Efficacy of Phytotherapeutics in a Refined Chronic DSS-Induced Colitis Model

The clinical forms of inflammatory bowel disease (IBD), ulcerative colitis and Crohn‘s disease, are chronic-relapsing inflammatory disorders of the gastrointestinal tract. The model of dextran sulfate sodium (DSS)-induced acute colitis is one of the most widely used models in IBD research. Although it reflects certain aspects of clinical symptoms, a caveat is the lack of chronicity and a chronic inflammatory response. We aimed to develop a refined chronic DSS model that reflects signs of chronic inflammation for evaluating the effects of phytopharmaceuticals based on Citrullus colocynthis and Salvia officinalis.

To monitor the induction and persistence of colitis, body weight, stool consistency, and colonic hemorrhage were assessed daily. To evaluate morphological changes and the extent of local inflammatory response in the colon, we determined a histological score based on tissue sections. Chronification of inflammatory processes was evaluated by analyzing pro-inflammatory cytokines.

We propose a refined model of DSS-induced chronic colitis that reflects important features of IBD without excessive weight loss. Pathology is mainly characterized by diarrhea and blood in stool and can be significantly reduced by 6-thioguanine as an approved therapeutic for IBD. The therapeutic efficacy and mode of action of several phytopharmaceuticals is tested in the established model.