Cellular Proliferation of Intestinal Epithelia in the Rat Two Months after Partial Resection of the Ileum

Abstract

Sprague-Dawley rats subjected 2 months previously to partial resection (10 per cent) of the small intestine and their controls were injected with tritiated thymidine and sacrificed at 2 and 23 hours. Segments of the duodenum, jejunum, and ileum were autoradiographed, and the migration of the labelled cells during the period between 2 and 23 hours was measured with an eyepiece micrometer. The cells had migrated 35, 42, and 34 per cent of the total distance from thecrypts to the tips of the villi in the control segments of duodenum, ileum, and jejunum respectively, and 43, 90, and 82 per cent, respectively, in similar segments from resected animals. The rate of migration in the portion of the intestine remaining after resection was approximately three times the normal rate in the ileum, twice the normal rate in the jejunum, and showed an increase of one-third in the duodenum. These results demonstrate that the rate of cell renewal is considerably greater in the remaining portion of the intestine of resected animals than in normal intestine. The increased rate of migration after resection, together with the increase in the height of the villi, resulted in an increase in the rate of cell renewal amounting to 141 per cent in the ileum, l l 4 p e r cent in the jejunum, and 23 per cent in the duodenum when compared with control segments.This study is the fourth in a series of reports on the effects of "partial" (10 per cent) resection of the small intestine. The first three dealt with intestinal absorption, enzymatic activity, hypertrophy, and metabolism in the resected rat (1 3); the present study is concerned with the effects of resection on cellular dynamics. As Leblond (4) has stated: "Many tissues are in a state of flux, their (cell) population size varying chiefly with the rates of reproduction, on the one hand, and with the rates of conversion to non-reproductive units or of destruction, on the other hand. The state of a tissue fluctuates with its physical and *

Population Dynamics of Intestinal Epithelia in the Rat Two Months After Partial Resection of the Ileum

“…The life span of an epithelial cell on the villus in the duodenum, jejunum, and ileum, respectively, of resected rats was 82, 46, and 42 per cent of the control values. Our data confirm the findings of the previous study (1).…”

“…The increased rate of migration of intestinal crypt cells onto villi in the present study was of the magnitude that would be expected from the previously reported reduction in the life span of epithelial cells in the jejunum and ileum of resected rats (1). In the duodenum of resected rats, the epithelial cells emerge from the crypts and move up the villi at nearly normal rates and have a nearly normal life span.…”

“…As reported previously (1), resection of I0 per cent of the small intestine (removal of 10 cm of ileum) in rats was followed by a pronounced increase in the rate of migration of the epithelial cells covering the villi in the remaining portion of small intestine. Two months after resection, the distance traveled by mucosal cells examined 2 and 24 hours after labeling with tritiated thymidine was increased by approximately 23 per cent in the duodenum, 114 per cent in the jejunum, and 141 per cent in the ileum.…”

“…The effects of partial resection of the small intestine in the rat have been described previously (1). Two months after resection, the rate of migration of cells up villi of the shortened intestine was increased and the increase was found to be greatest in segments nearest the site of resection.…”

The relationship between intestinal histology and function as shown by compensatory enlargement of remnant villi after midgut resection in chickens

“…This physiological activation of the remnant intestine corresponds with histological alterations wherein villus height and cell mitosis numbers were higher in all intestinal segments of jejunal resection groups. This structural reconstruction after intestinal resection corresponds to results in other studies; rats showed an increased cell population in the colonic crypt (Zufarov and Baibekov, 1971) and an elevated cell migration rate and villus height (Loran and Althausen, 1960) in the remnant intestine after intestinal resection. Hypertrophied villus height (Navidshad et al, 2010) and cell mitosis numbers (Buwjoom et al, 2010) were reported with increased body weight in intact chickens, suggesting that remnant villi in this study were also hypertrophied.…”