Effects of Bifidobacterium infantis 35624 on Post-Inflammatory Visceral Hypersensitivity in the Rat

Background Irritable bowel syndrome patients have abnormal visceral perception. Probiotic organisms may produce beneficial effects in these patients by reducing visceral hypersensitivity. Aim To investigate the effects of the probiotic organism, Bifidobacterium infantis 35624, on post-inflammatory visceral hypersensitivity in rats. Methods Colitis was induced using intracolonic administration of trinitrobenzenesulfonic acid; control rats received saline (day 0). Myeloperoxidase (MPO) levels and colonic damage scores were determined. From days 15-29, rats (n = 10/group) rats were orally dosed with 2 ml of B. infantis a parts per thousand yen 10(8) colony-forming units/ml or vehicle (MRS broth). A second series of rats (n = 10/group) was dosed in the same manner from days 15-59. The level of colonic stimulation during colorectal distension (CRD) was determined by recording a visceromotor response (VMR) to CRD at 30 mmHg pre- and post-treatment. Post-treatment samples of colonic tissue were weighed, graded for morphologic damage, and assayed for MPO levels. Results All rats were hypersensitive at day 15. On day 30, hypersensitivity to colorectal distension remained in the vehicle group, but was significantly reduced in the B. infantis group (mean VMR/10 min: vehicle = 15.4 +/- A 1.0 vs. B. infantis = 7.6 +/- A 1.0, p < 0.001). A similar, significant effect was observed at day 60. On both day 30 and day 60, tissue weight, colonic damage scores, and MPO levels resembled those of control animals. Conclusions Oral administration of Bifidobacterium infantis 35624 normalized sensitivity to colorectal distension in a rat model of post-inflammatory colonic hypersensitivity.