Mucosal Lesions in the Small Intestine of the Cat during Low Flow

The mucosal changes, produced at the villous tips of the cat small intestine during a mimicked shock situation (regional hypotension at 30 mm Hg during nervous vasoconstrictor fibre activation), were examined macro‐and microscopically. Macroscopically, petechial bleedings and ulcerations were regularly seen in the mucosa after a 2 h hypotensive period. The microscopic findings were characterized by epithelial lifting of various degrees at the tips of the villi and in some cases by a complete denudation of the villous tips. Intraluminal perfusion of a segment with oxygenated saline during the hypotension prevented or greatly reduced the mucosal lesions compared to control segments. On the other hand, intraluminal perfusion with nitrogenated saline did not change the mucosal lesions as compared with control. This strongly indicates that hypoxia per se plays an important role in the pathogenesis of the mucosal lesions, while the intestinal content (e.g. energy substrates or enzymes) does not appear to be of any great importance. It is suggested that the hypoxia is caused by an extravascular shunting of oxygen in the intestinal countercurrent exchanger.