 7 rats were killed, and arteriograms were obtained in the same manner as that employed for the test animals. At surgery, the bowel was delivered outside the abdominal cavity, and the superior mesenteric vessels were identified. These were occluded with a surgical forceps or with surgical ties.