Histopathological effect of botulinum C2 toxin on mouse intestines.

Botulinum C2 toxin has histopathological activity in the mouse intestine and induces fluid accumulation in intestinal loops. The toxin caused degenerative and necrotic changes in the intestinal mucosa: intracellular vacuolization of epithelial cells, desquamation and necrosis of the villous epithelium, intercellular edema, and infiltration of lymphocytes and histiocytes. The detectable changes in the morphology of the intestinal mucosa preceded the increase in fluid accumulation in intestinal loops. Intraluminal injection of botulinum C2 toxin also induced the leakage of plasma protein into the intestinal lumen as determined by the extravasation of Evans blue. In contrast to botulinum C2 toxin, cholera and Clostridium perfringens enterotoxin controls caused a very slight protein leakage, although these toxins induced marked fluid accumulation in intestinal loops. The results indicate that the mode of action of botulinum C2 toxin in eliciting the secretory response is distinguishable from those of cholera and C. perfringens enterotoxins and suggest that botulinum C2 toxin induces the secretory response by cytopathic effect(s) on the epithelial cells of the intestine.