AJP - Gastrointestinal and Liver Physiology, Vol 249, Issue 3 382-G388, Copyright © 1985 by American Physiological Society
Influence of luminal pH on rat large bowel epithelial cell cycle
J. R. Lupton, D. M. Coder and L. R. Jacobs
The influence of luminal pH on the colonic epithelial cell cycle was
studied by means of dietary modification to produce acidification of
colonic contents. Forty male Sprague-Dawley rats were fed one of four
diets: defined fiber free, fiber free diluted by either 100 g/kg lactulose
or sorbitol, or 25 g/kg of MgSO4. After 2 wk, in vivo pH measurements were
recorded at laparotomy under ether anesthesia in the cecum and proximal,
mid-, and distal colon. Epithelial cells, isolated from these same regions,
were measured for DNA content with flow cytometry in order to determine
cell cycle stage. The pH values in all intestinal regions were highest with
MgSO4 and then fiber free, sorbitol, and lactulose, the most acidic. In
contrast, the percentage of cells in S phase (actively synthesizing DNA)
was highest with lactulose and least with MgSO4. There was a significant
inverse correlation between luminal pH and percent cells in S phase in the
cecum (P less than 0.01), proximal colon (P less than 0.05), and distal
colon (P less than 0.01). These results show that acidification of colonic
contents by diet modification leads to increased epithelial cell
proliferation.
