Published online Sep 28, 2019. doi: 10.3748/wjg.v25.i36.5469
Peer-review started: July 10, 2019
First decision: August 5, 2019
Revised: August 17, 2019
Accepted: August 24, 2019
Article in press: August 24, 2019
Published online: September 28, 2019
Irritable bowel syndrome (IBS) affects 7% to 21% of the general population. It is a chronic diseases characterized by abnormal visceral sensitivity and low-grade inflammation. The role of Clostridium butyricum (C. butyricum) in reducing intestinal low-grade inflammation via immune pathways has been well defined. However, the mechanism has not been clearly elucidated.
To test the hypothesis that the function of dendritic cells (DCs) changes in the development of IBS and to understand the regulation of DCs after C. butyricum intervention.
We aimed to investigate the mechanism of DCs in the development of IBS in a mice model and to understand the regulation of DCs after C. butyricum intervention.
An IBS animal model was established using C57BL/6 mice, and C. butyricum was continuously administered via the intragastric route to simulate different intestinal immune states. Intestinal visceral hypersensitivity and histopathology were assessed using the abdominal withdrawal reflex test and hematoxylin & eosin staining, respectively. The expression of proinflammatory cytokines (IL-1β and IL-6) and TIM3 was analyzed by Western blot analysis and real-time PCR. The flow cytometry was applied to analyze the quantity, function, and membrane molecule TIM3 of the LPDCs. The regulatory effect of C. butyricum was verified in BMDCs by in vitro experiments.
We found that the IBS mouse model has abundant expression of IL-1β, IL-6, and CD11C+CD80+ and CD11c+TIM3+ LPDCs compared with the control group. Further investigation showed that probiotic C. butyricum reduced the expression of cytokines (IL-1β and IL-6). The amount and function of LPDCs and the membrane molecule TIM3 of the LPDCs were decreased with the alleviation of the intestinal inflammatory response.
This study demonstrated that C. butyricum could induce the expression of various pro-inflammatory cytokines via regulating the amount and the functional status of LPDCs in the intestinal mucosa of mice with IBS.
This research not only provides an in-depth understanding of the local immune response mechanism in intestinal mucosa of IBS humans, but also provides a new perspective for the application of probiotic C. butyricum in the treatment of IBS.