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Activated Notch Signaling Cascade is Correlated with Stem Cell Differentiation Toward Absorptive Progenitors after Massive Small Bowel Resection in a Rat

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AJP Gastrointestinal and Liver Physiology

Published online on

Abstract

Notch signaling is thought to act to drive cell versification in the lining of the small intestine. The purpose of the present study was to evaluate the role of Notch signaling pathway in stem cell differentiationin the late stages of intestinal adaptation after massive small bowel resection in a rat. Male Sprague-Dawley rats were randomly assigned to one of two experimental groups of 8 rats each: Sham rats underwent bowel transection and re-anastomosis, SBS- rats underwent 75% small bowel resection. Rats were sacrificed on day 14. Illumina's Digital Gene Expression (DGE) analysis was used to determine Notch signaling gene expression profiling. Notch-related gene and protein expression were determined using Real Time PCR, Western blotting and immunohistochemistry. From 7 investigated Notch-related (by DGE analysis) genes 6 genes were up-regulated in SBS vs control animals with a relative change in gene expression level of 20% or more. A significant up-regulation of Notch signaling related genes in resected animals was accompanied by a significant increase in Notch-1 protein levels (Western Blot) and a significant increase in the number of NOTCH-1 and Hes -1 (target gene) positive cells (immunohistochemistry) compared to sham animals. Evaluation of cell differentiation has shown a strong increase in total number of absorptive cells (unchanged secretory cells) compared to control rats. In conclusion, two weeks after bowel resection in rats, stimulated Notch signaling directs crypt cells population toward absorptive progenitors.