title: Bacterial population and innate immunity-related genes in rat gastrointestinal tract are altered by vitamin A-deficient diet.
abstract: Vitamin A and its derivatives have been shown to regulate the growth and differentiation of gastrointestinal epithelial cells; in addition, vitamin A deficiency has been convincingly shown to be associated with increased susceptibility to infection. The gastrointestinal mucosal barrier, which is a component of the innate immune system, is considered the first line of defense, as it provides a barrier between the external environment and the internal milieu. A disturbance in the integrity of the intestinal epithelium is one of the main factors involved in increased incidence of infections during vitamin A deficiency. In this study, the effects of vitamin A deficiency on microbial ecology and the expression of genes related to the intestinal mucosa's innate immunity were examined in a rat model. Using the 16s rDNA method, we demonstrate that a vitamin A-deficient (VAD) diet increases the total amount of bacteria in the gastrointestinal tract and alters the intestinal microflora. Results show a decrease in the relative proportion of Lactobacillus spp. and the simultaneous appearance of Escherichia coli strains. Lack of vitamin A significantly changed mucin (MUC) dynamics, as reflected by the enlarged goblet-cell "cup" area relative to controls; decreased MUC2 mRNA expression in the jejunum, ileum and colon of VAD rats and increased MUC3 mRNA expression in the ileum and colon of these rats. In addition, vitamin A deficiency down-regulated defensin 6 mRNA expression while up-regulating toll-like receptors 2 and 5 mRNA expressions. The current study indicates that vitamin A deficiency interferes with the integrity of the gastrointestinal mucosal barrier.
authors.affiliation: Department of Animal Science, The Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
authors.forename: Einat
authors.initials: E
authors.lastname: Amit-Romach
authors.forename: Zehava
authors.initials: Z
authors.lastname: Uni
authors.forename: Shira
authors.initials: S
authors.lastname: Cheled
authors.forename: Zipi
authors.initials: Z
authors.lastname: Berkovich
authors.forename: Ram
authors.initials: R
authors.lastname: Reifen
mesh_terms: D000821:Animal Feed; D000818:Animals; D001424:Bacterial Infections / Q000178:diet therapy*; D004032:Diet; D004195:Disease Models, Animal; D004926:Escherichia coli / Q000378:metabolism*; D041981:Gastrointestinal Tract / Q000382:microbiology* / Q000473:pathology*; D007113:Immunity, Innate; D007413:Intestinal Mucosa / Q000382:microbiology* / Q000473:pathology*; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014802:Vitamin A Deficiency / Q000150:complications* / Q000473:pathology
chemical_list: D012333:RNA, Messenger; D012336:RNA, Ribosomal, 16S