Protective effect of Rhei Rhizoma on reflux esophagitis in rats via Nrf2-mediated inhibition of NF-κB signaling pathway

The role of the esophageal and intestinal microbiome in gastroesophageal reflux disease: past, present, and future

Gastroesophageal reflux disease (GERD) is one of the common diseases of the digestive system, and its incidence is increasing year by year, in addition to its typical symptoms of acid reflux and heartburn affecting the quality of patients' survival. The pathogenesis of GERD has not yet been clarified. With the development of detection technology, microbiome have been studied in depth. Normal microbiome are symbiotic with the host and can assist the host to fulfill the roles of digestion and absorption, and promote the development of the host. Dysbiosis of the microbiome forms a new internal environment, under which it may affect the development of GERD from the perspectives of molecular mechanisms: microbial activation of Toll-like receptors, microbial stimulation of cyclooxygenase-2 expression, microbial stimulation of inducible nitrous oxide synthase, and activation of the NLRP3 inflammatory vesicle; immune mechanisms; and impact on the dynamics of the lower gastrointestinal tract. This review will explore the esophageal microbiome and intestinal microbiome characteristics of GERD and the mechanisms by which dysbiotic microbiome induces GERD.

Ameliorative Effects of HT074-Inula and Paeonia Extract Mixture on Acute Reflux Esophagitis in Rats via Antioxidative Activity

HT074, a multiherbal mixture containing extracts from Inula britannica flowers and Paeonia lactiflora roots, is used in Korean medicine for gastric disorders. This study investigated the protective mechanisms of HT074 against acute reflux esophagitis (RE) in rats. Nitric oxide (NO) production and mRNA expression of antioxidant-related genes (Nrf2, HO-1, SOD, CAT, and GPx2) were evaluated in LPS-induced RAW 264.7 cells. Gastroesophageal reflux (GER) was induced in rats, followed by HT074 (100, 300 mg/kg) or ranitidine (50 mg/kg) administration. Esophageal damage and histological changes were assessed. Gastric pH and protein expression levels of Nrf2, HO-1, SOD, CAT, and GPx-1/2 were measured. HT074 pretreatment reduced NO production and increased the expression of HO-1, CAT, and GPx2 in LPS-induced RAW 264.7 cells. In GER-induced rats, HT074 significantly decreased esophageal lesions and increased the expression of HO-1, SOD, GPx-1/2, and Nrf2. HT074 did not affect gastric pH. These findings suggest that HT074 protects against GER-induced esophagitis by inhibiting NO production and enhancing antioxidant activity. Therefore, HT074 could be a promising therapeutic agent for GER disease.

Columbianadin ameliorates experimental acute reflux esophagitis in rats via suppression of NF-κB pathway

PURPOSE

Reflux esophagitis is a condition characterized by inflammation and irritation of the esophagus, resulting from the backflow of stomach acid and other gastric contents into the esophagus. Columbianadin is a coumarin derivative that exhibits anti-inflammatory and antioxidant effects. In this study, we tried to scrutinize the protective effect of Columbianadin against acute reflux esophagitis in rats.

METHODS

RAW 264.7 cells were utilized to assess cell viability and measure the production of inflammatory parameters. The rats received anesthesia, and reflux esophagitis was induced via ligation of pylorus and fore stomach and corpus junction. Rats received the oral administration of Columbianadin (25, 50 and 100 mg/kg) and omeprazole (20 mg/kg). The gastric secretion volume, acidity, and pH were measured. Additionally, the levels of oxidative stress parameters, cytokines, and inflammatory markers were determined. At the end of the study, mRNA expression was assessed.

RESULTS

Columbianadin remarkably suppressed the cell viability and production of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and prostaglandin (PGE2). Columbianadin treatment remarkably suppressed the secretion of gastric volume, total acidity and enhanced the pH level in the stomach. Columbianadin remarkably altered the level of hydrogen peroxidase, free iron, calcium, and plasma scavenging activity, sulfhydryl group; oxidative stress parameters like malonaldehyde, glutathione, superoxide dismutase, catalase, glutathione peroxidase; inflammatory cytokines viz., TNF-α, IL-6, IL-1β, IL-10, IL-17, and monocyte chemoattractant protein-1; inflammatory parameters including PGE2, iNOS, COX-2, and nuclear kappa B factor (NF-κB). Columbianadin remarkably (P < 0.001) suppressed the mRNA expression TNF-α, IL-6, IL-1β and plasminogen activator inhibitor-1.

CONCLUSIONS

Columbianadin demonstrated a protective effect against acute reflux esophagitis via NF-κB pathway.

Herbal Combination 'HAGE-101912' Ameliorates Gastroesophageal Reflux Disease in Rats

Background

Gastroesophageal reflux disease (GERD) is a chronic, relapsing disorder. In this era of modern and fast-track lifestyle and food habits, the incidence of GERD is rapidly increasing. Currently, proton pump inhibitors (PPIs) are the primary choice of treatment. However, the associated side effects and a high relapse rate give rise to the need to explore alternative therapies.

Objective

The study aimed to evaluate HAGE-101912, an herbal combination, in different experimental models of GERD.

Methods

Antacid activity was assessed based on H+/K+ATPase inhibitory activity of parietal cells using artificial gastric juice. Tonic contraction of the lower esophageal sphincter (LES) was evaluated using an AD Instrument. A GERD model of the pylorus and fundus ligation (preventive and curative models) in rats was selected to assess the efficacy of HAGE-101912 at a dose of 250 mg/kg body weight, and various parameters such as the gastric pH, gastric volume, total acidity, gross esophageal ulcer index, and histopathological changes were evaluated. The prokinetic activity was assessed using the phenol red method.

Results

HAGE-101912 increased the acid-neutralizing capacity (P < 0.001), decreased H+/K+ATPase activity (P < 0.01), and increased the contraction of the LES. In the preventive model, HAGE-101912 significantly reduced the gastric acid volume (P < 0.01), total acidity (P < 0.001), and gross esophageal ulcer index (P < 0.01); increased the gastric acid pH (P < 0.01); and protected the esophageal epithelium. In addition, HAGE-101912 increased gastric emptying and gastrointestinal transit through its prokinetic activity (P < 0.05).

Conclusion

HAGE-101912 has a beneficial effect in GERD as it effectively inhibits the H+/K+ATPase, increases the gastric pH, restores the LES function, protects the esophageal epithelium, and increases gastric emptying and transit.

Quality assessment of Rheum species cultivated in Japan by focusing on M2 polarization of microglia

In traditional Japanese medicine, Rhei Rhizoma is used as a purgative, blood stasis-resolving and antipsychotic drug. The latter two properties are possibly related to anti-inflammatory effects. Microglia regulate inflammation in the central nervous system. M1 microglia induce inflammation, while M2 microglia inhibit inflammation and show neurotrophic effects. This study investigated the effects from water extracts of roots of cultivated Rheum species in Nagano Prefecture, Japan (strain C, a related strain to a Japanese cultivar, 'Shinshu-Daio'; and strain 29, a Chinese strain) and 3 kinds of Rhei Rhizoma available in the Japanese market, and also examined their constituents on the polarization of cultured microglia. All extracts significantly decreased M1 microglia, and strains C and 29 significantly increased M2 microglia. Furthermore, the extracts of both strains significantly increased the M2/M1 ratio. Among the constituents of Rhei Rhizoma, ( +)-catechin (2), resveratrol 4'-O-β-D-(6″-O-galloyl) glucopyranoside (5), isolindleyin (8), and physcion (15) significantly increased the M2/M1 ratio. The contents of the constituents in water extract of each strain were quantified using HPLC. The extracts of strains C and 29 contained relatively large amounts of 2 and 5; and 2, 8, and 15, respectively. This study showed the water extracts of roots of cultivated Rheum strains in Japan had the effects of M2 polarization of microglia, suggesting that these strains become the candidate to develop anti-inflammatory Rhei Rhizoma. Moreover, the suitable chemical composition to possess anti-inflammatory activity in the brain was clarified for the future development of new type of Rhei Rhizoma.

Liangxue Tongyu Prescription Alleviates Brain Damage in Acute Intracerebral Hemorrhage Rats by Regulating Intestinal Mucosal Barrier Function

Background

Liangxue Tongyu prescription (LTP) is a commonly used formula for acute intracerebral hemorrhage (AICH) in clinical practice that has significant ameliorative effects on neurological deficits and gastrointestinal dysfunction, yet the mechanism remains elusive. The aim of this study was to investigate the pathway by which LTP alleviates brain damage in AICH rats.

Methods

The AICH rat models were established by autologous caudal arterial blood injection. The neurological function scores were evaluated before and after treatment. The water content and the volume of Evans blue staining in the brain were measured to reflect the degree of brain damage. RT-PCR was used to detect the inflammatory factors of the brain. Western blotting was used to detect the expression of the tight junction proteins zonula occludens 1 (ZO-1), occludin (OCLN), and claudin (CLDN) in the brain and colon, followed by mucin 2 (MUC2), secretory immunoglobulin A (SIgA), and G protein-coupled receptor 43 (GPR43) in the colon. Flow cytometry was used to detect the ratios of helper T cells 17 (Th17) and regulatory T cells (Treg) in peripheral blood, and the vagus nerve (VN) discharge signals were collected.

Results

LTP reduced the brain damage of the AICH rats. Compared with the model group, LTP significantly improved the permeability of the colonic mucosa, promoted the secretion of MUC2, SigA, and GPR43 in the colon, and regulated the immune balance of peripheral T cells. The AICH rats had significantly faster VN discharge rates and lower amplitudes than normal rats, and these abnormalities were corrected in the LTP and probiotics groups.

Conclusion

LTP can effectively reduce the degree of brain damage in AICH rats, and the mechanism may be that it can play a neuroprotective role by regulating the function of the intestinal mucosal barrier.

Effects of Jowiseungki-tang on high fat diet-induced obesity in mice and functional analysis on network pharmacology and metabolomics analysis

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Chinese and Korean medicine, Jowiseungki-tang (JST) is a prescription for diabetes mellitus (DM) treatment. However, little scientific evidence is known of its effect in diabetic condition.

AIMS

We assessed the effects of JST on high-fat diet (HFD)-induced obesity with inflammatory condition in mice and to analyze the therapeutic function of JST on network pharmacology as well as targeted metabolomics.

MATERIALS AND METHODS

JST administration at 100 mg/kg and 500 mg/kg for a period of 4 weeks in HFD-induced obese mice, body weight gain, energy utility, calorie intake, and levels of glucose, insulin, total cholesterol, triglyceride, LDL-cholesterol as well as interleukin-6 were measured. Measurements of HDL-cholesterol (HDL-C) were performed and compared to those of the control group. Moreover, the therapeutic function of JST on obesity was analyzed furtherly based on network pharmacology and targeted metabolomics methods.

RESULTS

Administration of JST at 100 mg/kg and 500 mg/kg for a period of 4 weeks in HFD-induced obesity mice significantly decreased the body weight gain, energy utility, calorie intake, and levels of insulin, total cholesterol, LDL-cholesterol, triglyceride, and interleukin-6. However, HDL-cholesterol (HDL-C) levels showed marked elevation relative to control groups. JST administration strongly inhibited expressions of inducible nitric oxide synthase, inflammatory proteins, and cyclooxygenase-2 in the pancreas, stomach, and liver tissues, and reduced hepatic steatosis and pancreatic hyperplasia. In network pharmacological analysis, the putative functional targets of JST are underlie on modulation of cofactor-, coenzyme-, and fatty acid-bonding, insulin resistance, and inflammatory response, fine-tuned the phosphatase binding and signal pathway activation, such as mitogen activated protein kinases, phosphatidylinositol 3-kinases/protein kinase B, protein kinase C, and receptor of glycation end products as well-advanced glycation end products. According to the metabolomics analysis, the contents and energy metabolites, and medium and long chain fatty acids was significantly changed in mice pancreases.

CONCLUSIONS

JST is a valuable prescription for treatment of patients with DM in traditional clinics through inhibition of obesity, inflammatory condition and metabolism.

Protective Effects of Inflammation of Curcumae Longae Rhizoma 30% EtOH Extract on Acute Reflux Esophagitis Rats

Gastroesophageal reflux disease (GERD) is induced by the reflux of stomach contents or gastric acid, pepsin into the esophagus for prolonged periods of time due to defection of the lower esophageal sphincter. Reflux esophagitis is a disease found in less than 50% of GERD patients. This study is aimed at evaluating the protective effect of Curcumae longae Rhizoma 30% EtOH extract (CLR) in acute reflux esophagitis (ARE) rats. CLR measured antioxidant activity through in vitro experiments. Based on the results, we performed experiments in vivo. Before 90 min ARE induction, CLR was administered orally by concentration. ARE was derived by linking the metastatic junction between pylorus and forestomach and corpus in Sprague-Dawley rats. And rats were sacrificed 5 h after surgery. We analyzed the expression of antioxidant and inflammatory-related markers by western blot and observed the production of alanine aminotransferase (ALT), aspartate aminotransferase (AST), reactive oxygen species (ROS), peroxynitrite (ONOO⁻), and thiobarbituric acid reactive substance (TBARS). The administration of CLR reduced esophagus tissue damage in rats with acute reflux esophagitis and decreased the elevated ALT, AST, ROS, ONOO⁻, and TBARS. In addition, CLR effectively increased antioxidant-related factors and reduced inflammatory protein. Overall, these results suggest that CLR would be used as a therapeutic material in protection and treatment for ARE. Overall, CLR treatment informed that markedly ameliorated inactivation of NF-κB led to the inhibition of the expressions of proinflammatory proteins. These results suggest that CLR would be used as a therapeutic material in protection and treatment for ARE.

Inhibitory effects of Camellia japonica on cell inflammation and acute rat reflux esophagitis

Background

Excessive and continuous inflammation may be the main cause of various immune system diseases. Reflux esophagitis (RE) is a common gastroesophageal reflux disease (GERD). Camellia japonica has high medicinal value and has long been used as a traditional herbal hemostatic medicine in China and Korea. The purpose of this study is to explore the antioxidant and anti-inflammatory activities of CJE and its protective effect on RE.

Materials and methods

Buds from C. japonica plants were collected in the mountain area of Jeju, South Korea. Dried C. japonica buds were extracted with 75% ethanol. DPPH and ABTS radical scavenging assay were evaluated according to previous method. The ROS production and anti-inflammatory effects of C. japonica buds ethanol extract (CJE) were evaluated on LPS-induced RAW 264.7 cell inflammation. The protective effects of CJE on RE were conducted in a RE rat model.

Results

CJE eliminated over 50% of DPPH and ABTS radical at concentration of 100 and 200 µg/mL, respectively. CJE alleviated changes in cell morphology, reduced production of ROS, NO and IL-1β. Also, down-regulated expression levels of iNOS, TNF-α, phosphorylated NF-κB, IκBα, and JNK/p38/MAPK. CJE reduced esophageal tissue damage ratio (40.3%) and attenuation of histological changes. In addition, CJE down-regulated the expression levels of TNF-α, IL-1β, COX-2 and phosphorylation levels of NF-κB and IκBα in esophageal tissue.

Conclusions

CJE possesses good anti-oxidation and anti-inflammatory activity, and can improve RE in rats caused by gastric acid reflux. Therefore, CJE is a natural material with good anti-oxidant and anti-inflammatory activity and has the possibility of being a candidate phytomedicine source for the treatment of RE.

Heme Oxygenase-1 in Gastrointestinal Tract Health and Disease

Heme oxygenase 1 (HO-1) is the rate-limiting enzyme of heme oxidative degradation, generating carbon monoxide (CO), free iron, and biliverdin. HO-1, a stress inducible enzyme, is considered as an anti-oxidative and cytoprotective agent. As many studies suggest, HO-1 is highly expressed in the gastrointestinal tract where it is involved in the response to inflammatory processes, which may lead to several diseases such as pancreatitis, diabetes, fatty liver disease, inflammatory bowel disease, and cancer. In this review, we highlight the pivotal role of HO-1 and its downstream effectors in the development of disorders and their beneficial effects on the maintenance of the gastrointestinal tract health. We also examine clinical trials involving the therapeutic targets derived from HO-1 system for the most common diseases of the digestive system.

Destruction of the Dorsal Motor Nucleus of the Vagus Aggravates Inflammation and Injury from Acid-Induced Acute Esophagitis in a Rat Model

Background/Aims

The aim of this study is to examine the protective effect of the cholinergic anti-inflammatory pathway (CAP) in experimental esophagitis in rats.

Methods

A total of 40 male Sprague-Dawley (SD) rats were randomly divided into five groups as follows: control group, sham + saline group, sham + acid group, operation + saline group, and operation + acid group. Two weeks after the dorsal motor nucleus of the vagus (DMV) destruction, hydrochloric acid with pepsin was perfused into the lower part of the esophagus for 90 min. The rats were sacrificed 60 min after perfusion. The esophagus was prepared for hematoxylin and eosin (HE) staining, and the degree of inflammation and NF-κB activation in the esophagus was measured. Inflammatory cytokines (TNF-α, IL-6, IL-1β, and PGE2) in the esophagus were measured by ELISA. The brain was removed and processed for c-fos immunohistochemistry staining. The c-fos-positive neurons were counted and analyzed.

Results

The TNF-α, IL-1β, IL-6, and PGE2 concentrations in the esophageal tissue increased after acid perfusion. The microscopic esophagitis scores and the activation of NF-κB p65 in the esophagus were significantly higher in the operation + acid group than in the operation + saline group. c-fos-positive neurons significantly increased in rats receiving acid perfusion in the amygdala (AM), the paraventricular nucleus of the hypothalamus (PVN), the parabrachial nucleus (PBN), the nucleus of the solitary tract (NTS)/DMV, the nucleus ambiguous (NA), the reticular nucleus of the medulla (RNM), and the area postrema (AP). After DMV destruction, c-fos expression was reduced in the AM, PVN, PBN, NTS/DMV, NA, RNM, and AP, especially in the AM, PVN, NTS/DMV, RNM, and AP.

Conclusions

The DMV is an important nucleus of the CAP. The DMV lesion can aggravate esophageal inflammation and injury from acid-induced acute esophagitis in a rat model. The CAP has a protective effect on the acute esophagitis rat model and could be a new therapy for reflux esophagitis (RE).

Critical Evaluation of Animal Models of Gastrointestinal Disorders

Preclinical research remains an important tool for discovery and validation of novel therapeutics for gastrointestinal disorders. While in vitro assays can be used to verify receptor-ligand interactions and test for structural activity of new compounds, only whole-animal studies can demonstrate drug efficacy within the gastrointestinal system. Most major gastrointestinal disorders have been modeled in animals; however the translational relevance of each model is not equal. The purpose of this chapter is to provide a critical evaluation of common animal models that are being used to develop pharmaceuticals for gastrointestinal disorders. For brevity, the models are presented for upper gastrointestinal disorders involving the esophagus, stomach, and small intestine and lower gastrointestinal disorders that focus on the colon. Particular emphasis is used to explain the face and construct validity of each model, and the limitations of each model, including data interpretation, are highlighted. This chapter does not evaluate models that rely on surgical or other non-pharmacological interventions for treatment.

Antioxidant and Anti-Inflammatory Effects of Herbal Formula SC-E3 in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages

SC-E3 is a novel herbal formula composed of five oriental medicinal herbs that are used to treat a wide range of inflammatory diseases in Korean traditional medicine. In this study, we sought to determine the effects of SC-E3 on free radical generation and inflammatory response in lipopolysaccharide- (LPS-) treated RAW 264.7 macrophages and the molecular mechanism involved. The ethanol extract of SC-E3 showed good free radical scavenging activity and inhibited LPS-induced reactive oxygen species generation. SC-E3 significantly inhibited the production of the LPS-induced inflammatory mediators, nitric oxide and prostaglandin E₂, by suppressing the expressions of inducible nitric oxide synthase and cyclooxygenase-2, respectively. SC-E3 also prevented the secretion of the proinflammatory cytokines, IL-1β, TNF-α, and IL-6, and inhibited LPS-induced NF-κB activation and the mitogen-activated protein kinase (MAPK) pathway. Furthermore, SC-E3 induced the expression of heme oxygenase-1 (HO-1) by promoting the nuclear translocation and transactivation of Nrf2. Taken together, these results suggest that SC-E3 has potent antioxidant and anti-inflammatory effects and that these effects are due to the inhibitions of NF-κB and MAPK and the induction of Nrf2-mediated HO-1 expression in macrophages. These findings provide scientific evidence supporting the potential use of SC-E3 for the treatment and prevention of various inflammatory diseases.

Effect of Pingchuan Guben decoction on patients with chronic obstructive pulmonary disease: Results from a randomized comparative effectiveness research trial

Chronic obstructive pulmonary disease (COPD) is known to be a systemic low-grade ongoing inflammation exerting major health and economic burden worldwide. Complementary and alternative medicines, such as Traditional Chinese Medicine, are widely used for the treatment of patients with COPD. The present study was designed to investigate the efficacy of Pingchuan Guben decoction on patients with COPD through a double-blinded, open-labeled, randomized controlled trial. A total of 86 patients were randomly assigned to two groups, with 43 patients in the intervention group and 43 cases in the control group. The patients in the control group were treated with conventional western medicine, and the intervention group received a combination of conventional western medicine and Pingchuan Guben decoction. After 12 weeks of treatment, the mean 6-minute walking distance, forced expiratory volume in 1 sec (FEV1), forced vital capacity (FVC) and FEV1/FVC in the intervention group were significantly higher than those of the control group (P<0.05). The levels of inflammation factors and protease molecules were significantly ameliorated in the intervention group compared with the control group (P<0.05). The levels of Kelch-like ECH-associated protein 1 (Keap1), nuclear factor-E2-related factor-2 (Nrf2), superoxide anions, malondialdehyde, glutathione S-transferase and glutathione peroxidase were significantly more improved in the intervention group compared with those in the control group over the 12-week study period (P<0.05). Therefore, combinations of western medicine with Pingchuan Guben decoction may exert therapeutic effects on patients with COPD via modulations of inflammation factors and protease molecules, as well as the activation of the Keap1/Nrf2 signaling pathway.

Modulatory effect of silymarin on nuclear factor-erythroid-2-related factor 2 regulated redox status, nuclear factor-κB mediated inflammation and apoptosis in experimental gastric ulcer

Non-steroidal anti-inflammatory drugs (NSAIDs) consumption has been commonly associated with gastric mucosal lesions including gastric ulcer. Silymarin (SM) is a flavonoid mixture with anti-oxidant and anti-inflammatory activities which explain its protective role against hepatic and renal injuries. However, its impact on gastric ulcer has not yet been elucidated. Thus we went further to investigate the potential protective effects of SM against indomethacin-induced gastric injury in rats. Pretreatment with SM (50 mg/kg orally) attenuated the severity of gastric mucosal damage as evidenced by decreasing ulcer index (UI) and ulcer score, improvement of disturbed histopathologicl features to be insignificant with those induced by the reference anti-ulcer drug. Pretreatment with SM also suppressed gastric inflammation by decreasing myeloperoxidase activity, tumer necrosis factor-α (TNF- α) and interleukin 6 (IL6) levels along with nuclear factor kappa B p65 (NF-κB) expression. Meanwhile, SM prevent gastric oxidative stress via inhibition of lipid peroxides formation, enhancement of glutathione peroxidase, superoxide dismutase activities and up-regulation of nuclear factor-erythroid-2-related factor 2 (Nrf2), the redox-sensitive master regulator of oxidative stress signaling. In conclusion, the results herein revealed that SM has a gastro-protective effect which is mediated via suppression of gastric inflammation, oxidative stress, increased the anti-oxidant and the cyto-protective defense mechanisms.