Abstract
Background: Chitin is a polymer of N-acetylglucosamine with the ability to regulate innate and adaptive immune responses. However, the detailed mechanisms of chitin-mediated regulation of intestinal inflammation are only partially known. Methods: In this study chitin microparticles (CMPs) or phosphate-buffered saline (PBS) were orally administered to acute and chronic colitis models every 3 days for 6 consecutive weeks beginning at weaning age. The effects of this treatment were evaluated by histology, cytokine production, coculture study, and enteric bacterial analysis in dextran sodium sulfate (DSS)-induced colitis or T-cell receptor alpha (TCRα) knockout chronic colitis models. Results: Histologically, chitin-treated mice showed significantly suppressed colitis as compared with PBS-treated mice in both animal models. The production of interferon-gamma (IFN-γ) was upregulated in the mucosa of chitin-treated mice compared with control mice. The major source of IFN-γ-producing cells was CD4+ T cells. In mouse dendritic cells (DCs) we found that CMPs were efficiently internalized and processed within 48 hours. Mesenteric lymph nodes (MLNs) CD4+ T cells isolated from chitin-treated mice produced a 7-fold higher amount of IFN-γ in the culture supernatant after being cocultured with DCs and chitin as compared with the control. Proliferation of carboxyfluorescein succinimidyl ester (CFSE)low CD4+ T cells in MLNs and enteric bacterial translocation rates were significantly reduced in chitin-treated mice when compared with the control. In addition, CMPs improved the imbalance of enteric bacterial compositions and significantly increased interleukin (IL)-10-producing cells in noninflamed colon, indicating the immunoregulatory effects of CMPs in intestinal mucosa. Conclusions: CMPs significantly suppress the development of inflammation by modulating cytokine balance and microbial environment in colon.
Original language | English (US) |
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Pages (from-to) | 1698-1710 |
Number of pages | 13 |
Journal | Inflammatory bowel diseases |
Volume | 18 |
Issue number | 9 |
DOIs | |
State | Published - Sep 2012 |
Externally published | Yes |
Keywords
- animal model
- chitin
- chitinase
- colitis
- cytokine
ASJC Scopus subject areas
- Immunology and Allergy
- Gastroenterology