title: Probiotic gut effect prevents the chronic psychological stress-induced brain activity abnormality in mice.
abstract: BACKGROUND
  A probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 combination, Probio'Stick(®) ) displays anxiolytic-like activity and reduces apoptosis in the lymbic system in animal models of depression. Based on the hypothesis that modulation of gut microbiota by this probiotic formulation has beneficial effects on brain activity in stress conditions, we report a set of probiotic-evoked physiological, cellular, and molecular events in the brain of Probio'Stick(®) pretreated mice submitted to chronic psychological stress.
  
  
  METHODS
  Water avoidance stress (WAS) was applied or not (sham). Hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS) responses to the chronic stress were assessed through plasma corticosterone and catecholamine measurements. Specific markers for neuronal activity, neurogenesis, and synaptic plasticity were used to assess brain activity. In addition, gut permeability and tight junction (TJ) proteins levels were also determinated.
  
  
  RESULTS
  We observed that a pretreatment with the probiotic formulation attenuated HPA axis and ANS activities in response to WAS, and reduced cFos expression in different brain areas but Lactobacillus salivarius (a negative control) treatment was ineffective on these parameters. Moreover, probiotic pretreatment prevented the WAS-induced decrease hippocampal neurogenesis and expression changes in hypothalamic genes involved in synaptic plasticity. These central effects were associated with restoration of TJ barrier integrity in stressed mice.
  
  
  CONCLUSIONS
  These data suggest that chronic stress-induced abnormal brain plasticity and reduction in neurogenesis can be prevented by a pretreatment with the Probio'Stick(®) formulation, suggesting that probiotics modulate neuroregulatory factors and various signaling pathways in the central nervous system involved in stress response.
authors.affiliation: Neuro-Gastroenterologie et Nutrition team, TOXALIM, UMR 1331-INRA/INP/UPS, Toulouse, France; Lallemand Health Solutions Inc., Montreal, QC, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Ait-Belgnaoui
authors.forename: A
authors.initials: A
authors.lastname: Colom
authors.forename: V
authors.initials: V
authors.lastname: Braniste
authors.forename: L
authors.initials: L
authors.lastname: Ramalho
authors.forename: A
authors.initials: A
authors.lastname: Marrot
authors.forename: C
authors.initials: C
authors.lastname: Cartier
authors.forename: E
authors.initials: E
authors.lastname: Houdeau
authors.forename: V
authors.initials: V
authors.lastname: Theodorou
authors.forename: T
authors.initials: T
authors.lastname: Tompkins
mesh_terms: D000818:Animals; D001644:Bifidobacterium; D001921:Brain / Q000378:metabolism / Q000503:physiopathology*; D002908:Chronic Disease; D041981:Gastrointestinal Tract / Q000503:physiopathology; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism; D052198:Lactobacillus helveticus; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D055495:Neurogenesis; D009473:Neuronal Plasticity / Q000235:genetics; D010913:Pituitary-Adrenal System / Q000378:metabolism; D019936:Probiotics; D013315:Stress, Psychological / Q000503:physiopathology*
keywords: brain-gut axis; chronic psychological stress; intestinal barrier; probiotics