Experimental studies on fluid pathophysiology in small intestinal obstruction in the rat. IV. Effects of intraluminal hyperosmolality and simultaneous intravenous infusions on mucosal micromorphology.

A hyperosmolal glucose solution was introduced into a loop of small intestine of specified length and position while intravenous infusions of varying osmolality were given at the same time. The hyperosmolal solution in the lumen caused damage primarily to the tips of the villi where sloughing of the epithelial cells was frequently seen. These defects were repaired by an increase in surface coverage by neighboring epithelial cells, which thus were reduced in height. A varying degree of edema was generally seen in the epithelial cells. The severity of these lesions was modified by intravenous infusions in inverse relationship to the osmolality of the infusions. Thus the defence mounted by the intestinal mucosa against the hyperosmolal solution in the lumen was impaired by the infusion of hypo-osmolal solutions and improved by hyperosmolal solutions. In the latter cases the mucosa maintained a practically normal histological picture.