[Research progress in signaling pathways related to treatment of functional dyspepsia with traditional Chinese medicine].

Functional dyspepsia(FD) is a prevalent functional gastrointestinal disease characterized by recurrent and long-lasting symptoms that significantly impact the quality of life of patients. Currently, western medicine treatment has not made breakthrough progress and mainly relies on symptomatic therapies such as gastrointestinal motility agents, acid suppressants, antidepressants/anxiolytics, and psychotherapy. However, these treatments have limitations in terms of insufficient effectiveness and safety. Traditional Chinese medicine(TCM) possesses unique advantages in the treatment of FD. Through literature search in China and abroad, it has been found that the mechanisms of TCM in treating FD is associated with various signaling pathways, and research on these signaling pathways and molecular mechanisms has gradually become a focus. The main signaling pathways include the SCF/c-Kit signaling pathway, 5-HT signaling pathway, CRF signaling pathway, AMPK signaling pathway, TRPV1 signaling pathway, NF-κB signaling pathway, and RhoA/ROCK2/MYPT1 signaling pathway. This series of signaling pathways can promote gastrointestinal motility, alleviate anxiety, accelerate gastric emptying, reduce visceral hypersensitivity, and improve duodenal micro-inflammation in the treatment of FD. This article reviewed the research on TCM's regulation of relevant signaling pathways in the treatment of FD, offering references and support for further targeted TCM research in the treatment of FD.

[Effect of electroacupuncture at "Zusanli" (ST 36) on duodenal mast cells, NGF and NTRK1 in rats with functional dyspepsia].

OBJECTIVE: To observe the effect of electroacupuncture (EA) at "Zusanli" (ST 36) on duodenal mast cells, nerve growth factor (NGF) and neurotrophic tyrosine kinase receptor type 1 (NTRK1), and to explore the mechanism of electroacupuncture at Zusanli (ST 36) on functional dyspepsia (FD). METHODS: Sixty SPF-grade 10-day-old SD rats were randomly divided into a normal group, a model group, a ketotifen group and an EA group, 15 rats in each group. The FD model was prepared by iodoacetamide combined with rat tail clamping method in the model group, the ketotifen group and the EA group. The rats in the ketotifen group were injected intraperitoneally with ketotifen (1 mg•kg-1•d-1) for 7 days; the rats in the EA group were treated with EA at bilateral "Zusanli" (ST 36), with disperse-dense wave, frequency of 2 Hz/50 Hz and intensity of 0.5 mA, 20 min each time, once a day for 14 days. The gastric emptying rate and small intestinal propulsion rate in each group were observed; the morphology of duodenal mucosa was observed by HE staining; the toluidine blue staining was used to observe the number and degranulation of mast cells in duodenal mucosa; the protein and mRNA expressions of NGF, NTRK1 in duodenum were detected by Western blot and real-time PCR; the level of interleukin-1ß (IL-1ß) in duodenum was measured by ELISA. RESULTS: Compared with the normal group, the gastric emptying rate and small intestinal propulsion rate in the model group were decreased (P<0.01); compared with the model group, the gastric emptying rate and small intestinal propulsion rate in the ketotifen group and the EA group were increased (P<0.01); the small intestinal propulsion rate in the EA group was higher than that in the ketotifen group (P<0.01). In the model group, local defects in duodenal mucosa were observed with a small amount of inflammatory cell infiltration; no obvious abnormality was found in duodenal mucosa of the other groups. Compared with the normal group, the mast cells of duodenal mucosa in the model group were increased significantly with significant degranulation; compared with the model group, the mast cells of duodenal mucosa in the ketotifen group and the EA group were decreased significantly, and the degranulation was not obvious. Compared with the normal group, the protein and mRNA expressions of NGF, NTRK1 as well as the level of IL-1ß in duodenum in the model group were increased (P<0.01); compared with the model group, the protein and mRNA expressions of NGF, NTRK1 as well as the levels of IL-1ß in duodenum in the ketotifen group and the EA group were decreased (P<0.01, P<0.05); compared with the ketotifen group, the mRNA expression of NGF, as well as the protein and mRNA expressions of NTRK1 in duodenum in the EA group were decreased (P<0.05, P<0.01). CONCLUSION: EA at "Zusanli" (ST 36) could inhibit the activation of duodenal mast cells and regulate the expressions of NGF and its receptor to improve the low-grade inflammatory response of duodenum, resulting in treatment effect on FD.

[Influence of electroacupuncture of"Zusanli"(ST36)on mast cells/TRPV1 signaling pathway in visceral hypersensitivity rats with functional dyspepsia].

OBJECTIVE: To explore the interventional mechanism of electroacupuncture (EA) of "Zusanli"(ST36)based on the involvement of mast cells/ transient receptor potential vanilloid type1 (TRPV1) signaling pathway in relieving visceral hypersensitivity in functional dyspepsia (FD) rats. METHODS: Sixty SD rats (half male and half female, 10 days in age) were randomly divided into normal control, model, medication (ketotifen) and EA groups, with 15 rats in each group. The FD model was established by gavage of iodoacetamide combined with tail clamping (stress stimulation). Rats of the medication group received intraperitoneal injection of ketotifen (1 mg·kg-1·d-1) for 14 d, and those of the EA group received EA of ST36 for 20 min, once a day for 14 d. An air-balloon was inserted into the rat's stomach for recording changes of the intragastric pressure (mL/mm Hg) via a pressure transducer. The visceral hypersensitivity was assessed using abdominal withdrawal reflex (AWR) score and the number and degranulation of mast cells of gastric mucosa were observed using toluidine blue staining. The expression levels of TRPV1 and proteinase activated receptor 2 (PAR2) in the stomach were observed using immunofluorescence histochemistry and Western blot, separately, and the contents of SP and CGRP in the stomach detected using ELISA. RESULTS: When the intragastric pressure was at 50, 60 and 70 mm Hg, the gastric compliance was significantly decreased (P<0.01), and the levels of visceral sensitivity increased in the model group （P<0.01）。 TRPV1 immunofluorescence tensity, expression of PAR2 and TRPV1 proteins, and contents of SP and CGRP in the stomach were considerably up-regulated in the model group compared with the normal control group (P<0.01). In comparison with the model group, under intragastric pressure of 50，60 and 70 mm Hg, the gastric compliance was obviously increased, and the visceral hypersensitivity decreased in the EA group （P<0.01,P<0.05）. TRPV1 immunofluorescence intensity, expression levels of PAR2 and TRPV1 proteins, and the contents of SP and CGRP in the stomach were considerably down-regulated in both medication and EA groups compared with the model group (P<0.01, P<0.05). The therapeutic effect of EA was significantly superior to that of medication in up-regulating the gastric compliance （at 70 mm Hg）, and down-regulating the contents of SP and CGRP (P<0.05). No significant differences were found between the EA and medication groups in up-regulating gastric compliance at intragastric pressure of 50 and 60 mm Hg, and in down-regulating the visceral sensitivity, TRPV1 fluorescence intensity, and expression of PAR2 and TRPV1 proteins (P>0.05). Toluidine blue staining showed an apparent increase of mast cell number with obvious degranulation in the gastric mucosa of rats in the model group, which was milder in the EA and medication groups. CONCLUSION: EA of ST36 can suppress visceral hypersensitivity and increase the gastric compliance in FD rats, which may be related with its effects in inhibiting the activation of gastric mast cells, and down-regulating the expression of gastric PAR2 and TRPV1 proteins and SP and CGRP contents.

[Transcutaneous auricular vagus nerve stimulation promotes gastric motility by up-rgulating α7nAChR and suppressing NF-κB p65 expression in duodenum in rats with functional dyspepsia].

OBJECTIVE: To study the effect of transcutaneous auricular vagus nerve stimulation (taVNS) on gastric sensitivity and motility in rats with functional dyspepsia (FD), so as to explore its underlying mechanism in improving FD. METHODS: A total of 48 young SD rats were randomly divided into control (n=10), model (n=9), taVNS (n=9), subdiaphragmatic vagus nerve stimulation (SDVNS, n=9) and sham SDVNS (n=7) groups. The FD model was established by gavage of 0.1% iodoa-cetamide+2% glucose, once daily for 6 days. Rats in the taVNS group received taVNS (0.5 mA) of optopoint "Heart" and "Stomach" for 30 min, once daily for 14 days, while rats in the SDVNS group received subdiaphragmatic vagus nerve stimulation through the implanted electrode, and those of the sham SDVNS group received only application of the same electrodes without electrical stimulation. Electromyogram (EMG) of the cervical trapezius muscle (reflecting gastric sensitivity) was recorded before and after intragastric expansion via an air ballon and the gastric emptying rate was calculated for assessing the gastric motility. The contents of acetylcholine (ACh), nicotinic acetylcholine receptor α7 subunit (α7nAChR), interleukin-6 (IL-6), interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) in the duodenum tissue were detected by enzyme-linked immunosorbent assay (ELISA). The expression of nuclear factor kappa B (NF-κB) p65 in the duodenum tissue was determined by Western blot. RESULTS: In comparison with the control group, the EMG change rate at intragastric pressure levels of 40, 60 and 80 mm Hg, expression of NF-κB p65 protein, and contents of IL-6, IL-1ß and TNF-α were significantly increased (P<0.05,P<0.01, P<0.001), while the gastric emptying rate, ACh and α7nAChR contents considerably decreased (P<0.05, P<0.001) in the model group. After interventions, the EMG change rate, contents of IL-6, IL-1ß and TNF-α, and expression of NF-κB p65 were notably decreased (P<0.05, P<0.01, P<0.001), and the gastric emptying rate, ACh and α7nAChR contents obviously increased (P<0.05, P<0.001) in both taVNS and SDVNS groups relevant to the model group. In comparison with the sham SDVNS group, the EMG change rate, contents of IL-6, IL-1ß and TNF-α, and expression of NF-κB p65 were notably decreased (P<0.01, P<0.05,P<0.001), and the gastric emptying rate, ACh and α7nAChR contents obviously increased (P<0.01, P<0.001) in the both SDVNS and taVNS groups. CONCLUSION: taVNS can reduce gastric sensitivity and promote gastric emptying in FD model rats, which may be closely related to its functions in up-regulating ACh and α7nAChR contents and inhibiting the activation of NF-κB p65 signaling in the duodenum.

Moxibustion Regulates Gastrointestinal Motility via HCN1 in Functional Dyspepsia Rats.

BACKGROUND Moxibustion therapy has been found to ameliorate clinical symptoms of functional dyspepsia (FD). We aimed to examine the regulatory effect of moxibustion on the gastrointestinal (GI) motility in FD and explore the underlying mechanism based on the hyperpolarization-activated cyclic nucleotide-gated cation channel 1 (HCN1). MATERIAL AND METHODS Moxibustion therapy was used in FD rats induced by using classic tail-pinch and irregular feeding. Weight gain and food intake were recorded weekly, followed by detecting gastric residual rate (GRR) and small intestine propulsion rate (IPR). Next, western blotting was performed to determine the expression levels of HCN1 in the gastric antrum. qRT-PCR was used to detect HCN1 in the small intestine and hypothalamic satiety center. Double immunolabeling was used for HCN1 and ICCs in gastric antrum and small intestine. RESULTS The obtained results suggested that moxibustion treatment could increase weight gain and food intake in FD rats. The GRR and IPR were compared among the groups, which showed that moxibustion treatment could decrease GRR and increase IPR. Moxibustion increased the expression of HCN1 in the gastric antrum, small intestine, and hypothalamic satiety center. Histologically, the co-expressions of HCN1 and ICCs tended to increase in gastric antrum and small intestine. Meanwhile, HCN channel inhibitor ZD7288 prevented the above-mentioned therapeutic effects of moxibustion. CONCLUSIONS The results of the present study suggest that moxibustion can effectively improve the GI motility of FD rats, which may be related to the upregulation of HCN1 expression in gastric antrum, small intestine, and satiety center.

Banha-sasim-tang improves gastrointestinal function in loperamide-induced functional dyspepsia mouse model.

ETHNOPHARMACOLOGICAL RELEVANCE: Banha-sasim-tang (BST; Hange-shashin-to in Kampo medicine; Banxia xiexin tang in traditional Chinese medicine) is a traditional Chinese harbal medicine that has been commonly used for gastrointestinal disorders. AIM OF THE STUDY: To investigate the pharmacological effects of BST, a standardized herbal drug, on main symptoms of functional dyspepsia including delayed gastric emptying, and underlying mechanisms of action in mouse model. METHODS AND MATERIALS: Balb/C mice were pretreated with BST (25, 50, 100 mg/kg, po) or mosapride (3 mg/kg, po) for 3 days, and then treated with loperamide (10 mg/kg, ip) after 19 h fasting. A solution of 0.05% phenol red (500 µL) or 5% charcoal diet (200 µL) was orally administered, followed by scarifying and assessment of gastric emptying or gastro-intestinal motility. C-kit (immunofluorescence), nNOS (western blot) and gastric contraction-related gene expression were examined in stomach tissue. RESULTS: The loperamide injection substantially delayed gastric emptying, while the BST pretreatment significantly attenuated this peristaltic dysfunction, as evidenced by the quantity of stomach-retained phenol red (p < 0.05 or 0.01) and stomach weight (p < 0.05 or 0.01). The BST pretreatment significantly tempered the loperamide-induced inactivation of c-kit and nNOS (p < 0.05 or 0.01) as well as the contraction-related gene expression, such as the 5HT4 receptor (5HT4R), anoctamin-1 (ANO1), ryanodine receptor 3 (RYR3) and smooth muscle myosin light chain kinase (smMLCK). The BST pretreatment also significantly attenuated the alterations in gastro-intestinal motility (p < 0.01). CONCLUSION: Our results are the first evidence of the prokinetic agent effects of Banha-sasim-tang in a loperamide-induced FD animal model. The underlying mechanisms of action may involve the modulation of peristalsis via activation of the interstitial cells of Cajal and the smooth muscle cells in the stomach.

Sini-san improves duodenal tight junction integrity in a rat model of functional dyspepsia.

BACKGROUND: Recent reports have demonstrated that impaired barrier function and local microinflammation in the duodenal mucosa contribute to the pathogeneses of functional dyspepsia (FD). Thus, restoring normal barrier integrity becomes a potential therapeutic strategy in the treatment of FD. Sini-San (SNS) is a traditional Chinese prescription that exhibits therapeutic effects in FD, but the underlying mechanisms remain not well understood. METHODS: FD rats were established by tail clamping method and the therapeutic effect of SNS was evaluated by measuring the visceral sensitivity and gastric compliance. Transepithelial electrical resistance (TEER) that reveals epithelial barrier integrity was measured by Ussing chamber. The expression of tight junction (TJ) proteins, occludin and claudin-1, in the duodenum was determined by Western blot and immunofluorescence. The amount of tumor necrosis factor alpha (TNF-α) and interferon gamma (INF-γ) in duodenal mucosa was detected by enzyme-linked immune sorbent assay (ELISA). The mRNA level of transient receptor potential vanilloid type 1 (TRPV1) was measured by quantitative real time-polymerase chain reaction (qPCR). RESULTS: SNS could improve gastric compliance and attenuate visceral hypersensitivity (VH) in FD rats. TEER was decreased in FD rats, but treatment with SNS restored normal level of TEER and the expression of occludin and claudin-1 in FD rats. In addition, SNS administration ameliorated FD-associated increase in the production of TNF-α, IFN-γ and the expression of TRPV1. CONCLUSIONS: The therapeutic effect of SNS on FD is at least partially through improvement of TJ integrity and attenuation of FD-associated low-grade inflammation in the duodenum. Our findings highlight the molecular basis of SNS-based treatment of FD in human patients.

Dietary PUFA Increase Apoptosis in Stomach of Patients with Dyspeptic Symptoms and Infected with H. pylori.

Drug-resistant strains of Helicobacter pylori and poor treatment response are the main reasons for the failure in eradicating it in patients. Polyunsaturated fatty acids (PUFA) have an inhibitory effect on bacterial growth. The aim of this study was to investigate the effect of PUFA in combination with standard triple therapy on apoptosis in H. pylori infected subjects with dyspeptic symptoms. This study was a double-blind clinical trial in which 34 H. pylori infected subjects with dyspeptic symptoms were randomly divided into two groups of 17 patients. The control group received standard triple therapy (amoxicillin, clarithromycin and omeprazole) and the experimental group received the standard therapy and PUFA for two weeks. Gene expression levels of caspase-3, BCL-2 and Bad proteins were studied with real-time PCR, while protein levels were quantified in frozen sections and using immunohistochemistry. Compared with the control group, a significant increase (p < 0.01) was observed in the expression of caspase-3 and Bad genes and a significant reduction (p < 0.05) in the expression of Bcl-2 gene. The protein level of active caspase-3 and Bad protein was significantly increased and the level of Bcl-2 protein was significantly decreased (p < 0.05). The results of this study show that oral administration of PUFA in combination with the standard triple therapy increased apoptosis in H. pylori-infected patients with dyspeptic symptoms. This increase in apoptosis may partly reduce drug resistance in these patients. Our results suggest inclusion of a dietary PUFA containing fatty acid supplement may improve treatment of patients that are refractory to the standard triple therapy.

[Involvement of Neurotensin-mediated Brain-gut Axis in Electroacupuncture Intervention Induced Improvement of Functional Dyspepsia in Rats].

OBJECTIVE: To observe The effect of electroacupuncture (EA) stimulation of "Zusanli" (ST 36) and "Taichong" (LR 3) on intestinal motor and neurotensin (NT) levels in the plasma, hypothalamus, and gastro-antrum tissues in functional dyspepsia (FD) rats so as to reveal its mechanisms underlying improvement of FD. METHODS: Forty-eight SD rats were randomly divided into control, model and EA groups, with 16 rats in each group. The FD model was established by clamping the rats' tails and alternate day's feeding according to the related references. EA (2 Hz/100 Hz, 2 mA) was applied to unilateral ST 36 and LR 3 for 30 min, once daily for 14 days. Rats of the control group were only restricted. The gastric emptying rate and propulsive rate of the small intestine were detected. The content of NT in the plasma was assayed using ELISA, and the immunoactivity levels of NT in the hypothalamus, gastric antrum mucous membrane and ileum tissues were detected using immunohistochemistry. RESULTS: Compared with the control group, the gastric emptying rate and propulsive rate of the small intestine were considerably lowered in the model group (P < 0.01), and the content and immunoactivity levels of NT in the plasma, hypothalamus, mucous membrane of the gastric antrum and ileum tissues were significantly increased (P < 0.05). After EA intervention, the decreased gastric emptying rate and intestinal propulsive rate, as well as the increased NT content and immunoactivity levels of plasma, hypothalamus, gastric antrum and ileum were reversed (P < 0.05). CONCLUSION: EA intervention can obviously promote gastrointestinal motor in FD rats, which may be related to its function in down-regulating NT levels in the plasma, hypothalamus, gastric antrum and ileum. It suggests an involvement of NT in the brain-gut axis in EA-induced improvement of FD.

[Research progress of mechanism of functional dyspepsia treated with acupuncture].

Literature about functional dyspepsia treated with acupuncture in recent 5 years is retrieved in China National Knowledge Infrastructure (CNKI), Wanfang database and PubMed. The research achievements are arranged and summed up to explore the mechanism of acupuncture for functional dyspepsia. It is found that acupuncture can regulate the secretion of braingut petide, and cause the coordination response of limbic system-brain. Also, it adjusts serum molecule metabolin and the gene expression of the transduction pathway of adjustment signal for rats. It is believed that functional dyspepsia treated with acupuncture is through multiple ways, and adjusting the function of braingut axis is one of the important mechanisms.

[Effect of method of soothing liver and regulating qi on expression of gastrin and somatostatin in hypothalamus, castric antrum of functional dyspepsia rats].

OBJECTIVE: To explore the effects of the method of soothing the liver and regulating qi on expression of gastrin and somatostatin in hypothalamus and gastric antrum of functional dyspepsia model rats. METHOD: The 32 rats were randomly divided into normal group, model group, Chaihu Shugansan group and domperidone group (n = 8). The functional dyspepsia model was established by constantly squeezing their tails and mean while saline, Chaihu Shugansan decoction and domperidone suspension were administered respectively to 4 groups by gavage. The expression of gastrin and somatostatin in hypothalamus and gastric antrum of rats by immunohistochemical were detected 3 weeks later. RESULT: The expression of GAS in the hypothalamus and gastric antrum of model group were less than those of normal group (P < 0.05, P < 0.01), while the expression of SS in the hypothalamus and gastric antrum in Model group were significantly increased than those of normal group (P < 0.01). The expression of GAS and SS in gastric antrum of Chaihu Shugansan group and domperidone group were increased and decreased respectively, and the differences were significant (P < 0.05, P < 0.01). There were no obvious difference about expression of GAS, SS in the hypothalamus between domperidone group and model group. GAS expression in hypothalamus of Chaihu Shugansan group were increased than those of normal group but there was no obvious difference in SS expression in hypothalamus between Chaihu Shugansan group and model group. CONCLUSION: The method of soothing the liver and regulating qi can increase GAS expression in central and peripheral and decrease SS expression in peripheral gastric antrum, which may be one of its therapeutic mechanisms on functional dyspepsia.

Adaptive upregulation of gastric and hypothalamic ghrelin receptors and increased plasma ghrelin in a model of cancer chemotherapy-induced dyspepsia.

Chemotherapy treatment can lead to delayed gastric emptying, early satiety, anorexia, nausea and vomiting, described collectively as the cancer-associated dyspepsia syndrome (CADS). Administration of ghrelin (GHRL), an endogenous orexigenic peptide known to stimulate gastric motility, has been shown to reduce the symptoms of CADS induced in relevant animal models with the potent chemotherapeutic agent, cisplatin. We examined the effects in the rat of cisplatin (6 mg/kg i.p.) treatment on the expression of GHRL and ghrelin receptor (GHSR) mRNAs in the hypothalamus and the stomach at a time-point (2 days) when the effects of cisplatin are pronounced. In addition, plasma levels of GHRL (acylated and total including des-acyl GHRL) were measured and the effect on these levels of treatment with the synthetic glucocorticoid dexamethasone (2 mg/kg s.c. bd.) was investigated. Cisplatin increased GHSR mRNA expression in the stomach (67%) and hypothalamus (52%) but not GHRL mRNA expression and increased the percentage of acylated GHRL (7.03+/-1.35% vs. 11.38+/-2.40%) in the plasma. Dexamethasone reduced the plasma level of acylated GHRL and the percentage of acylated GHRL to values below those in animals treated with saline alone (7.03+/-1.35% vs. 2.60+/-0.49%). Our findings support the hypothesis that an adaptive upregulation of the ghrelin receptor may occur during cancer chemotherapy-associated dyspepsia. This may have a role in defensive responses to toxic challenges to the gut. In addition, our results provide preliminary evidence for glucocorticoid modulation of plasma ghrelin levels.