Stimulation of apoptosis by two prebiotic chicory fructans in the rat colon

Prebiotics, in particular the chicory derived beta (2-1) fructans, have bee n shown to exert cancer protective effects in animal models. The present st udy was carried out to determine the effects of two chicory fructans-oligof ructose (RaftiloseP95; average degree of polymerization DP = 4) and long ch ain inulin (RaftilineHP; average DP = 25), on apoptosis and bacterial metab olism associated with carcinogenesis. Eighteen rats were fed a stock diet f or one week. Three groups of six animals were then fed one of three diets: basal, basal with oligofructose (5%w/w) or basal with long chain inulin (5% w/w), for a three week period, All animals were then dosed with 1, 2-dimeth ylhydrazine and killed 24 h later. The mean number of apoptotic cells per c rypt was significantly higher in the colon of rats fed oligofructose (P = 0 .049) and long chain inulin (P = 0.017) as compared to those fed the basal diet alone. This suggests that oligofructose as well as the long chain inul in exert protective effects at an early stage in the onset of cancer, as th e supplements were effective soon after the carcinogen insult. Comparison o f the apoptotic indices between the two oligosaccharide diets showed no sig nificant difference even though the mean apoptotic index was higher in anim als fed long chain inulin, For all animals, apoptosis was significantly hig her in the distal colon as compared to the proximal colon (P = 0.0002) howe ver no significant site specific effect of diet occurred. There were no sig nificant dietary effects on bacterial enzyme activities or ammonia concentr ation despite a trend towards increased colonic beta -glucosidase and reduc ed ammonia concentration during the oligosaccharide diets, This is the firs t time that a significant effect of chicory fructans on apoptosis has been shown and the results contribute to the growing evidence that chicory fruct ans may have cancer preventing properties.