Mechanisms of Peitu Yimu acupuncture in repairing intestinal mucosal barrier by regulating CRF/CRFR1 pathway in diarrhea-predominant irritable bowel syndrome rats. / 培土抑木针法调节CRF/CRFR1é€šè·¯ä¿®å¤è ¹æ³»åž‹è‚ æ˜“æ¿€ç»¼åˆå¾å¤§é¼ è‚ é»è†œå±éšœçš„æœºåˆ¶ç ”ç©¶.

OBJECTIVES: To investigate the effect of Peitu Yimu(strengthening spleen and soothing liver) acupuncture on intestinal mucosal barrier function and corticotropin-releasing factor (CRF)/CRF receptor 1 (CRFR1) pathway in rats with diarrhea-predominant irritable bowel syndrome (IBS-D), so as to explore its underlying mechanism in alleviating IBS-D. METHODS: Forty female SD rats were randomly divided into blank, model, electroacupuncture (EA), and agonist groups, with 10 rats in each group. Except for the blank group, rats in the other groups were given folium sennae infusion by gavage combined with chronic unpredictable mild stress to establish IBS-D model. Rats in the EA group received acupuncture at "Tianshu"(ST25) and EA at "Zusanli"(ST36) and "Taichong"(LR3) (2 Hz/15 Hz) on one side for 20 min, with the side chosen alternately every other day, for 14 days after modeling. Rats in the agonist group received acupuncture 30 min after intravenous injection of CRFR1 agonist urocortin, with the same manipulation method and time as the EA group. Before and after intervention, visceral pain threshold and stool Bristol scores were measured. Elevated plus maze test and open field test were used to detect anxiety and depression like behavior of rats. ELISA was used to detect the contents of CRF and CRFR1 in rats serum. Immunohistochemistry was used to detect the positive expressions of CRF, CRFR1, zonula occludens protein 1(ZO-1), occlusal protein(Occludin), and closure protein 1 (Claudin-1) in colon tissue. RESULTS: Compared with the blank group, the visceral pain threshold, open arm time percentage (OT%), total distance of movement in the open field test, and positive expression of ZO-1, Occludin, and Claudin-1 in colon were decreased (P<0.01, P<0.05), while Bristol stool scores, serum CRF and CRFR1 contents, and positive expressions of CRF and CRFR1 in colon were increased (P<0.01) in the model group. After intervention and compared with the model group, the visceral pain threshold, OT%, total distance of movement in the open field test, and positive expressions of ZO-1, Occludin, and Claudin-1 in colon were increased (P<0.05, P<0.01), while Bristol stool scores, serum CRF and CRFR1 contents, and positive expressions of CRF and CRFR1 in colon were decreased (P<0.01) in the EA group；the Bristol stool scores, serum CRF content, and CRF positive expression in colon were significantly decreased in the agonist group (P<0.01). CONCLUSIONS: Peitu Yimu acupuncture can significantly improve visceral hypersensitivity and anxiety-depression state in IBS-D rats. Its mechanism may be related to the inhibition of CRF/CRFR1 pathway and restoration of intestinal tight junction protein expressions.

Fructose malabsorption and fructan malabsorption are associated in patients with irritable bowel syndrome.

BACKGROUND: Food malabsorption and intolerance is implicated in gastrointestinal symptoms among patients with irritable bowel syndrome (IBS). Key triggers include fructose and fructan. Prior studies examined fructose and fructan malabsorption separately in IBS patients. None have concurrently assessed both within the same patient group. We aimed to investigate the association between fructose and fructan malabsorption in the same patients with IBS using hydrogen breath testing (HBT). METHODS: We retrospectively identified patients with IBS who underwent fructose and fructan HBTs and abstracted their results from the electronic medical record. Fructose and fructan HBTs were performed by administering a 25 g fructose solution or 10 g fructan solution, followed by breath hydrogen readings every 30 min for 3 h. Patients were positive for fructose or fructan malabsorption if breath hydrogen levels exceeded 20 ppm. RESULTS: Of 186 IBS patients, 71 (38.2%) were positive for fructose malabsorption and 91 (48.9%) were positive for fructan malabsorption. Of these patients, 42 (22.6%) were positive for fructose malabsorption and fructan malabsorption. Positive fructose HBT readings were significantly associated with positive fructan HBT readings (p = 0.0283). Patients positive for fructose malabsorption or fructan malabsorption had 1.951 times higher odds of testing positive for the other carbohydrate. CONCLUSIONS: Our results reveal a clinically significant association between fructose malabsorption and fructan malabsorption in patients with IBS. Fructan malabsorption should be assessed in patients with fructose malabsorption, and vice versa. Further studies are required to identify the mechanisms underlying our findings.

Effect of a 12-Week Walking Program Monitored by Global Physical Capacity Score (GPCS) on Circulating Cell-Free mtDNA and DNase Activity in Patients with Irritable Bowel Syndrome.

Irritable bowel syndrome (IBS) involves low-grade mucosal inflammation. Among the various approaches capable of managing the symptoms, physical activity is still under investigation. Despite its benefits, it promotes oxidative stress and inflammation. Mitochondria impacts gut disorders by releasing damage-associated molecular patterns, such as cell-free mtDNA (cf-mtDNA), which support inflammation. This study evaluated the effects of a 12-week walking program on the cf-mtDNA and DNase in 26 IBS and 17 non-IBS subjects. Pro- and anti-inflammatory cytokines were evaluated by ELISA. Digital droplet PCR was used to quantify cf-mtDNA; DNase activity was assessed using a single radial enzyme diffusion assay. PCR-RFLP was used to genotype DNASE1 rs1053874 SNP. Significantly lower IL-10 levels were found in IBS than in non-IBS individuals. Exercise reduced cf-mtDNA in non-IBS subjects but not in IBS patients. DNase activity did not correlate with the cf-mtDNA levels in IBS patients post-exercise, indicating imbalanced cf-mtDNA clearance. Different rs1053874 SNP frequencies were not found between groups. The study confirms the positive effects of regular moderate-intensity physical activity in healthy subjects and its role in cf-mtDNA release and clearance. Walking alone might not sufficiently reduce subclinical inflammation in IBS, based on imbalanced pro- and anti-inflammatory molecules. Prolonged programs are necessary to investigate their effects on inflammatory markers in IBS.

Tranilast alleviates visceral hypersensitivity and colonic hyperpermeability by suppressing NLRP3 inflammasome activation in irritable bowel syndrome rat models.

Visceral hypersensitivity resulting from compromised gut barrier with activated immune system is a key feature of irritable bowel syndrome (IBS). Corticotropin-releasing factor (CRF) and Toll-like receptor 4 (TLR4) activate proinflammatory cytokine signaling to induce these changes, which is one of the mechanisms of IBS. As activation of the NLRP3 inflammasome by lipopolysaccharide (LPS) or TLR4 leads to release interleukin (IL)-1ß, the NLRP3 inflammasome may be involved in the pathophysiology of IBS. Tranilast, an anti-allergic drug has been demonstrated to inhibit the NLRP3 inflammasome, and we evaluated the impact of tranilast on visceral hypersensitivity and colonic hyperpermeability induced by LPS or CRF (IBS rat model). Visceral pain threshold caused by colonic balloon distention was measured by monitoring abdominal muscle contractions electrophysiologically. Colonic permeability was determined by quantifying the absorbed Evans blue within the colonic tissue. Colonic protein levels of NLRP3 and IL-1ß were assessed by immunoblot or ELISA. Intragastric administration of tranilast (20-200 mg/kg) for 3 days inhibited LPS (1 mg/kg)-induced visceral hypersensitivity and colonic hyperpermeability in a dose-dependent manner. Simultaneously, tranilast also abolished these alterations induced by CRF (50 µg/kg). LPS increased colonic protein levels of NLRP3 and IL-1ß, and tranilast inhibited these changes. ß-hydroxy butyrate, an NLRP3 inhibitor, also abolished visceral hypersensitivity and colonic hyperpermeability caused by LPS. In contrast, IL-1ß induced similar GI alterations to LPS, which were not modified by tranilast. In conclusion, tranilast improved visceral pain and colonic barrier by suppression of the NLRP3 inflammasome in IBS rat models. Tranilast may be useful for IBS treating.

Multi-Omics Analysis of Gut Microbiota and Host Transcriptomics Reveal Dysregulated Immune Response and Metabolism in Young Adults with Irritable Bowel Syndrome.

The integrated dysbiosis of gut microbiota and altered host transcriptomics in irritable bowel syndrome (IBS) is yet to be known. This study investigated the associations among gut microbiota and host transcriptomics in young adults with IBS. Stool and peripheral blood samples from 20 IBS subjects and 21 healthy controls (HCs) collected at the baseline visit of an RCT were sequenced to depict the gut microbiota and transcriptomic profiles, respectively. The diversities, composition, and predicted metabolic pathways of gut microbiota significantly differed between IBS subjects and HCs. Nine genera were significantly abundant in IBS stool samples, including Akkermansia, Blautia, Coprococcus, Granulicatella, Holdemania, Oribacterium, Oscillospira, Parabacteroides, and Sutterella. There were 2264 DEGs found between IBS subjects and HCs; 768 were upregulated, and 1496 were downregulated in IBS participants compared with HCs. The enriched gene ontology included the immune system process and immune response. The pathway of antigen processing and presentation (hsa04612) in gut microbiota was also significantly different in the RNA-seq data. Akkermansia, Blautia, Holdemania, and Sutterella were significantly correlated with ANXA2P2 (upregulated, positive correlations), PCSK1N (downregulated, negative correlations), and GLTPD2 (downregulated, negative correlations). This study identified the dysregulated immune response and metabolism in IBS participants revealed by the altered gut microbiota and transcriptomic profiles.

The function of the gut microbiota-bile acid-TGR5 axis in diarrhea-predominant irritable bowel syndrome.

Imbalanced gut microbiota (GM) and abnormal fecal bile acid (BA) are thought to be the key factors for diarrhea-predominant irritable bowel syndrome (IBS-D), but the underlying mechanism remains unclear. Herein, we explore the influence of the GM-BA-Takeda G-protein-coupled receptor 5 (TGR5) axis on IBS-D. Twenty-five IBS-D patients and fifteen healthy controls were recruited to perform BA-related metabolic and metagenomic analyses. Further, the microbiota-humanized IBS-D rat model was established by fecal microbial transplantation (FMT) to investigate the GM-BA-TGR5 axis effects on the colonic barrier and visceral hypersensitivity (VH) in IBS-D. Finally, we used chenodeoxycholic acid (CDCA), an important BA screened out by metabolome, to evaluate whether it affected diarrhea and VH via the TGR5 pathway. Clinical research showed that GM associated with bile salt hydrolase (BSH) activity such as Bacteroides ovatus was markedly reduced in the GM of IBS-D, accompanied by elevated total and primary BA levels. Moreover, we found that CDCA not only was increased as the most important primary BA in IBS-D patients but also could induce VH through upregulating TGR5 in the colon and ileum of normal rats. TGR5 inhibitor could reverse the phenotype, depression-like behaviors, pathological change, and level of fecal BSH in a microbiota-humanized IBS-D rat model. Our findings proved that human-associated FMT could successfully induce the IBS-D rat model, and the imbalanced GM-BA-TGR5 axis may promote colonic mucosal barrier dysfunction and enhance VH in IBS-D. IMPORTANCE: Visceral hypersensitivity and intestinal mucosal barrier damage are important factors that cause abnormal brain-gut interaction in diarrhea-predominant irritable bowel syndrome (IBS-D). Recently, it was found that the imbalance of the gut microbiota-bile acid axis is closely related to them. Therefore, understanding the structure and function of the gut microbiota and bile acids and the underlying mechanisms by which they shape visceral hypersensitivity and mucosal barrier damage in IBS-D is critical. An examination of intestinal feces from IBS-D patients revealed that alterations in gut microbiota and bile acid metabolism underlie IBS-D and symptom onset. We also expanded beyond existing knowledge of well-studied gut microbiota and bile acid and found that Bacteroides ovatus and chenodeoxycholic acid may be potential bacteria and bile acid involved in the pathogenesis of IBS-D. Moreover, our data integration reveals the influence of the microbiota-bile acid-TGR5 axis on barrier function and visceral hypersensitivity.

Overexpression of EphB2 in the basolateral amygdala is crucial for inducing visceral pain sensitization in rats subjected to water avoidance stress.

AIMS: Basolateral amygdala (BLA), as a center for stress responses and emotional regulation, is involved in visceral hypersensitivity of irritable bowel syndrome (IBS) induced by stress. In the present study, we aimed to investigate the role of EphB2 receptor (EphB2) in BLA and explore the underlying mechanisms in this process. METHODS: Visceral hypersensitivity was induced by water avoidance stress (WAS). Elevated plus maze test, forced swimming test, and sucrose preference test were applied to assess anxiety- and depression-like behaviors. Ibotenic acid or lentivirus was used to inactivate BLA in either the induction or maintenance stage of visceral hypersensitivity. The expression of protein was determined by quantitative PCR, immunofluorescence, and western blot. RESULTS: EphB2 expression was increased in BLA in WAS rats. Inactivation of BLA or downregulation of EphB2 in BLA failed to induce visceral hypersensitivity as well as anxiety-like behaviors. However, during the maintenance stage of visceral pain, visceral hypersensitivity was only partially relieved but anxiety-like behaviors were abolished by inactivation of BLA or downregulation of EphB2 in BLA. Chronic WAS increased the expression of EphB2, N-methyl-D-aspartate receptors (NMDARs), and postsynaptic density protein (PSD95) in BLA. Downregulation of EphB2 in BLA reduced NMDARs and PSD95 expression in WAS rats. However, activation of NMDARs after the knockdown of EphB2 expression still triggered visceral hypersensitivity and anxiety-like behaviors. CONCLUSIONS: Taken together, the results suggest that EphB2 in BLA plays an essential role in inducing visceral hypersensitivity. In the maintenance stage, the involvement of EphB2 is crucial but not sufficient. The increase in EphB2 induced by WAS may enhance synaptic plasticity in BLA through upregulating NMDARs, which results in IBS-like symptoms. These findings may give insight into the treatment of IBS and related psychological distress.

Electroacupuncture Improving Intestinal Barrier Function in Rats with Irritable Bowel Syndrome Through Regulating Aquaporins.

BACKGROUND: Intestinal mucosal barrier dysfunction plays a crucial role in the pathogenesis of irritable bowel syndrome with diarrhea (IBS-D). In order to explore the mechanism of electroacupuncture (EA) treatment on intestinal mucosal barrier, this study observed the effect of EA on aquaporins (AQPs), tight junctions (TJs), NF-κB pathway and the gut microbiota in IBS-D rats. METHODS: The IBS-D model was established by acetic acid enema combined with chronic restraint method. The effects of EA on the treatment of IBS-D were examined by the abdominal withdrawal reflex score, Bristol's fecal character score, fecal water content, small intestine propulsion rate and HE staining. AQPs, TJs and inflammation-related molecular mechanisms were explored. The fecal samples were applied for 16S rRNA sequencing to assess the effect of EA intervention to the intestinal bacterial abundance. RESULTS: EA reduced intestinal sensitization, restored intestinal motility and improved inflammatory cell infiltration. Furthermore, EA improved intestinal inflammation and flora environment significantly, inhibited NF-κB signaling and inflammatory factors (IL-1ß and TNF-α). It can also increase the gene and protein expression of AQPs (AQP1, AQP3, and AQP8) and the gene levels of TJs (ZO-1 and Occludin). CONCLUSION: EA has an inhibitory effect on the NF-κB signaling pathway, and regulates the proteins of AQP1, AQP3, AQP8, and TJs to restore the balance of water metabolism and intestinal permeability in IBS-D, which also restored the function of the intestinal mucosa by regulating the intestinal flora.

Moxibustion ameliorates visceral hypersensitivity by regulating hypothalamus-spinal cord-colon axis in rats with irritable bowel syndrome with diarrhea. / 基于下丘脑-脊髓-ç»“è‚ è½´æŽ¢è®¨è‰¾ç¸æ”¹å–„è ¹æ³»åž‹è‚ æ˜“æ¿€ç»¼åˆå¾å¤§é¼ å† è„é«˜æ•æ„Ÿçš„ä½œç”¨æœºåˆ¶.

OBJECTIVES: To observe the effect of moxibustion intervention on the hypothalamus-spinal cord-colon axis of rats with irritable bowel syndrome with diarrhea (IBS-D) and explore the mechanism of moxibustion in improving visceral hypersensitivity in rats with IBS-D. METHODS: A total of 36 SD rats were randomly divided into normal, model, and moxibustion groups, with 12 rats in each group. The IBS-D model was established by maternal separation + acetic acid stimulation + chronic restraint. Rats of the moxibustion group received bilateral moxibustion on "Tianshu" (ST25) and "Shangjuxu" (ST37) for 15 min, once a day for 7 consecutive days. The body weight, loose stool rate, and minimum threshold volume of abdominal withdrawal reflex (AWR) were measured before and after moxibustion intervention, respectively. The histopathological changes in the colon tissue were observed after HE staining. The number of colonic mucosal mast cells (MCs) was measured by toluidine blue staining. The activation of MCs was determined by tryptase positive expression level and examined by immunohistochemical staining. The content, protein and mRNA expression levels and positive expression levels of corticotropin releasing factor (CRF), substance P (SP), and calcitonin gene-related peptide (CGRP) in the hypothalamus, spinal cord and colon tissues were measured by ELISA, Western blot, real-time fluorescent quantitative PCR and immunofluorescence staining, respectively. RESULTS: Compared with the normal group, the loose stool rate was increased (P<0.01)；the body weight and minimum threshold volume of AWR were decreased (P<0.01)；the inflammatory infiltration of colon tissues was obvious；the number of MCs and positive expression level of tryptase in the colon tissue were increased (P<0.01)；the contents, positive expression le-vels, protein and mRNA expression levels of CRF, SP and CGRP in the hypothalamus, spinal cord and colon tissues were increased (P<0.01, P<0.05) in the model group. After the intervention, compared with the model group, all these indicators showed opposite trends (P<0.01, P<0.05) in the moxibustion group. CONCLUSIONS: Moxibustion can improve visceral hypersensitivity in rats with IBS-D, and its mechanism may be related to regulating the hypothalamic-spinal-colon axis to reduce the release of CRF, SP and CGRP, and thus to inhibite MC in colon tissue.

Paraventricular thalamus-insular cortex circuit mediates colorectal visceral pain induced by neonatal colonic inflammation in mice.

AIMS: Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder, but its pathogenesis remains incompletely understood, particularly the involvements of central nervous system sensitization in colorectal visceral pain. Our study was to investigate whether the paraventricular thalamus (PVT) projected to the insular cortex (IC) to regulate colorectal visceral pain in neonatal colonic inflammation (NCI) mice and underlying mechanisms. METHODS: We applied optogenetic, chemogenetic, or pharmacological approaches to manipulate the glutamatergicPVT-IC pathway. Fiber photometry was used to assess neuronal activity. Electromyography activities in response to colorectal distension (CRD) were measured to evaluate the colorectal visceral pain. RESULTS: NCI enhanced c-Fos expression and calcium activity upon CRD in the ICGlu, and optogenetic manipulation of them altered colorectal visceral pain responses accordingly. Viral tracing indicated that the PVTGlu projected to the ICGlu. Optogenetic manipulation of PVTGlu changed colorectal visceral pain responses. Furthermore, selective optogenetic modulation of PVT projections in the IC influenced colorectal visceral pain, which was reversed by chemogenetic manipulation of downstream ICGlu. CONCLUSIONS: This study identified a novel PVT-IC neural circuit playing a critical role in colorectal visceral pain in a mouse model of IBS.

Potential effects of sodium hyaluronate on constipation-predominant irritable bowel syndrome.

Treatment strategies for constipation-predominant irritable bowel syndrome (IBS-C) continue to improve. However, effective drugs are still lacking. Herein, we explored whether sodium hyaluronate (SH) could be used to treat IBS-C. The effects of SH with different molecular weights were compared in a rat model of IBS-C. Low-molecular-weight SH (LMW-SH, 5 âˆ¼ 10 kDa), medium-molecular-weight SH (MMW-SH, 200 âˆ¼ 400 kDa), and high-molecular-weight SH (HMW-SH, 1300 âˆ¼ 1500 kDa) were screened for efficacy in IBS-C using the following indicators: body weight, number of fecal pellets, fecal moisture, visceral hypersensitivity, and gastrointestinal transit rate. H-HMW-SH was the most effective in improving IBS-C symptoms. The ELISA kits indicated that H-HMW-SH reduced the levels of pro-inflammatory cytokines IL-1ß, IL-18, and TNF-α in IBS-C rats. In addition, both western blot and immunofluorescence analyses showed that H-HMW-SH increased the protein expressions of claudin-1, occludin and zonula occludens-1. Furthermore, H-HMW-SH restored the balance of intestinal flora in different intestinal contents (duodenum, jejunum, ileum, and colon) and feces of rats with IBS-C. Overall, our study illustrates the therapeutic potential of H-HMW-SH in the treatment of IBS-C.

Epithelial Barrier Dysfunction in Diarrhea-Predominant Irritable Bowel Syndrome (IBS-D) via Downregulation of Claudin-1.

BACKGROUND: In patients with diarrhea-predominant irritable bowel syndrome (IBS-D), the diarrheal mechanisms are largely unknown, and they were examined in this study on colon biopsies. METHODS: Electrophysiological measurements were used for monitoring functional changes in the diarrheic colon specimens. In parallel, tight junction protein expression was analyzed by Western blot and confocal laser-scanning microscopy, and signaling pathway analysis was performed using RNA sequencing and bioinformatics. RESULTS: Epithelial resistance was decreased, indicating an epithelial leak flux diarrheal mechanism with a molecular correlate of decreased claudin-1 expression, while induction of active anion secretion and impairment of active sodium absorption via the epithelial sodium channel, ENaC, were not detected. The pathway analysis revealed activation of barrier-affecting cytokines TNF-α, IFN-γ, IL-1ß and IL-4. CONCLUSIONS: Barrier dysfunction as a result of epithelial tight junction changes plays a role in IBS-D as a pathomechanism inducing a leak flux type of diarrhea.

[Linderae Radix water extract treats diarrhea-predominant irritable bowel syndrome in rats: a serum metabolomics study].

This study aims to investigate the mechanism of Linderae Radix water extract(LRWE) in the prevention and treatment of diarrhea-predominant irritable bowel syndrome(IBS-D) based on serum metabolomics. Eighteen 2-week-old male SD rats were randomized into control, IBS-D model, and LRWE groups. The rats in other groups except the control group received gavage of senna concentrate combined with restraint stress for the modeling of IBS-D. The rats in the LRWE group were administrated with LRWE(5.4 g·kg~(-1)) by gavage, and those in the control and IBS-D model groups with an equal volume of distilled water for a total of 14 days. The visceral sensitivity was evaluated by the abdominal withdrawal reflex(AWR) score, and the degree of diarrhea was assessed by the fecal water content(FWC). The morphological changes of the colon and the morphology and number of goblet cells were observed by hematoxylin-eosin(HE) and periodic acid-schiff(PAS) staining, respectively. Ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) was used for the screening of the potential biomarkers in the rat serum and their related metabolic pathways. The results showed that LRWE reduced the AWR score, decreased FWC, and alleviated visceral sensitivity and diarrhea symptoms in IBS-D rats. HE and PAS staining showed that LRWE mitigated low-grade intestinal inflammation and increased the number of mature secretory goblet cells in the colonic epithelium of IBS-D rats. A total of 25 potential biomarkers of LRWE in treating IBS-D were screened out in this study, which were mainly involved in riboflavin, tryptophan, glycine, serine and threonine metabolism, glyoxylate and dicarboxylate metabolism, and cysteine and methionine metabolism. The regulatory effects were the most significant on the riboflavin and tryptophan metabolism pathways. LRWE may alleviate the visceral hypersensitivity by promoting energy metabolism and amino acid metabolism, enhancing intestinal barrier function, and improving intestinal immune function in IBS-D rats.

Effect of acupuncture on the expression of neuropeptides and related inflammatory factors in rats with diarrhea-predominant irritable bowel syndrome. / é’ˆåˆºå¯¹è ¹æ³»åž‹è‚ æ˜“æ¿€ç»¼åˆå¾å¤§é¼ è„‘è‚ è‚½åŠç›¸å ³ç‚Žæ€§å› å­è¡¨è¾¾çš„å½±å“.

OBJECTIVES: To observe the effect of acupuncture on the expressions of neuropeptides and related inflammatory factors in rats with diarrhea-predominant irritable bowel syndrome(IBS-D), so as to explore the mechanism of acupuncture in the treatment of IBS-D. METHODS: Male Wistar rats were randomly divided into blank group, model group, medication group, and acupuncture group, with 6 rats in each group. Except for the blank group, the other groups were subjected to 14-day "acetic acid enema + restraint stress" to establish the IBS-D rat model. After successful modeling, the medication group received gavage of pinaverium bromide(15 mg/kg) once a day, and the acupuncture group received acupuncture at "Baihui"(GV20) and bilateral "Tianshu"(ST25), "Shangjuxu"(ST37), "Zusanli"(ST36), and "Taichong"(LR3) for 20 min every day, both groups were treated continuously for 14 days. The general state of the rats in each group was observed, and the body weight of the rats was measured. The open-field experiment was conducted to measure the horizontal and vertical movements, and the number of fecal pellets of rats. The histopathological morphology of hypothalamus and colon of rats was observed by HE staining. Toluidine blue staining was used to observe and count the mast cells(MCs) in the colon tissue of rats. ELISA was used to detect the serum contents of tumor necrosis factor-α(TNF-α) and interleukin(IL)-10. Real-time fluorescence quantitative PCR was performed to detect the mRNA expressions of calcitonin gene-related peptide(CGRP) in the hypothalamus and colon tissue. Western blot was used to detect the expressions of corticotropin-releasing factor(CRF) in the hypothalamus and colon tissue. RESULTS: HE staining showed that there was inflammatory cell infiltration in the lamina propria of colon in the model group, and it was reduced in the other groups. Compared with the blank group, the model group showed significantly decreased body weight, decreased walking distance and upright times in open field experiment, decreased serum IL-10 contents(P<0.05, P<0.01), increased fecal pellet number (P<0.01), increased MC number in the colon tissue, serum TNF-α contents, and CGRP mRNA expressions and CRF expressions in the hypothalamus and colon tissue(P<0.01). Compared with the model group, both medication and acupuncture groups showed significantly increased body weight, walking distance and upright times in the open-field experiment, and serum IL-10 contents(P<0.01, P<0.05), significantly decreased fecal pellet number (P<0.05), significantly decreased MC number in the colon tissue, serum TNF-α contents, and CGRP mRNA expressions in the hypothalamus and colon tissue(P<0.01)；at the same time, the acupuncture group showed significantly decreased CRF expressions in the hypothalamus and colon tissue(P<0.01, P<0.05). There was no significant difference in the above indicators between the medication group and the acupuncture group. CONCLUSIONS: Acupuncture can improve the general and emotional state, inflammatory response, and neuropeptide expression in rats with IBS-D, and alleviate the symptoms of IBS-D, which may be related to the regulation of neuropeptides and inflammatory factors levels.

NGF/PI3K/TRPV1 pathway mediates the regulation of visceral pain by acupuncture at "Shangjuxu" (ST37) in irritable bowel syndrome rats with chronic visceral hyperalgesia. / NGF/PI3K/TRPV1通路介导针刺"上巨虚"è°ƒèŠ‚è‚ æ˜“æ¿€ç»¼åˆå¾æ ¢æ€§å† è„ç—›æ•æ¨¡åž‹å¤§é¼ å† è„ç—›.

OBJECTIVES: To investigate the effect of manual acupuncture at "Shangjuxu"(ST37) on nerve growth factor(NGF)/phosphatidylinositol 3-kinase(PI3K)/transient receptor potential vanilloid 1(TRPV1) signaling pathway in rats with chronic visceral hyperalgesia of irritable bowel syndrome (IBS), so as to explore its underlying mechanism in treating IBS chronic visceral hyperalgesia. METHODS: IBS chronic visceral hyperalgesia model was established by colorectal dilation stimulation for 2 weeks for SD pups at 8 d after birth, which were fed until 8-week age after the stimulation. Then the verified successfully modeled adult rats were randomly divided into model, Shangjuxu, and non-acupoint groups, with 6 rats in each group, and 6 unmodeled rats were selected as normal group. On the next day of model evaluation, rats in the Shangjuxu group received acupuncture at right ST37 while rats in the non-acupoint group received acupuncture at the non-meridian and non-acupoint point in the right hypochondrium, both for 15 min, with manual twisting of mild reinforcing and reducing performed for 30 s at an interval of 5 min, once a day, for a total of 7 d. Abdominal withdrawal reflex(AWR) score was used to evaluate the degree of chronic visceral pain in rats. Western blot and real-time fluorescence quantitative PCR were used to detect the colonic protein and mRNA expressions of NGF, tropomyosin receptor kinase A (TrkA), PI3K and TRPV1. The positive expressions of PI3K and TRPV1 proteins in the colon of rats were detected by immunohistochemistry method. RESULTS: Compared with the normal group, AWR scores corresponding to 4 pressure levels of 20, 40, 60 and 80 mm Hg, mRNA and protein expressions of NGF, TrkA, PI3K and TRPV1 in colon tissue, and positive expressions of PI3K and TRPV1 in colon tissue were significantly increased(P<0.05) in the model group. After intervention, compared with the model group, rats in the Shangjuxu group had reduced AWR scores corresponding to 4 pressure levels of 20, 40, 60 and 80 mm Hg, lower colonic mRNA and protein expressions of NGF, TrkA, PI3K and TRPV1, and decreased positive expressions of PI3K and TRPV1 in colon tissue(P<0.05), while there were no significant differences in the above indexes of the non-acupoint group. CONCLUSIONS: Manual acupuncture at ST37 can alleviate IBS chronic visceral hyperalgesia in rat and its analgesic effect may be related to regulating NGF/PI3K/TRPV1 signaling pathway.

Chlorogenic Acid Ameliorates Post-Infectious Irritable Bowel Syndrome by Regulating Extracellular Vesicles of Gut Microbes.

Post-infectious irritable bowel syndrome (PI-IBS) occurs after acute infectious diarrhea, and dysbiosis can be involved in its pathogenesis. Here, the role of chlorogenic acid (CGA) is investigated, a natural compound with several pharmacological properties, in alleviating PI-IBS in rats. It is elucidated that the gut microbiota plays a key role in PI-IBS pathogenesis and that rectal administration of CGA alleviated PI-IBS by modulating the gut microbiota and its metabolites. CGA supplementation significantly increased fecal Bacteroides acidifaciens abundance and glycine levels. Glycine structurally altered B. acidifaciens extracellular vesicles (EVs) and enriched functional proteins in the EVs; glycine-induced EVs alleviated PI-IBS by reducing inflammation and hypersensitivity of the intestinal viscera and maintaining mucosal barrier function. Moreover, B. acidifaciens EVs are enriched in the brain tissue. Thus, CGA mediates the mitigation of PI-IBS through the gut microbiota and its metabolites. This study proposes a novel mechanism of signal exchange between the gut microenvironment and the host.

The Role of Ion Channels in Functional Gastrointestinal Disorders (FGID): Evidence of Channelopathies and Potential Avenues for Future Research and Therapeutic Targets.

Several gastrointestinal (GI) tract abnormalities, including visceral hypersensitivity, motility, and intestinal permeability alterations, have been implicated in functional GI disorders (FGIDs). Ion channels play a crucial role in all the functions mentioned above. Hormones and natural molecules modulate these channels and represent targets of drugs and bacterial toxins. Mutations and abnormal functional expression of ion channel subunits can lead to diseases called channelopathies. These channelopathies in gastroenterology are gaining a strong interest, and the evidence of co-relationships is increasing. In this review, we describe the correlation status between channelopathies and FGIDs. Different findings are available. Among others, mutations in the ABCC7/CFTR gene have been described as a cause of constipation and diarrhea. Mutations of the SCN5A gene are instead associated with irritable bowel syndrome. In contrast, mutations of the TRPV1 and TRPA genes of the transient receptor potential (TRP) superfamily manifest hypersensitivity and visceral pain in sensory nerves. Recently, mice and humans affected by Cantu syndrome (CS), which is associated with the mutations of the KCNJ8 and ABCC9 genes encoding for the Kir6.1 and SUR2 subunits, showed dysfunction of contractility throughout the intestine and death in the mice after the weaning on solid food. The discovery of a correlation between channelopathies and FIGD opens new avenues for discovering new direct drug targets for specific channelopathies, leading to significant implications for diagnosing and treating functional GI diseases.

Effects of FODMAPs and Gluten on Gut Microbiota and Their Association with the Metabolome in Irritable Bowel Syndrome: A Double-Blind, Randomized, Cross-Over Intervention Study.

BACKGROUND: A mechanistic understanding of the effects of dietary treatment in irritable bowel syndrome (IBS) is lacking. Our aim was therefore to investigate how fermentable oligo- di-, monosaccharides, and polyols (FODMAPs) and gluten affected gut microbiota and circulating metabolite profiles, as well as to investigate potential links between gut microbiota, metabolites, and IBS symptoms. METHODS: We used data from a double-blind, randomized, crossover study with week-long provocations of FODMAPs, gluten, and placebo in participants with IBS. To study the effects of the provocations on fecal microbiota, fecal and plasma short-chain fatty acids, the untargeted plasma metabolome, and IBS symptoms, we used Random Forest, linear mixed model and Spearman correlation analysis. RESULTS: FODMAPs increased fecal saccharolytic bacteria, plasma phenolic-derived metabolites, 3-indolepropionate, and decreased isobutyrate and bile acids. Gluten decreased fecal isovalerate and altered carnitine derivatives, CoA, and fatty acids in plasma. For FODMAPs, modest correlations were observed between microbiota and phenolic-derived metabolites and 3-indolepropionate, previously associated with improved metabolic health, and reduced inflammation. Correlations between molecular data and IBS symptoms were weak. CONCLUSIONS: FODMAPs, but not gluten, altered microbiota composition and correlated with phenolic-derived metabolites and 3-indolepropionate, with only weak associations with IBS symptoms. Thus, the minor effect of FODMAPs on IBS symptoms must be weighed against the effect on microbiota and metabolites related to positive health factors.

Cannabidiol-Decorated Berberine-Loaded Microemulsions Improve IBS-D Therapy Through Ketogenic Diet-Induced Cannabidiol Receptors Overexpression.

Background: Berberine (BR) shows promise as a candidate for treating irritable bowel syndrome with diarrhea (IBS-D). However, the undesired physicochemical properties and poor oral absorption limit its clinical translation. A ketogenic diet (KD) can induce intestinal overexpression of cannabidiol (CB) receptors, which may offer a potential target for IBS-D-specific delivery of BR. Methods: The microemulsions loaded with BR and decorated with cannabidiol (CBD/BR-MEs) were developed through a one-step emulsion method. The pharmaceutical behaviors of the CBD/BR-MEs were measured using dynamic light scattering and high-performance liquid chromatography. The efficacy of the anti-IBS-D therapy was evaluated by assessing fecal water content, Bristol score, and AWR score. The intestinal permeability were assessed through immunofluorescent staining of CB1 and ZO-1, respectively. The signaling of CREB/BDNF/c-Fos was also studied along with immunofluorescent and immunohistochemical examination of brain sections. Results: The CBD/BR-MEs, which had a particle size of approximately 30 nm and a surface density of 2% (wt%) CBD, achieved greater than 80% (wt%) encapsulation efficiency of BR. The pharmacokinetics performance of CBD/BR-MEs was significantly improved in the KD-fed IBS-D rats than the standard diet-fed ones, which is highly related to intestinal expression of CB1 receptors. The treatment with CBD/BR-MEs and KD exhibited evident comprehensive advantages over the other groups in terms of anti-IBS-D efficacy. CBD/BR-MEs and KD synergistically decreased intestinal permeability. Moreover, the treatment with CBD/BR-MEs and KD not only blocked the CREB/BDNF/c-Fos signaling in the brain but also decreased the levels of neurotrophic factors, neurotransmitters, and inflammatory cytokines in the serum of IBS-D model rats. Conclusion: Such a design represents the first attempt at IBS-D-targeted drug delivery for improved oral absorption and efficacy through KD-induced target exposure, which holds promising potential for the treatment of IBS-D.

Therapeutic effects of paeoniflorin on irritable bowel syndrome in rats.

BACKGROUND: Irritable bowel syndrome (IBS) is a functional bowel disorder (FBD). OBJECTIVES: To assess the therapeutic effects of paeoniflorin (PF) on IBS in rats. METHOD: Sixty male Sprague-Dawley rats were randomly divided into normal, model, positive drug, low-dose PF, medium-dose PF and high-dose PF groups (n = 10). After gavage for 2 consecutive weeks, the effect of PF on abdominal pain symptoms was assessed based on the abdominal withdrawal reflex (AWR) score, fecal water content and pathological changes in colon tissues. D-lactate, interleukin-1ß (IL-1ß), transforming growth factor-ß (TGF-ß) and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immunosorbent assay, and phosphorylated nuclear factor kappa B (p-NF-κB) p65 was detected by Western blotting. The abundance and diversity changes of intestinal flora were explored using 16S ribosomal RNA sequencing. RESULT: In PF groups, the mucosal morphology of colon tissues was intact, and the glands were arranged neatly and structured clearly, without obvious inflammatory cell infiltration. Compared with the model group, PF groups had significantly elevated pain threshold, and mRNA and protein levels of zonula occludens-1 (ZO-1) and occludin, decreased AWR score at 20 mmHg pressure, fecal water content, mRNA levels of IL-1ß, TGF-ß, and TNF-α, protein level of p-NF-κB p65 and level of serum D-lactate, and reduced levels of serum IL-1ß, TGF-ß, and TNF-α (p < 0.05, p < 0.01). PF groups had higher abundance of Lactobacillus, Akkermansia, Alistipes, and Bacteroides, but lower abundance of Desulfovibrio, Parasutterella, and Enterococcus than those of the model group. CONCLUSIONS: PF exerts therapeutic effects on IBS in rats probably by regulating the intestinal flora, and then up-regulating the expressions of ZO-1 and occludin in colon tissue while down-regulating the levels of IL-1ß, TGF-ß, TNF-α, D-lactate and p-NF-κB p65.