Direct effects of endotoxin on canine gastric mucosal permeability and morphology

Abstract

The effects of endotoxin on gastric mucosal permeability and morphology were studied by intra-arterial infusion of sublethal doses of endotoxin into a single artery perfusing an exteriorized segment of canine stomach. Endotoxin infusion produced a profound change in mucosal appearance from bright, uniform red to mottled, palewhite discoloration when exposed to acid or mannitol. Gross erosions occurred in four of 13 mucosae bathed with 0.15 N HCl within 1 hr of infusion of endotoxin in the absence of arterial hypotension. Histological changes seen in most experiments include release of mucus from surface epithelial cells and elevation of the epithelium from the basement membrane. In more advanced lesions, severe injury extended into the gastric glands and surrounding connective tissue with cellular necrosis. In spite of gross and microscopic gastric mucosal injury, no significant change was seen in hydrogen ion back diffusion or sodium efflux. These observations suggest that gastric mucosal injuries can occur in endotoxemia without systemic arterial hypotension and that anatomical mucosal injuries are not associated with the destruction of the hydrogen-sodium permeability barrier.