Chemically-induced trout model of acute intestinal inflammation using TNBS

•Study of pro-inflammatory potential of 2,4,6-trinitrobenzene sulfonic acid (TNBS) in fish•Rectal administration of TNBS induces intestinal inflammation in rainbow trout•Intestines inflamed using TNBS exhibit increased thickness and immune cell infiltration Chemically-induced models of intestinal inflammation are a useful tool for the study of immune responses and inflammation. Although well established in mammals, application of these models is currently limited in teleosts. Based on a variety of factors, including genetic diversity, known toxicological sensitivity, and economic importance, we propose salmonids as a model family of fishes for studying intestinal inflammation. We present a rainbow trout model of chemically-induced intestinal inflammation using 2,4,6-trinitrobenzene sulfonic acid (TNBS), assessed through histological analysis of primary and secondary intestinal folding, enterocyte morphology, goblet cell size and frequency, tissue layer thickness, and immune cell infiltration. Twenty-four hours after treatment with one of three concentrations of TNBS, trout developed classic signs of intestinal inflammation, including notably increased thickness of primary and secondary folds, and increased immune cell infiltration as compared to controls. This study provides a simple, reproducible model of rapid TNBS-induction of moderate intestinal inflammation.