Effect of E-coli Nissle 1917 on post-inflammatory visceral sensory function in a rat model

Objective: Visceral hyperalgesia (VH) plays a key role for the manifestation of functional gastrointestinal (GI) disorders. In a subgroup of patients, the initial manifestation is preceded by GI inflammation. Recent studies have demonstrated an improvement of inflammation and symptoms during treatment with Escherichia coli Nissle 1917 (EcN). Aim: We aimed to characterize the effects of EcN on visceral sensitivity in a rat model of post-inflammatory VH. Methods: Male Lewis rats underwent colorectal instillation of trinitrobenzenesulphonic acid (TNBS) plus an equal amount of ethanol (test group) or physiological saline solution (control group). After 28, 35 and 42 days, standardized colorectal distensions were performed and the visceromotor reflex (VMR) of abdominal wall muscles was quantified by electromyographic recording. From day 28 onwards, EcN was administered in drinking water. Results: After TNBS, a significant increase of VMR was observed compared with saline controls over all study days. Administration of EcN reduced the TNBS-induced hyperalgesia [EcN: 863 +/- 125 mu V vs placebo: 1258 +/- 157 mu V (P < 0.05)] at day 35, while there were no significant alterations at any other study day. Conclusion: The EcN administration caused a significant reduction of VH. Whether EcN might play a role in the treatment of post-infectious functional bowel disorders remains to be investigated in further studies.