Prevention of Chronic Experimental Colitis Induced by Dextran Sulphate Sodium (DSS) in Mice Treated with FR91

Abstract

One of the main treatments currently used in humans to fight cancer is chemotherapy. A huge number of compounds with antitumor activity are present in nature, and many of their derivatives are produced by microorganisms. However, the search for new drugs still represents a main objective for cancer therapy, due to drug toxicity and resistance to multiple chemotherapeutic drugs. In animal models, a short-time oral administration of dextran sulfate sodium (DSS) induces colitis, which exhibits several clinical and histological features similar to ulcerative colitis (UC). However, the pathogenic factors responsible for DSS-induced colitis and the subsequent colon cancer also remain unclear. We investigated the effect of FR91, a standardized lysate of microbial cells belonging to the Bacillus genus which has been previously shown to have significant immunomodulatory effects, against intestinal inflammation. Colitis was induced in mice during 5 weeks by oral administration 2% (DSS). Morphological changes in the colonic mucosa were evaluated by hematoxylin-eosin staining and immunohistochemistry methods. Adenocarcinoma and cryptal cells of the dysplastic epithelium showed cathenin-β, MLH1, APC, and p53 expression, together with increased production of IFN-γ. In our model, the optimal dose response was the 20% FR91 concentration, where no histological alterations or mild DSS-induced lesions were observed. These results indicate that FR91 may act as a chemopreventive agent against inflammation in mice DSS-induced colitis.