Effects of Konjac glucomannan, inulin and cellulose on colonocyte DNA Integrity and anti‐genotoxic responses against azoxymethane in mice fed a high‐fat diet

Abstract

The aim of study was to compare effects of konjac glucomannan (KGM), inulin, and cellulose on the DNA integrity and gene expressions of enzymes in colonocytes of C57BL/6J mice before and within 24 h of a single dose of azoxymethane (AOM). Six‐week‐old mice were fed a control diet with 20% (w/w) corn oil and 1% (w/w) cellulose or that supplemented with KGM, inulin or cellulose (5%, w/w) for 3 weeks. Fresh feces were collected 3 days prior the AOM (10 mg/kg BW, i. p.) injection on day 22. Each mouse was killed before (0 h), or 6, 24 h after the injection. The colonocytes were immediately isolated for further analyses of DNA damage (denoted by tail moment) and gene expressions. The DNA damage of colonocytes was the lowest in the inulin group at 0 h. The increased AOM‐induced DNA damage was ameliorated by KGM and inulin. The initial (0 h) gene expressions of glutathione peroxidase 2 (GPX2) in the colonocytes were lower in the control and cellulose groups, which may lead to AOM‐induced up‐regulation (to ≥ 2 folds of initial level) within 24 h. Addition of KGM or inulin to control diet beneficially promoted the concentration and daily fecal excretion of bifidobacteria and lactobacilli. The present study suggests that KGM and inulin protect the colonocytes from DNA damage induced by AOM, which may be related to their prebiotic effects. This study was supported by the National Science Council Grant NSC‐101–2320‐B‐040–018 ‐MY2, Taiwan.