Intestinal Strangulation in Clostridium perfringens -Monocontaminated Rats

Abstract

Ischemic and hemorrhagic strangulation of closed intestinal segments was studied in germ-free rats individually contaminated with one of seven separate strains of Clostridiwn perfringens type A. The principal findings were that (i) the monocontaminated rats with ischemic or hemorrhagic intestinal strangulation died at the same rapid rate; (ii) intraintestinal blood did not augment the action of C. perfringens in the presence of ischemic strangulation; (iii) although some strains were more toxic than others, several food-poisoning strains were as rapidly fatal as the classical strains; and (iv) the massive amounts of gas produced by some of these strains probably led to the early rupture of the closed segments and rapid death of the animals. The secondary findings were that (i) the injection of C. perfringens into the lumen of the distal small intestine of the germ-free rat produced the typical lesions of pneumatosis cystoides intestinalis; and (ii) most of the strains of C. perfringens established themselves throughout the gastrointestinal tract of the unoperated germ-free rat.The intestinal bacteria are a major factor in death from intestinal strangulation. Our laboratories have previously studied intestinal strangulation in conventional, monocontaminated (Sphaerophorus necrophorus and Escherichia coli), and germ-free rats (14-17).The clostridia are common anaerobic sporeforming inhabitants of the gastrointestinal tract in man and animals and have been frequently implicated in death from intestinal strangulation. This paper summarizes a series of experiments on the ischemic and hemorrhagic strangulation of closed intestinal segments in germ-free rats monocontaminated with one of seven different classical (gas gangrene) or foodpoisoning strains of Clostridium perfringens type A. MATERIALS AND METHODSOperative procedures. Sprague-Dawley germ-free rats, 130 of each sex, were used in these intestinal strangulation experiments. The average weights and hematocrits were, respectively: males, 439 28[standard deviation (SD)] g; 54.3 ± 2.8 (SD) %; and females, 284 i 19 (SD) g; 50.8 i 2.2 (SD) %. Approximately 18 germ-free rats of each sex were singly caged in each of nine separate flexible-film housing isolators with individually attached operating chambers.One of five separate operative procedures was done on each animal. Under intramuscular sodium pento-barbital anesthesia (25 mg/kg of body weight), the peritoneal cavity was opened through a midline incision. In the first type of operation, either 1 ml of normal saline or 1 ml of a C. perfringens suspension was injected through a no. 30 needle into the lumen of the distal ileum. In the second, a 20-cm segment of distal ileum was isolated by ligating its ends with no. 2 silk. After dividing the bowel above the proximal and below the distal ligatures, an end-to-end anastomosis with interrupted, inverting 6-0 silk was done to restore the intestinal continuity. One milliliter of homologous, heparinized blood (10 units of heparin/ ml) was injected into the lumen of the isola...