Experimental chronic gastric ulcer due to ischemia in rats.

Ligation of the left gastric and right gastroepiploic arteries and veins resulted in chronic gastric ulcer formation in the rat. Linear mucosal corpus hemorrhages appeared within 8 hr of ligation. By 2 days large corpus hemorrhagic erosions were present. A single, large ulcer involving nearly the entire corpus was present at 3-5 days. In the ulcerated area the mucosa and muscularis mucosae were destroyed, thick granulation tissue filled the submucosa and the muscularis propria was severely damaged. Progressive healing occurred thereafter and 75% of the ulcers healed completely grossly in 2-8 weeks. Histologic studies showed that healing and mucosal regeneration occurred by the outgrowth of a layer of cells from the adjacent intact epithelium extending over the surface of the ulcer. Invaginations from this covering layer of cells formed a glandular mucosa composed of mucous cells. Later parietal and chief cells appeared, and eventually (6 months) a normal corpus-type mucosa covered the entire corpus. With time smooth-muscle fibers appeared in the outer half of the dense submucosal granulation tissue and eventually a normal muscularis mucosae, submucosa, and muscularis propria were present (6-12 months). These studies show that: (1) ischemia can give rise to chronic gastric ulcer, and (2) all elements of the gastric wall, including the mucosa, the muscularis mucosae, and the muscularis propria can fully regenerate.