Objective - To evaluate the morphologic and physiologic changes induced by Clostridium perfringens type A α toxin in the ileum and colon of sheep. Sample Population - 16 ligated intestinal loops in 4 Merino lambs and 18 explants of ileum and colon from slaughtered lambs. Procedure - α Toxin-induced fluid accumulation was evaluated in ligated ileal and colonic loops of sheep. Tissues were evaluated morphologically by use of gross and histologic examination. Effects of toxin on in vitro intestinal net water transport were tested in modified Ussing chambers. Results - Ovine ileal and colonic loops incubated with C perfringens type A α toxin retained more fluid than control loops. Histologically, in the ileum of lambs inoculated with 300 LD50 of α toxin/mL, there was a mild to moderate multifocal infiltration of neutrophils in the lamina propria and submucosa. The colonic loops of lambs inoculated with 30 or 300 LD50 of α toxin/mL had excessive mucus in the lumen, a moderate amount of neutrophils mixed with mucus in the intestinal lumen, and moderate multifocal infiltration of the lamina propria and submucosa with neutrophils; the blood vessels of these layers were engorged with neutrophils. In vitro measurements of water transport also revealed inhibition of net epithelial water absorption in ileum and colon incubated with α toxin on the mucosal side. Conclusions and Clinical Relevance - These results indicate that α toxin induces alterations in sheep intestine. Clostridium perfringens type A organisms that produce α toxin could be responsible for diseases of intestinal origin in some ruminants.
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