Inflammatory bowel diseases (IBD) are chronic relapsing disorders of the gastrointestinal tract. Several mouse models for IBD are available, but the acute dextran sulfate sodium (DSS)-induced colitis model is mostly used for preclinical studies. However, this model lacks chronicity and often leads to significant loss of mice. The aim of this study was to establish a refined and translationally relevant model of DSS chronic colitis in BALB/c mice. In the first part, we compared several standard therapeutic (ST) treatments for IBD in the acute DSS colitis model to identify the optimal treatment control for a DSS colitis model as compared to literature data. In the second part, we tested the two most effective ST treatments in a refined model of chronic DSS colitis. Cyclosporine A (CsA) and 6-thioguanine (6-TG) caused considerable reduction of clinical scores in acute DSS colitis. The clinical outcome was confirmed by the results for colon length and by histopathological evaluation. Moreover, CsA and 6-TG considerably reduced mRNA expression of several pro-inflammatory cytokines in spleen and colon. Both compounds also showed a substantial therapeutic effect in the refined model of chronic DSS colitis with regard to clinical scores and histopathology as well as the expression of inflammatory markers. The refined model of chronic DSS colitis reflects important features of IBD and is well suited to test potential IBD therapeutics.

Inflammatory bowel diseases are multifactorial disorders of the gastrointestinal tract with rising incidence worldwide. Current standard therapies are only partially effective and often show severe adverse effects. Thus, novel, more efficient and well-tolerated therapeutic options are urgently needed. We have studied the therapeutic potential of a phytopharmaceutical combining sage and bitter apple (SBA) in the mouse model of chronic dextran sulfate sodium (DSS) colitis. SBA represents a traditional medicine against diarrhea and was shown to exhibit anti-inflammatory effects in vitro. In the chronic DSS colitis model SBA treatment significantly reduced clinical symptoms in a dose-dependent manner. The positive therapeutic effect of SBA was characterized by a decreased histopathological score indicating tissue healing. Moreover, the number of neutrophils as well as the expression of the neutrophil-recruiting chemokine CXCL-1/KC in the colon tissue was significantly reduced, whereas the recruitment of macrophages was induced. Also, the expression of inflammatory markers was significantly suppressed, while the expression of the anti-inflammatory cytokine interleukin-10 was induced in colon tissue following treatment with SBA. Phytopharmaceuticals are increasingly recognized as potential therapeutics in IBD. Thus, based on the results from this study, SBA can be considered as an alternative or supplementary option for IBD therapy.