Mechanism of QingHuaZhiXie Prescription Regulating TLR4-IECs Pathway in the Intervention of Diarrhea Predominant Irritable Bowel Syndrome

To investigate the effect and mechanism of QingHuaZhiXie prescription on diarrhea predominant irritable bowel syndrome (D-IBS), animal models of rats were used in this study. 48 rats were randomly divided into 6 groups, containing one control group, one animal model group (D-IBS group), and four drug intervention groups (low, medium, and high dosage of QingHuaZhiXie prescription and trimebutine maleate intervention group). Abdominal withdrawal reflex (AWR) and Bristol stool form scale were recorded; the expression levels of inflammatory factors (TNF-α and IFN-γ), pathway proteins TLR4, MyD88, NF-κB, and key proteins of tight junction between intestinal epithelial cells (IECs) were detected; the microstructure of intestinal mucosal was observed by hematoxylin and eosin (H&E) staining; MPO activity was detected with immunohistochemical analysis to reflect the inflammation of tissues. Results show that QingHuaZhiXie prescription reduced diarrhea index and intestinal hypersensitivity and intestinal tissue integrity after intervention. MPO activity in QingHuaZhiXie prescription-treated rats was significantly lower relative to their model group. The expression levels of inflammatory factors and TLR4/MyD88/NF-κB pathway proteins were repressed, and the protein levels of occludin and claudin-1 increased. Meanwhile, this study also found that the remission effect of QingHuaZhiXie prescription on D-IBS increased with its dosage increase. Hence, as a therapeutic prescription for D-IBS, QingHuaZhiXie prescription could relieve D-IBS symptoms through balancing the inflammatory factors expression by inhibiting the TLR4/MyD88/NF-κB pathway and maintaining the function and structure of IECs by improving the protein levels of JAM, occludin, claudin-1, and ZO-1.

Ginger relieves intestinal hypersensitivity of diarrhea predominant irritable bowel syndrome by inhibiting proinflammatory reaction

Background Ginger or ginger extracts have been used in traditional medicine relieve pain caused by diarrhea predominant irritable bowel syndrome (IBS-D), but few data exists about its effectiveness. This present study was to validate the effect of ginger on visceral pain, and to further explore the possible underlying mechanism by which ginger is used to relieve IBS-D intestinal hypersensitivity. Methods First, the IBS-D rat model was established by chemical stimulation and acute and chronic pressure stimulation. Then, different dose of ginger were administrated to IBS-D rats and evaluate the defecation frequency, fecal water content (FWC) and abdominal withdrawal reflex (AWR) scores in IBS-D rats. Further, the IBS-D rats were sacrificed to collecte the colonic tissues to evaluate the effect of ginger administration on its pathology and changes of pro-inflammatory factors, and changes of NF-κB pathway. Second, the ginger was taken to HPLC analysis and 6-gingerol was choosen to further experiment. Then, IBS-D rats were treated with different dose of 6-gingerol, and the behavioral evaluation were to evaluate the effect of 6-gingerol on IBS-D rats. Further, colonic epithelial cells (CECs) were collectted and to evaluate the effect of 6-gingerol on the expression of inflammatory factors and changes of NF-κB pathway. Results The IBS-D rat model was successfully established by chemical stimulation and acute and chronic pressure stimulation. And ginger treatment significantly reduced the defecation frequency, fecal water content and AWR scores in IBS-D rats. Histopathological analysis showed that ginger treatment can significantly reduce colonic edema and promote the recovery of inflammation in IBS-D rats, and the effect is equivalent to rifaximin. Elisa and RT-qPCR showed that ginger inhibited the expression of proinflammatory factors (TNF-α, IL-6, iNOS) in IBS-D rats. Western blot showed IkBα was up-regulated while p-p65 was inhibited under ginger treatment. HPLC analysis showed that 6-gingerol was the main component of ginger, which could improve clinical symptoms in IBS-D rats. Western blot and RT-qPCR showed that 6-gingerol inhibited the expression of proinflammatory factors (TNF-α, IL-6, iNOS) in CECs, and inhibition of IκBα degradation and phosphorylation of p65 involved in NF-κB pathway. Conclusion Ginger and ginger extract could relieve intestinal hypersensitivity of IBS-D by inhibiting proinflammatory response.

Effects of Deoxyschisandrin on Visceral Sensitivity of Mice with Inflammatory Bowel Disease

The aims of this study were to build an IBD mouse model and further to observe the effects of deoxyschisandrin on IBD and visceral sensitivity and to evaluate the relevance of brain-derived neurotrophic factor (BDNF) to intestinal hypersensitivity of IBD mice. The results showed that deoxyschisandrin could depress the contraction of isolated smooth muscle, modulate gastrointestinal function, and efficiently decrease the disease activity index (DAI) of IBD mice, which proved that deoxyschisandrin had antidiarrheal effects on the animals. In the colorectal distention (CRD) experiment, visceral sensibility was increased in the model group. However, abdominal withdrawal reflex (AWR) scores were decreased after deoxyschisandrin intervention, indicating that deoxyschisandrin could reduce the visceral hypersensitivity of IBD mice. Both IHC observation and western blotting analysis showed that BDNF protein expression increased evidently in colon of IBD mice. After the intervention of deoxyschisandrin, colon mucosa BDNF protein expression in IBD mice decreased, indicating that deoxyschisandrin could decrease mouse intestinal sensitivity by reducing colon mucosa BDNF expression. In conclusion, deoxyschisandrin possessed antidiarrheal effects and visceral hypersensitivity inhibitory effects in the mice with IBD induced by TNBS, which was related to the reduction in BDNF expression in the colon.

The Transient Receptor Potential Vanilloid 4 Agonist RN-1747 Inhibits the Calcium Response to Histamine

Background: Sensitization of transient receptor potential (TRP) cation channels probably contributes to intestinal hypersensitivity, a hallmark of gastrointestinal disorders. Histamine acting via histamine 1 receptor (H1R) to open TRP cation channels might also be involved. Method: The enterochromaffin cell line P-STS, responsive to histamine via H1R, was used as model to study possible synergism between histamine and TRP vanilloid 4 (TRPV4) pathways. Results: The TRPV4 antagonist RN-1734, but not HC-067047, inhibited the cytoplasmic calcium response to histamine in P-STS cells. However, also pre-incubation with the TRPV4 agonist RN-1747 strongly inhibited the calcium response to histamine in P-STS as well as HeLa cells. This inhibitory effect of RN-1747 was not due to its known TRP melastatin 8 (TRPM8) antagonism, as the TRPM8 antagonist RQ-00203078 showed no significant effect on the histamine-induced calcium response of P-STS or HeLa cells. Conclusion: The TRPV4 agonist RN-1747, and possibly also the structurally similar TRPV4 antagonist RN-1734, should be used with caution because of yet unidentified interference with histamine signaling via H1R.

The Enteric Nervous System in Inflammation and Pain: The Role of Proteinase-Activated Receptors

The enteric nervous system (ENS) plays a pivotal role in inflammatory and nociceptive processes. Drugs that interact with the ENS have recently raised considerable interest because of their capacity to regulate numerous aspects of the gut physiology and pathophysiology. The present article summarizes recent research on proteinases and proteinase-activated receptors (PARs) as signalling molecules in the ENS. In particular, experiments in animal models suggest that PAR2is important to neurogenic inflammation in the intestine. Moreover, PAR2agonists seem to induce intestinal hypersensitivity and hyperalgesic states, suggesting a role for this receptor in visceral pain perception. Thus, PARs, together with the proteinases that activate them, represent exciting new targets for therapeutic intervention on the ENS.