Research Report
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World J Gastroenterol. Dec 7, 2014; 20(45): 17084-17091
Published online Dec 7, 2014. doi: 10.3748/wjg.v20.i45.17084
Clostridium difficile infection aggravates colitis in interleukin 10-deficient mice
Mi Na Kim, Seong-Joon Koh, Jung Mogg Kim, Jong Pil Im, Hyun Chae Jung, Joo Sung Kim
Mi Na Kim, Seoul National University Healthcare System Gangnam Center, Seoul National University Hospital, Seoul 135-984, South Korea
Seong-Joon Koh, Department of Internal Medicine, Seoul National University Boramae Hospital, Seoul National University College of Medicine, Seoul 157-707, South Korea
Jung Mogg Kim, Department of Microbiology, Hanyang University College of Medicine, Seoul 133-792, South Korea
Jong Pil Im, Hyun Chae Jung, Joo Sung Kim, Department of Internal Medicine, Liver Research Institute, Seoul National University College of Medicine, Seoul 110-744, South Korea
Author contributions: Kim MN and Kim JS conceived of and designed the study, and wrote the paper; Kim MN and Koh SJ performed the experiments; Kim MN, Kim JM, Im JP, Jung HC and Kim JS analyzed the data; all authors read and approved the final version of the paper.
Correspondence to: Joo Sung Kim, MD, PhD, Department of Internal Medicine, Liver Research Institute, Seoul National University College of Medicine, 103 Daehak-ro, Chongno-gu, Seoul 110-744, South Korea. jooskim@snu.ac.kr
Telephone: +82-2-7408112 Fax: +82-2-7436701
Received: May 17, 2014
Revised: June 27, 2014
Accepted: July 29, 2014
Published online: December 7, 2014
Abstract

AIM: To investigate the effect of Clostridium difficile (C. difficile) infection in an interleukin 10-deficient (IL-10-/-) mouse model of inflammatory bowel disease.

METHODS: Bone marrow-derived dendritic cells isolated from wild type (WT) and IL-10-/-mice were stimulated for 4 h with C. difficile toxin A (200 μg/mL), and gene expression of interferon (IFN)-γ, IL-12 and IL-23 was determined by real-time reverse transcription polymerase chain reaction. WT and IL-10-/- mice (n = 20 each) were exposed to an antibiotic cocktail for three days and then were injected with clindamycin (i.p.). Mice (n = 10 WT, 10 IL-10-/-) were then challenged with oral administration of C. difficile (1 × 105 colony forming units of strain VPI 10463). Animals were monitored daily for 7 d for signs of colitis. Colonic tissue samples were evaluated for cytokine gene expression and histopathologic analysis.

RESULTS: C. difficile toxin A treatment induced IFN-γ gene expression to a level that was significantly higher in BDMCs from IL-10-/- compared to those from WT mice (P < 0.05). However, expression of IL-12 and IL-23 was not different among the groups. Following C. difficile administration, mice developed diarrhea and lost weight within 2-3 d. Weight loss was significantly greater in IL-10-/- compared to WT mice (P < 0.05). C. difficile infection induced histopathologic features typical of colitis in both IL-10-/- and WT mice. The histopathologic severity score was significantly higher in the IL-10-/- than in WT mice (mean ± standard error; 5.50 ± 0.53 vs 2.44 ± 0.46; P < 0.05). This was accompanied by a significantly greater increase in IFN-γ gene expression in colonic tissues from IL-10-/- than from WT mice challenged with C. difficile (P < 0.05).

CONCLUSION: These results indicate that colitis is more severe after C. difficile infection in IL-10-/-mice, and that IFN-γ expression is involved in this process.

Keywords: Clostridium difficile, Inflammatory bowel disease, Interleukin 10-deficient mice, Interferon-γ, Colitis

Core tip: The results of this study indicate that Clostridium difficile (C. difficile) infection induces more severe colitis in the interleukin 10-deficient (IL-10-/-) mouse model of inflammatory bowel disease (IBD). Moreover, induction of interferon-γ gene expression was greater in the IL-10-/- mice and their bone marrow-derived dendritic cells compared to wild type mice following C. difficile infection and exposure to C. difficile toxin A, respectively. This study demonstrates the establishment of C. difficile-aggravated colitis in an IBD animal model, which provides a useful tool for studying the relationship between C. difficile and host immune response of the gut in IBD.