Different wild type strains of zebrafish show divergent susceptibility to TNBS-induced intestinal inflammation displaying distinct immune cell profiles

Little is known about the diversity in immune profile of the different wild type strains of zebrafish (Danio rerio), despite its growing popularity as an animal model to study human diseases and drug testing. In the case of data resulting from modeling human diseases, differences in the background Danio fishes have rarely been taken into consideration when interpreting results and this is potentially problematic, as many studies not even mention the source and strain of the animals. In this study, we hypothesized that different wild type zebrafish strains could present distinct immune traits. To address the differences in immune responses between two commonly used wild type strains of zebrafish, AB and Tübingen (TU), we used an intestinal inflammation model induced by 2,4,6-Trinitrobenzenesulfonic acid (TNBS) and characterized the susceptibility and immune profile in these two strains. Our data demonstrates significant differences in survival between AB and TU strains when exposed to TNBS, suggesting important physiological differences in how these strains respond to inflammatory challenges. We observed that the AB strain presented increased mortality, higher neutrophilic intestinal infiltration, decreased goblet cell numbers and decreased IL-10 expression when exposed to TNBS, compared to the TU strain. In summary, our study demonstrates strain-specific immunological responses in AB and TU animals. Finally, the significant variations in strain-related susceptibility to inflammation and the differences in the immune profile shown here, highlight that the background of each strain need to be considered when utilizing zebrafish to model diseases and for drug screening purposes, thus better immune characterization of the diverse wild type strains of zebrafish is imperative.