Oxazolone-induced enterocolitis in zebrafish depends on the composition of the intestinal microbiota.
OBJECTIVE
The pathogenesis of inflammatory bowel disease involves dysfunctional mucosal immune responses to commensal bacteria in genetically predisposed hosts. Interactions between host cells and bacteria are complicated, making it a challenge to assess their relative contribution to intestinal pathology. We developed a zebrafish model of enterocolitis to study these interactions.


METHODS
Enterocolitis was induced by intrarectal administration of the hapten oxazolone in adult wild-type and myeloperoxidase-reporter transgenic zebrafish in the presence or absence of antibiotics. Intestinal inflammation was evaluated by histological and flow cytometry analyses and cytokine profiling with quantitative real-time polymerase chain reaction. Changes in the composition of the intestinal microbiota following antibiotic administration were assessed by 16SrRNA sequencing and bacterial load was quantified by culture on nonselective media (colony-forming units).


RESULTS
In zebrafish, the infiltrate and severity of oxazolone-induced enterocolitis are influenced by the composition of the microbiota. Inflammation is characterized by granulocyte influx; epithelial damage; goblet cell depletion; and increased expression of interleukin-1beta, tumor necrosis factor-alpha, and interleukin-10. Zebrafish given vancomycin had bacterial populations dominated by Fusobacteria and reduced enterocolitis scores, intestinal damage, and percentages of infiltrating neutrophils and eosinophils. In contrast, zebrafish given colistin sulphate had a predominance of proteobacteria and reduced eosinophil and lymphocyte infiltration, but enterocolitis scores were not reduced.


CONCLUSIONS
In zebrafish with oxazolone-induced enterocolitis, components of the intestinal microbiota affect the severity and composition of the intestinal infiltrate.
Brugman
Sylvia
S
Laboratory of Pediatrics, Pediatric Gastroenterology, Erasmus Medical Center, Rotterdam, The Netherlands.
Liu
Kit-Yeng
KY
Lindenbergh-Kortleve
Dicky
D
Samsom
Janneke N
JN
Furuta
Glenn T
GT
Renshaw
Stephen A
SA
Willemsen
Rob
R
Nieuwenhuis
Edward E S
EE
D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D003091:Colistin / Q000627:therapeutic use; D004195:Disease Models, Animal; D004760:Enterocolitis / Q000188:drug therapy / Q000382:microbiology* / Q000473:pathology*; D007422:Intestines / Q000187:drug effects / Q000382:microbiology* / Q000473:pathology; D010081:Oxazolone / Q000494:pharmacology; D014640:Vancomycin / Q000627:therapeutic use; D015027:Zebrafish
D000276:Adjuvants, Immunologic; D000900:Anti-Bacterial Agents; D010081:Oxazolone; D014640:Vancomycin; D003091:Colistin