Acupuncture improves intestinal barrier function and visceral pain in rats with irritable bowel syndrome by blocking BDNF/TrkB signaling pathway
Objective:To explore whether acupuncture can affect intestinal barrier and visceral pain of rats with irritable bowel syndrome(IBS)by regulating brain-derived neurotrophic factor(BDNF)and its downstream tyrosine kinase receptor B(TrkB),and to explore the possibility of BDNF/TrkB signaling pathway as a new target for acupuncture treatment.Methods:Sixty SD rats were ran-domly grouped into healthy group,IBS group,acupuncture group,positive control group and acupuncture+TrkB activation group,with 12 rats in each group.An IBS rat model was established,abdominal withdrawal reflex(AWR)was used to detect visceral pain of rats in each group;levels of TNF-α and IL-1β in colon of rats in each group were measured;expression levels of colonic mucosal cyto-plasmic Claudin 1(ZO-1)and occludin were measured with immunohistochemistry;expression levels of BDNF and TrkB mRNA and protein in colon of rats in each group were measured with fluorescence quantitative PCR and Western blot.Results:Compared with healthy group,colonic mucosa of rats in IBS group was damaged,expressions of ZO-1 and occludin were significantly reduced,AWR score,fecal water content,TNF-α and IL-1β contents,colonic BDNF,TrkB mRNA and BDNF protein expressions,and TrkB phos-phorylation were significantly increased(P<0.05);compared with IBS group,colon mucosa of acupuncture group and positive control group gradually recovered,expressions of ZO-1 and occludin were significantly increased,AWR score,fecal water content,TNF-α and IL-1β contents,colonic BDNF,TrkB mRNA and BDNF protein expressions,and TrkB phosphorylation were significantly re-duced(P<0.05);compared with acupuncture group,colonic mucosa of rats in acupuncture+TrkB activation group still had lesions,expressions of ZO-1 and occludin were significantly reduced,AWR score,fecal water content,TNF-α and IL-1β contents,colonic BDNF,TrkB mRNA and BDNF protein expressions,and TrkB phosphorylation were significantly increased(P<0.05).Conclusion:Acupuncture can regulate BDNF/TrkB pathway,inhibit expression of related proteins,improve intestinal barrier function,reduce vis-ceral pain,inflammation and relieve IBS.