P-211 Microbial Fingerprinting Detects Intestinal Microbiota Dysbiosis in Zebrafish Models with Chemically-Induced Inflammatory Bowel Disease

Abstract

It is believed that inflammatory bowel disease (IBD) involves a breakdown in interactions between the host immune response and the resident commensal microbiota. Recent studies have suggested gut physiology and pathology relevant to human IBD can be rapidly modeled in zebrafish larvae with a number of advantages in comparison with murine models. The aim of this study was to investigate the dysbiosis of intestinal microbiota in zebrafish models with IBD using culture-independent techniques. IBD was induced by exposing larval zebrafish to trinitrobenzenesulfonic acid (TNBS) with different concentrations (0, 25, 50 and 75 μg/ml). Assays were performed using larval zebrafish collected at 4, 6 and 8 days post fertilization (dpf). Pathology was assessed by histology and immunofluorescence. Changes in intestinal microflora were evaluated by denaturing gradient gel electrophoresis (DGGE) and the predominant bacterial composition was determined with DNA sequencing and BLAST. Larval zebrafish exposed to TNBS displayed intestinal-fold architecture disruption and inflammation reminiscent of human IBD including impaired epithelial integrity, expanded crypts/reduced villi and expanded gut lumen. In addition, there were significant changes in goblet cell numbers and a marked induction of inflammatory cytokines (TNF-α). In this study, we defined a reduced biodiversity of gut bacterial community in IBD. The intestinal microbiota dysbiosis in zebrafish larvae with IBD was characterized by an increased proportion of Proteobacteria (especially Limnobacter sp. and Comamonas sp.) and significantly correlated with enterocolitis scores (Pearson correlation P < 0.05). This is the first description of intestinal microbiota dysbiosis in zebrafish models with TNBS-induced IBD, showing a predominance of some opportunistic pathogenic bacteria and a decrease in beneficial bacterial species. Prevention or reversal of this dysbiosis may be a viable option for reducing the incidence and severity of IBD.