title: Intrarectal instillation of Clostridium difficile toxin A triggers colonic inflammation and tissue damage: development of a novel and efficient mouse model of Clostridium difficile toxin exposure.
abstract: Clostridium difficile, a major cause of hospital-acquired diarrhea, triggers disease through the release of two toxins, toxin A (TcdA) and toxin B (TcdB). These toxins disrupt the cytoskeleton of the intestinal epithelial cell, increasing intestinal permeability and triggering the release of inflammatory mediators resulting in intestinal injury and inflammation. The most prevalent animal model to study TcdA/TcdB-induced intestinal injury involves injecting toxin into the lumen of a surgically generated "ileal loop." This model is time-consuming and exhibits variability depending on the expertise of the surgeon. Furthermore, the target organ of C. difficile infection (CDI) in humans is the colon, not the ileum. In the current study, we describe a new model of CDI that involves intrarectal instillation of TcdA/TcdB into the mouse colon. The administration of TcdA/TcdB triggered colonic inflammation and neutrophil and macrophage infiltration as well as increased epithelial barrier permeability and intestinal epithelial cell death. The damage and inflammation triggered by TcdA/TcdB isolates from the VPI and 630 strains correlated with the concentration of TcdA and TcdB produced. TcdA/TcdB exposure increased the expression of a number of inflammatory mediators associated with human CDI, including interleukin-6 (IL-6), gamma interferon (IFN-γ), and IL-1β. Finally, we were able to demonstrate that TcdA was much more potent at inducing colonic injury than was TcdB but TcdB could act synergistically with TcdA to exacerbate injury. Taken together, our data indicate that the intrarectal murine model provides a robust and efficient system to examine the effects of TcdA/TcdB on the induction of inflammation and colonic tissue damage in the context of human CDI.
authors.affiliation: Department of Medicine, University of Calgary, Calgary, Canada. simon.hirota@ucalgary.ca
authors.forename: Simon A
authors.initials: SA
authors.lastname: Hirota
authors.forename: Vadim
authors.initials: V
authors.lastname: Iablokov
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Tulk
authors.forename: L Patrick
authors.initials: LP
authors.lastname: Schenck
authors.forename: Helen
authors.initials: H
authors.lastname: Becker
authors.forename: Jimmie
authors.initials: J
authors.lastname: Nguyen
authors.forename: Samir
authors.initials: S
authors.lastname: Al Bashir
authors.forename: Tanis C
authors.initials: TC
authors.lastname: Dingle
authors.forename: Austin
authors.initials: A
authors.lastname: Laing
authors.forename: Jianrui
authors.initials: J
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Jeff
authors.initials: J
authors.lastname: Bolstad
authors.forename: George L
authors.initials: GL
authors.lastname: Mulvey
authors.forename: Glen D
authors.initials: GD
authors.lastname: Armstrong
authors.forename: Wallace K
authors.initials: WK
authors.lastname: MacNaughton
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Muruve
authors.forename: Justin A
authors.initials: JA
authors.lastname: MacDonald
authors.forename: Paul L
authors.initials: PL
authors.lastname: Beck
mesh_terms: D000285:Administration, Rectal; D000818:Animals; D001426:Bacterial Proteins / Q000008:administration & dosage / Q000633:toxicity*; D001427:Bacterial Toxins / Q000008:administration & dosage / Q000633:toxicity*; D016360:Clostridioides difficile / Q000378:metabolism / Q000472:pathogenicity*; D003106:Colon / Q000473:pathology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004761:Enterocolitis, Pseudomembranous / Q000276:immunology / Q000401:mortality / Q000473:pathology*; D004768:Enterotoxins / Q000008:administration & dosage / Q000633:toxicity*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000401:mortality / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile