Influence of a diverting colostomy on epithelial cell proliferation in the colon of rats.

The effect of a transverse colostomy was compared to a sham operation and to transsection of the colon with reanastomosis in rats. The autoradiographic study after labeling with tritiated thymidine showed a significant decrease in proliferative activity at 5 days and at 3 weeks in the colonic segment distal to the colostomy. This observation was confirmed by the occurrence of mucosal atrophy and by a significant decrease in the mucosal DNA synthesis activity. It was concluded that the intraluminal presence of fecal bulk is an important factor in the maintenance of cell renewal in the colon of rats. Other factors seem, however, to be involved since a delayed but significant decrease in proliferative parameters was also observed proximal to the colostomy; no mucosal atrophy occurred in the latter segment.