title: Diversity of caecal bacteria is altered in interleukin-10 gene-deficient mice before and after colitis onset and when fed polyunsaturated fatty acids.
abstract: Interleukin-10 gene-deficient (Il10(-/-)) mice show a hyper-reaction to normal intestinal bacteria and develop spontaneous colitis similar to that of human Crohn's disease when raised under conventional (but not germ-free) conditions. The lack of IL10 protein in these mice leads to changes in intestinal metabolic and signalling processes. The first aim of this study was to identify changes in the bacterial community of the caeca at 7 weeks of age (preclinical colitis) and at 12 weeks of age (when clinical signs of colitis are present), and establish if there were any changes that could be associated with the mouse genotype. We have previously shown that dietary n-3 and n-6 polyunsaturated fatty acids (PUFA) have anti-inflammatory effects and affect colonic gene expression profiles in Il10(-/-) mice; therefore, we also aimed to test the effect of the n-3 PUFA eicosapentaenoic acid (EPA) and the n-6 PUFA arachidonic acid (AA) on the bacterial community of caeca in both Il10(-/-) and C57 mice fed these diets. The lower number of caecal bacteria observed before colitis (7 weeks of age) in Il10(-/-) compared to C57 mice suggests differences in the intestinal bacteria that might be associated with the genotype, and this could contribute to the development of colitis in this mouse model. The number and diversity of caecal bacteria increased after the onset of colitis (12 weeks of age). The increase in caecal Escherichia coli numbers in both inflamed Il10(-/-) and healthy C57 mice might be attributed to the dietary PUFA (especially dietary AA), and thus not be a cause of colitis development. A possible protective effect of E. coli mediated by PUFA supplementation and associated changes in the bacterial environment could be a subject for further investigation to define the mode of action of PUFA in colitis.
authors.affiliation: Institute of Food, Nutrition and Human Health, Massey University, Tennent Drive, Palmerston North 4442, New Zealand.|Food Nutrition Genomics Team, Agri-Foods & Health Section, Food & Textiles Group, AgResearch Grasslands, Tennent Drive, Palmerston North 4442, New Zealand.
authors.forename: Bianca
authors.initials: B
authors.lastname: Knoch
authors.affiliation: Plant & Food Research, Batchelar Road, Palmerston North 4442, New Zealand.
authors.forename: Katia
authors.initials: K
authors.lastname: Nones
authors.affiliation: Food Nutrition Genomics Team, Agri-Foods & Health Section, Food & Textiles Group, AgResearch Grasslands, Tennent Drive, Palmerston North 4442, New Zealand.
authors.forename: Matthew P G
authors.initials: MPG
authors.lastname: Barnett
authors.affiliation: Riddet Institute, Massey University, Tennent Drive, Palmerston North 4442, New Zealand.|Food & Textiles Group, AgResearch Grasslands, Tennent Drive, Palmerston North 4442, New Zealand.
authors.forename: Warren C
authors.initials: WC
authors.lastname: McNabb
authors.affiliation: Riddet Institute, Massey University, Tennent Drive, Palmerston North 4442, New Zealand.|Food Nutrition Genomics Team, Agri-Foods & Health Section, Food & Textiles Group, AgResearch Grasslands, Tennent Drive, Palmerston North 4442, New Zealand.
authors.forename: Nicole C
authors.initials: NC
authors.lastname: Roy
mesh_terms: D000818:Animals; D001419:Bacteria / Q000235:genetics* / Q000254:growth & development; D002432:Cecum / Q000382:microbiology*; D003092:Colitis / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis; D058645:Denaturing Gradient Gel Electrophoresis; D004032:Diet; D004195:Disease Models, Animal; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology*; D005838:Genotype; D016753:Interleukin-10 / Q000172:deficiency / Q000235:genetics*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout
chemical_list: D004269:DNA, Bacterial; D005231:Fatty Acids, Unsaturated; D016753:Interleukin-10