Ischaemic colitis in the experimental animal. I. Comparison of the effects of acute and subacute vascular occlusion.

Abstract

SUMMARY Acute ligation of the common colic and caudal mesenteric artery in the dog led to ischaemic colitis, whereas the acute ligation of the common colic artery and gradual occlusion of the caudal mesenteric artery by an ameroid plastic device did not lead to ischaemic disease. These findings suggest that the collateral blood vessels do not open up rapidly enough to prevent ischaemic change when the two major arteries are acutely ligated.For a number of years, attempts have been made to render the large bowel ischaemic experimentally. Boley et al. (1963) carried out experiments in which they ligated the colonic arteries in dogs and they also undertook other studies in which either venous or combined arterial and venous interruption was effected. They produced appearances some of which resembled ischaemic colitis in man.Marston et al. (1969) adopted similar techniques which involved acute ligation of the common colic, the caudal mesenteric, and the marginal arteries in the dog. The extent of devascularisation ranged from the acute ligation of the caudal mesenteric artery alone, to subtotal devascularisation where all three arteries were ligated at once. Definite structural lesions were produced which varied in timing and severity according to the degree of the devascularisation procedure.Boley et a!. (1965) investigated the effects of blockage of the vasa recta with microsphere emboli. Ceramic and glass microspheres varying in diameter from 35 to 100 microns were injected into the caudal mesenteric artery in dogs. This resulted in a spectrum ofpathological change ranging from minimalmucosal oedema to rapid total intestinal necrosis, the severity depending on the size and quantity of the spheres injected. The larger the quantity and the smaller the spheres the greater was the damage produced.Using the Seldinger technique, Ranniger and Scheiner (1967) injected lead pellets into the cranial (superior) mesenteric artery of dogs and found that the degree of vascular embarrassment produced