title: Probiotics prevent bacterial translocation and improve intestinal barrier function in rats following chronic psychological stress.
abstract: OBJECTIVE
  Chronic psychological stress, including water avoidance stress (WAS), induces intestinal mucosal barrier dysfunction and impairs mucosal defences against luminal bacteria. The aim of this study was to determine the ability of a defined probiotic regimen to prevent WAS induced intestinal pathophysiology.
  
  
  METHODS
  Male rats were subjected to either WAS or sham stress for one hour per day for 10 consecutive days. Additional animals received seven days of Lactobacillus helveticus and L rhamnosus in the drinking water prior to stress and remained on these probiotics for the duration of the study. Rats were then sacrificed, intestinal segments assessed in Ussing chambers, and mesenteric lymph nodes cultured to determine bacterial translocation.
  
  
  RESULTS
  All animals remained healthy for the duration of the study. Chronic WAS induced excess ion secretion (elevated baseline short circuit current) and barrier dysfunction (increased conductance) in both the ileum and colon, associated with increased bacterial adhesion and penetration into surface epithelial cells. Approximately 70% of rats subjected to WAS had bacterial translocation to mesenteric lymph nodes while there was no bacterial translocation in controls. Probiotic pretreatment alone had no effect on intestinal barrier function. However, WAS induced increased ileal short circuit current was reduced with probiotics whereas there was no impact on altered conductance. Pretreatment of animals with probiotics also completely abrogated WAS induced bacterial adhesion and prevented translocation of bacteria to mesenteric lymph nodes.
  
  
  CONCLUSIONS
  These findings indicate that probiotics can prevent chronic stress induced intestinal abnormalities and, thereby, exert beneficial effects in the intestinal tract.
authors.affiliation: Division of Gastroenterology and Nutrition, Room 8409, Hospital for Sick Children, 555 University Ave, Toronto, Ontario, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Zareie
authors.forename: K
authors.initials: K
authors.lastname: Johnson-Henry
authors.forename: J
authors.initials: J
authors.lastname: Jury
authors.forename: P-C
authors.initials: PC
authors.lastname: Yang
authors.forename: B-Y
authors.initials: BY
authors.lastname: Ngan
authors.forename: D M
authors.initials: DM
authors.lastname: McKay
authors.forename: J D
authors.initials: JD
authors.lastname: Soderholm
authors.forename: M H
authors.initials: MH
authors.lastname: Perdue
authors.forename: P M
authors.initials: PM
authors.lastname: Sherman
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion / Q000187:drug effects; D018988:Bacterial Translocation / Q000187:drug effects*; D002908:Chronic Disease; D020895:Enterocytes / Q000382:microbiology / Q000648:ultrastructure; D007408:Intestinal Absorption / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000382:microbiology / Q000648:ultrastructure; D007778:Lactobacillus / Q000502:physiology; D008198:Lymph Nodes / Q000382:microbiology; D008297:Male; D008643:Mesentery; D008854:Microscopy, Electron; D010539:Permeability / Q000187:drug effects; D019936:Probiotics / Q000494:pharmacology*; D051381:Rats; D011914:Rats, Inbred BN; D013315:Stress, Psychological / Q000382:microbiology / Q000473:pathology / Q000503:physiopathology*