Effect of probiotics on visceral pain threshold in an experimental model of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic functional disorder characterized by abdominal pain and abnormal bowel function. Probiotics are used in clinical practice to treat bowel movement disturbances in IBS patients. However, it is not clear if probiotics are useful for treatment of the abdominal pain associated with visceral hypersensitivity. The aim of this study was to investigate the effect and mechanism of action of a probiotic bacterium, Streptococcus faecalis 129 BIO 3B (SF3B) on visceral pain threshold using a 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced rat visceral hypersensitivity model. In TNBStreated rats, a decrease in the visceral pain threshold of the distal colon was observed, and improvement in the threshold reduction was observed by repeated oral administration of SF3B. SF3B dose-dependently suppressed the degranulation of rat peritoneal mast cells induced by compound 48/80. These results suggest that oral administration of SF3B may prevent the abdominal pain associated with colonic pain threshold by inhibiting degranulation of mast cells in the distal colon of IBS patients.