EFFECT OF TOTAL COLECTOMY ON MORPHOLOGY AND ABSORPTIVE CAPACITY OF ILEUM IN RAT

The mechanism of adaptation of intestinal absorption after colectomy has not been established. This adaptation was studied by measuring morphologic changes and absorptive capacity of the ileum before and 2 months after total colectomy and ileoproctostomy in rats. The water-absorptive capacity of ileum was determined in situ by infusing a 10-cm. segment at 0.2 ml./minute with an isotonic solution with a nonabsorbable marker. Net water absorption in the ileum increased from 0.17 ± 0.012 ml./cm./hour in preoperative and control animals to 0.28 ± 0.034 ml./cm./hour 2 months after colectomy (P < 0.01). Average ileal villus length increased 42% and the number of mucosal cells from crypt to tip of villus increased 51%. These findings indicate that both ileal absorptive surface and absorptive capacity increase after total colectomy in the rat and suggest that the enhancement of water-absorptive capacity in the intestinal remnant is the mechanism of functional adaptation after colectomy. © 1969.