Effect of dietary oligofructose and inulin on colonic preneoplastic aberrant crypt foci inhibition

Oligofructose and inulin, naturally-occurring fermentable chicory fructans,have been shown to stimulate the growth of bifidobacteria which areregarded as beneficial strains in the colon and inhibit coloncarcinogenesis in the laboratory animal models. The present study wasdesigned to determine the effect of oligofructose and inulin on theazoxymethane (AOM)-induced preneoplastic lesions such as aberrant cryptfoci (ACF) formation in the colon of male F344 rats. At 5 weeks of age,groups of animals were fed the AIN-76A (control) and the experimental dietscontaining 10% oligofructose or inulin. At 7 weeks of age, all animalsreceived s.c. injection of AOM dissolved in normal saline at a dose rate of15 mg/kg body wt, once weekly for 2 weeks. The animals were necropsied 7weeks after the last AOM injection, and the ACF were visualized under lightmicroscopy in the formalin-fixed, unsectioned methylene blue-stainedcolons. They were distinguished by their increased size, more prominentepithelial cells and pericryptal space. The feeding of oligofructose orinulin significantly inhibited the ACF formation and the crypt multiplicityin the colon. The degree of ACF inhibition was more pronounced in animalsfed inulin than in those fed oligofructose. The findings suggest thatchicory fructan supplements inhibit ACF formation, an early preneoplasticmarker of malignant potential in the process of colon carcinogenesis.