LIGHT AND ELECTRON-MICROSCOPIC OBSERVATIONS OF EPITHELIAL, SHEDDING IN STORED CANINE SMALL-INTESTINE

Simple cold storage of canine small intestine is accompanied by ischem ic damage to the intestinal mucosa. Progression of damage observed dur ing cold storage is unique and has not been observed with other organs . The mucosal damage beans within 15 min after the onset of storage, w ith progressive involvement of the gut as the storage period lengthens . Cytoplasmic blebs develop from the base of the epithelial cells and detach the epithelium from the basal lamina. While the process begins uniformly along the length of the villus, separation of the epithelium occurs first at the villus tip. The epithelium, which is shed into th e intestinal lumen, is otherwise undamaged. Blebbing occurs in enteroe ndocrine and goblet cells and is not restricted to enterocytes. Early blebs occur in proximity to mucosal mast cells and subepithelial nerve s. Tissue damage in cold is possibly related to enzymes that are still active at storage temperatures.