title: [Effect of dexamethasone contamination in drinking water on intestinal flora in mice].
abstract: OBJECTIVE
  To evaluate the effect of water pollution with dexamethasone on intestinal flora in mice.
  
  
  METHODS
  Twenty Balb/c mice were randomly divided into control group and low-, moderate- and high-dose dexamethasone groups. The mice in dexamethasone groups were exposed to dexamethasone sodium phosphate in drinking water at doses of 0.035, 0.225, and 2.25 ng for 36 days. The changes in behaviors, fur condition, and feces of the mice were observed daily. All the mice were sacrificed at 36 days and the tissues in the ileocecal region was collected for denaturant gradient gel electrophoresis (DGGE) of 16S rDNA V6 variable regions of microbes and sequence analysis with BLAST.
  
  
  RESULTS
  The mice in the 3 dexamethasone groups all showed aggressive behaviors. Cluster analysis of DGGE graph showed relatively stable floras in the ileocecal region in all the mice, but principal component analysis identified differences in the dominating flora among the groups. Diversity analysis of the flora revealed significantly increased amount and types of bacteria in the intestinal flora in all the 3 dexamethasone groups (P<0.05 or 0.01) compared with the control group. Sequence analysis of 16S rDNA V6 regions showed 15 common bacterial species and 2 differential species between the dexamethasone groups and the control group with changes in the type and proportion of the dominating bacterium in the dexamethasone groups. Lactobacillus colonization was detected in the control group but not in moderate- and high-dose dexamethasone groups, and Shigella species were found in the latter two groups.
  
  
  CONCLUSIONS
  Water contamination with dexamethasone can affect the nervous system of mice, cause changes in the types and amounts of intestinal bacteria and the dominating bacteria, and inhibit the colonization of probiotics in the intestinal floras to increase the risk of invasion by intestinal pathogenic bacteria.
authors.affiliation: Department of Pathgenic Biology, College of Basic Medical Sciences, Chongqing Medical University, Chongqing 400016, China. E-mail: YX_513@126.com.
authors.forename: Xi
authors.initials: X
authors.lastname: Yang
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Li
authors.forename: Dan
authors.initials: D
authors.lastname: Si
authors.forename: Zhi-Bang
authors.initials: ZB
authors.lastname: Yang
authors.forename: Zhong-Yuan
authors.initials: ZY
authors.lastname: He
authors.forename: Nan-Chen
authors.initials: NC
authors.lastname: Zhang
authors.forename: Shan-Shan
authors.initials: SS
authors.lastname: Zhang
authors.forename: Zhong-Quan
authors.initials: ZQ
authors.lastname: Shi
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification; D003907:Dexamethasone / Q000494:pharmacology*; D060766:Drinking Water / Q000737:chemistry*; D005243:Feces; D000069196:Gastrointestinal Microbiome / Q000187:drug effects*; D007778:Lactobacillus / Q000302:isolation & purification; D051379:Mice; D008807:Mice, Inbred BALB C; D019936:Probiotics; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012760:Shigella / Q000302:isolation & purification
chemical_list: D060766:Drinking Water; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D003907:Dexamethasone