title: Effects of dairy products on heterocyclic aromatic amine-induced rat colon carcinogenesis.
abstract: Heterocyclic aromatic amines (HAA) are initiating agents of colon carcinogenesis in animals and are suspected in the aetiology of human colon cancer. In the context of prevention, it seems interesting to test possible protective compounds, such as fermented milk, against HAA food carcinogens. Male F344 rats were used in a model of HAA-induced colon carcinogenesis. The HAA, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) (ratio 1:1:1) were administered in food for a 7 week induction period, with a cumulative dose of 250 mg of the HAA, per kg body weight. Four different diets were given to four rat groups: supplemented with 20% water, 30% non-fermented milk, 30% Bifidobacterium animalis DN-173 010 fermented milk and 30% Streptococcus thermophilus DN-001 158 fermented milk. Fecal mutagenicity was quantified during the induction period. At the end of the treatment, DNA lesion levels were determined in the liver and colon using the number of 8-oxo-7,8-dihydro-2'desoxyguanosine (8-oxodGuo) oxidized bases, "3D Test" and comet assay. The metabolic activity of hepatic and colon cytochrome P450 (CYP450) 1A1 and 1A2 was also evaluated. Aberrant colon crypts were scored, 8 weeks after the last HAA treatment. The results showed that dairy products decreased the incidence of aberrant crypts in rats: 66% inhibition with the milk-supplemented diet, 96% inhibition with the B.animalis fermented milk-supplemented diet and 93% inhibition with the S.thermophilus fermented milk-supplemented diet. Intermediate biomarkers showed that there was a decrease in HAA metabolism, fecal mutagenicity and colon DNA lesions. These results demonstrate the early protective effect of milk in the carcinogenesis process. This effect being more pronounced in the case of milk fermented by lactic acid bacteria.
authors.affiliation: Food and Colon Carcinogenesis Laboratory, ISTAB, Bordeaux 1 University, 33405 Talence cedex, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Tavan
authors.forename: Chantal
authors.initials: C
authors.lastname: Cayuela
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Antoine
authors.forename: Germain
authors.initials: G
authors.lastname: Trugnan
authors.forename: Chantal
authors.initials: C
authors.lastname: Chaugier
authors.forename: Pierrette
authors.initials: P
authors.lastname: Cassand
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis; D003106:Colon / Q000378:metabolism / Q000473:pathology; D003110:Colonic Neoplasms / Q000139:chemically induced* / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects; D003611:Dairy Products / Q000382:microbiology; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D004032:Diet; D005243:Feces / Q000382:microbiology; D005285:Fermentation; D006571:Heterocyclic Compounds / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism / Q000473:pathology; D008297:Male; D008892:Milk / Q000378:metabolism; D016296:Mutagenesis / Q000187:drug effects; D051381:Rats; D011916:Rats, Inbred F344; D015430:Weight Gain
chemical_list: D014408:Biomarkers, Tumor; D006571:Heterocyclic Compounds; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine