Increased apoptosis and decreased proliferation of colonic epithelium in dextran sulfate sodium-induced colitis in mice
The pathogenic mechanisms responsible for inflammatory bowel disease, especially ulcerative colitis (UC), are poorly understood. In animal models, the oral administration of dextran sulfate sodium (DSS) induces colitis, which exhibits several clinical and histological features similar
to UC. In addition, the longstanding administration of DSS also induces colon cancer. However, the pathogenic factors responsible for DSS-induced colitis and the subsequent colon cancer also remain unclear. In particular, there are only limited data concerning colonic epithelia cell apoptosis
and proliferation in DSS-induced colitis. Therefore, we investigated the relationships between these factors. Colitis was induced in BALB/cA Jcl mice by 8 days of oral administration of standard diets containing 5% (w/w of diet) DSS. The control mice received the standard diets only. Morphological
changes in the colonic mucosa were evaluated and scored by light microscopy. Apoptosis was studied by the TUNEL assay, and cell proliferation by Ki-67 immunoreactivity. The macroscopic findings showed the most severe inflammation in the distal colon. Epithelial apoptosis increased ≈5-fold
after DSS administration as compared to the controls. On the other hand, the mitotic cells decreased about half-fold as compared to the controls. Ki-67 immunohistochemistry showed that cells with cell cycle arrest at the G0 stage in the crypt increased ≈2-fold as compared to the controls.
In conclusion, the increased apoptosis and decreased proliferation might lead to a breakdown of the epithelial barrier function, and thus facilitate the mucosal invasion of intraluminal microorganisms in DSS-induced colitis.
Document Type: Research Article
Affiliations: Department of Pathology, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan
Publication date: 01 January 2010
- Oncology Reports is a monthly, peer-reviewed journal devoted to the publication of high quality original studies and reviews concerning a broad and comprehensive view of fundamental and applied research in oncology, focusing on carcinogenesis, metastasis and epidemiology.
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