Stress disrupts the intestinal mucus barrier in rats via mucin O-glycosylation shift: prevention by probiotic treatment

Background: Despite evidence of intestinal epithelial barrier impairment and visceral hypersensitivity in IBS patients and IBS-like models, structural and physical changes in the mucus layer in this condition remain poorly understood. Aim: Using a water avoidance stress (WAS) model, we aimed at evaluating in ileum and colon whether (i) WAS modified gut permeability, visceral sensitivity, mucin expression, biochemical structure of O-glycans and related mucus physical properties, (ii)L. farcimin- is treatment prevented these alterations. Methods: Wistar rats received orally L. farciminis (an adhesion marker) or vehicle for 14 days. At day 10, they were submitted either to sham or 4-day WAS. Intestinal paracellular permeability and visceral sensi- tivity were measured in vivo . The number of goblet cells and Muc2 expression were evaluated by histology and immunohistochemistry, respectively. Mucosal adhesion of L. farciminis was determined ex situ . The mucin O-glycosylation profile was obtained by mass spectrom- etry. Surface imaging of intestinal mucus was performed at nanoscale by Atomic Force Microscopy. Results: WAS induced gut hyperpermeability and vis- ceral hypersensitivity but did not modify either the number of intestinal goblet cells or Muc2 expression