Gastric Mucosal Cell Apoptosis Research Articles

Integrated Approaches Revealed the Therapeutic Mechanisms of Zuojin Pill Against Gastric Mucosa Injury in a Rat Model with Chronic Atrophic Gastritis.

The Zuojin Pill (ZJP) is widely used for treating chronic atrophic gastritis (CAG) in clinical practice, effectively ameliorating symptoms such as vomiting, pain, and abdominal distension in patients. However, the underlying mechanisms of ZJP in treating CAG has not been fully elucidated. This study aimed to clarify the characteristic function of ZJP in the treatment of CAG and its potential mechanism. The CAG model was established by alternant administrations of ammonia solution and sodium deoxycholate, as well as an irregular diet. Therapeutic effects of ZJP on body weight, serum biochemical indexes and general condition were analyzed. HE staining and AB-PAS staining were analyzed to characterize the mucosal injury and the thickness of gastric mucosa. Furthermore, network pharmacology and molecular docking were used to predict the regulatory mechanism and main active components of ZJP in CAG treatment. RT-PCR, immunohistochemistry, immunofluorescence and Western blotting were used to measure the expression levels of apoptosis-related proteins, gastric mucosal barrier-associated proteins and PI3K/Akt signaling pathway proteins. The results demonstrated that ZJP significantly improved the general state of CAG rats, alleviated weight loss and gastric histological damage and reduced the serum biochemical indicators. Network pharmacology and molecular docking found that ZJP in treating CAG by inhibiting inflammation, suppressing apoptosis, and protecting the gastric mucosal barrier via the PI3K/Akt signaling pathway. Further experiments confirmed that ZJP obviously modulated the expression of key proteins involved in gastric mucosal cell apoptosis, such as Bax, Bad, Apaf-1, cleaved-caspase-3, cleaved-caspase-9, Cytochrome C, Bcl-2, and Bcl-xl. Moreover, ZJP significantly reversed the protein expression of Occludin, ZO-1, Claudin-4 and E-cadherin. Our study revealed that ZJP treats CAG by inhibiting the PI3K/Akt signaling pathway. This research provided a scientific basis for the rational use of ZJP in clinical practice.

Xiaojianzhong decoction attenuates aspirin-induced gastric mucosal injury via the PI3K/AKT/mTOR/ULK1 and AMPK/ULK1 pathways

Context Xiaojianzhong decoction (XJZD), classically prescribed in Chinese medicine, has protective and healing effects on gastric mucosal injury. However, the exact mechanism behind this effect remains unclear. Objective To investigate the effect of XJZD on gastric mucosal injury and explore its underlying mechanisms. Materials and methods C57BL/6 mice were randomized into six groups (n = 10): the control group receiving sterile water, the model (aspirin 300 mg/kg), the XJZD high-dose (12 g/kg), XJZD medium-dose (6 g/kg), XJZD low-dose (3 g/kg) and omeprazole (20 mg/kg) groups, by gavage daily for 14 days. The area of gastric mucosal injury, mucosal injury index and degree of histopathological damage were analysed. Gastric mucosal epithelial cell apoptosis was detected. Epithelial cell autophagy was observed. The expression levels of tight junction proteins and proteins related to apoptosis, autophagy and the pentose phosphate pathway were analysed. Results The results showed that after treatment with XJZD (12, 6 and 3 g/kg), the mucosal injury area was reduced (83.4%, 22.6% and 11.3%), the expression level of ZO-1 and occludin was up-regulated, the apoptosis rate of epithelial cells was reduced (40.8%, 25.4% and 8.7%), the expression of autophagy-related proteins LC3 and Beclin1 was decreased and the expression of p62 was increased, the PI3K/AKT/mTOR/ULK1(ser757) signalling pathway was activated, and the AMPK/ULK1(ser317) signalling pathway was inhibited. In addition, XJZD can antagonize the imbalance of redox homeostasis caused by aspirin and protect the gastric mucosa. Discussion and conclusions XJZD protects against aspirin-induced gastric mucosal injury, implying it to be a potential therapeutic agent.

Wei-Tong-Xin ameliorated cisplatin-induced mitophagy and apoptosis in gastric antral mucosa by activating the Nrf2/HO-1 pathway.

Wei-Tong-Xin (WTX) originated from the famous ancient Chinese formula "Wan Ying Yuan", recorded in the ancient Chinese medicine book "Zhong Zang Jing" by Hua Tuo. As "Jun" drugs, Dahuang and Muxiang have the effects of clearing heat and expelling fire, reducing food retention, regulating Qi and relieving pain. As "Chen" drug, Qianniuzi has the effect of assisting "Jun" drugs. Zhuyazao and Gancao, as "Zuo-Shi" drugs, can reduce toxicity and modulate the medicinal properties of other herbs. The present study aimed to investigate the effect and mechanism of WTX on the oxidative stress of gastric antrum mucosa in mice with cisplatin (CIS)-induced dyspepsia. AND. A variety of experimental methods, including western blot, qRT-PCR, immunofluorescence and immunohistochemistry were performed in vivo and in vitro. In vivo, WTX restored the number and function of interstitial cells of Cajal (ICCs), accompanied by the inhibition of lipid peroxidation. Moreover, WTX inhibited the activation of Parkin-dependent mitophagy and apoptosis. In vitro, WTX activated the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway and inactivated mitophagy in GES-1cells. To explore the role of Nrf2 in WTX's improvement of CIS-induced cell damage, Nrf2 inhibitor ML385 was used in cell experiments. We found that ML385 counteracted the regulation of WTX on mitophagy and apoptosis. Finally, N-acetylcysteine (NAC), a reactive oxygen species (ROS) scavenger, was applied in our experiments, and the results suggested that WTX suppressed the CIS-induced apoptosis via mitochondrial pathway. The above results, for the first time, indicated that WTX inhibited mitophagy and apoptosis of gastric antral mucosal cells induced by CIS through the Nrf2/HO-1 signaling pathway.

FTO-mediated m6A modification promotes malignant transformation of gastric mucosal epithelial cells in chronic Cag A+ Helicobacter pylori infection.

Cag A+ Helicobacter pylori chronic infection cause malignant transformation of the human gastric mucosa. N6-methyladenosine (m6A) modifications are the most common and abundant mRNA modifications and one of the pathways affecting tumorigenicity and tumor progression. However, the role of m6A modification in the process of chronic H. pylori infection leading to malignant transformation of gastric mucosa is unclear. In this study, we used Cag A- and Cag A+H. pylori chronic infection to establish cellular models in GES-1 cells and analyzed the cellular morphology, proliferation, apoptosis, invasiveness and tumorigenicity of gastric mucosal epithelial cells. The m6A expression levels of GES-1 cells after chronic infection with Cag A- and Cag A+H. pylori were examined, and modifying effect of FTO (the fat mass and obesity-associated protein) on CD44 was verified by MeRIP-qPCR. Finally, the FTO expression changes and m6A expression levels were further validated in clinical gastric cancer tissues. Chronic Cag A+H. pylori-infected GES-1 cells exhibit altered cell morphology, apoptosis inhibition, abnormal proliferation, enhanced migration, colony formation, and increased stem cell-like properties. Meanwhile, FTO and CD44 expression was enhanced, and FTO may induce malignant transformation of gastric mucosa by regulating CD44 mRNA m6A methylation modifications. We verified the effect of chronic stimulation of Cag A+H. pylori on malignant transformation of gastric mucosal epithelium. revealing the possibility of FTO in promoting malignant transformation of gastric mucosa by modifying CD44 mRNA methylation, suggesting that FTO expression is a potential molecule for malignant transformation of gastric mucosal epithelial cells.

Curculigoside attenuates Helicobacter pylori-induced inflammation and apoptosis of gastric mucosal epithelial cells via NF-κB pathway

Purpose: To investigate the possible effects and mechanisms of action of curculigoside (Cur) on gastric ulcers.
 Methods: Human gastric mucosal epithelial GES-1 cells were infected with Helicobacter pylori and then treated with Cur. Cell counting kit 8 (CCK-8), flow cytometry, and immunofluorescence assays were used to investigate the effect of Cur on cell viability and apoptosis after exposure to H. pylori. Inflammation status and reactive oxygen species (ROS) were assessed using enzyme-linked immunoassay (ELISA) and dichlorodihydrofluorescein (DCF) staining, respectively, while immunoblot and immunofluorescence assays were performed to determine the effect of Cur on the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway.
 Results: Cur significantly increased H. pylori-induced cell viability and inhibited H. pylori-induced inflammatory cytokine production (p < 0.01). Furthermore, Cur significantly suppressed H. pylori-induced ROS production and apoptosis (p < 0.01). Through the NF-κB pathway, Cur attenuated H. pylori-induced inflammation and apoptosis of gastric mucosal epithelial cells.
 Conclusion: In H. pylori infection, Cur treatment increases cell viability, reduces inflammatory cytokine production, suppresses ROS production, and inhibits apoptosis via NF-κB pathway. Further investigation using whole animal experiments would be needed to establish the role of Cur in the management of H. pylori-induced gastric ulcers.

CagA and VacA inhibit gastric mucosal epithelial cell autophagy and promote the progression of gastric precancerous lesions.

Cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA) are the keys to the pathogenic role of Helicobacter pylori and the high-risk factors for the progression of gastric precancerous lesions. Autophagy can stabilize the intracellular environment, resist Helicobacter pylori infection, prevent the accumulation of damaged DNA, and inhibit the proliferation of gastric precancerous variant cells. However, CagA and VacA can inhibit the activation of upstream signals of autophagy and the maturation of autophagy-lysosomes in various ways, thus inhibiting the autophagy of gastric mucosal cells in precancerous lesions of gastric cancer. This change can cause Helicobacter pylori to be unable to be effectively cleared by autophagy, so CagA and VacA can persist and promote the inflammation, oxidative stress, apoptosis of gastric mucosal tissue cells, and the glycolytic activity and proliferation of variant cells in gastric precancerous lesions and a series of malignant biological processes. In recent years, the research on drugs specifically inhibiting the activities of CagA and VacA has become a new direction for the prevention and treatment of Helicobacter pylori-related severe gastric diseases, and a variety of drugs or components that can precisely and effectively regulate the factors for the treatment of gastric precancerous lesions are emerged, which opens a new strategy for the treatment of gastric precancerous lesions in the future.

Astragalus polysaccharide inhibits apoptosis and inflammation to alleviate chronic atrophic gastritis through NF-κB signaling pathway in rats

Chronic atrophic gastritis (CAG) is a process of inflammation characterized by injured gastric mucosal epithelium leading to reduction of mucosal glands, often accompanied by intestinal or pseudopyloric metaplasia. Astragalus polysaccharide (APS) is reported to improve gastric mucosal damage and inflammation, but its role in CAG remains elusive. Therefore, we intended to analyze the impact of APS on CAG and its potential mechanism to provide novel insight into the treatment for the disorder. After establishment of CAG model using MNNG method, the rats were administered Vitazyme (200 mg/kg), or low, moderate and high concentration of APS (20, 40, 60 mg/kg), respectively, with healthy rats as controls and some CAG rats untreated. After that, the rat gastric tissues were pathologically examined and ELISA, Western blot analysis and staining were carried out to assess the impact of treatment on inflammation and apoptosis Pathologically, APS treatment alleviated the pathological changes of CAG rats, reducing inflammatory cell infiltration and inflammation. Besides, APS significantly diminished the content of pro-inflammatory factors and decreased the level of gastrointestinal hormones. In the presence of APS, the apoptosis of gastric mucosal cells was inhibited and the p-NF-κB p65 and p-IKKα/β expression was decreased. Collectively, APS could mitigate inflammation and gastric mucosal damage in CAG, as it also suppresses the process of apoptosis and inactivates the NF-κB signaling pathway. In a word, APS treatment improves CAG via NF-κB pathway.

Hypoxia induced apoptosis of rat gastric mucosal cells by activating autophagy through HIF-1α/TERT/mTORC1 pathway

The pathogenesis of high altitude-related gastric mucosal injury remains poorly understood, this study aimed to investigate the role of autophagy in hypoxia-induced apoptosis of rat gastric mucosal cells. Rats were randomized into four groups which were maintained at an altitude of 400 m (P) or received no treatment (H), autophagy inducer rapamycin (H+AI) or autophagy inhibitor 3-MA (H+AB) at an altitude of 4,300 m for 1, 7, 14 and 21 days, respectively, and the morphology, ultrastructure, autophagy, and apoptosis of gastric mucosal tissues were examined. Gastric mucosal epithelial cells CC-R039 were cultured under conditions of normoxia, 2% O2 (hypoxia), or 2% O2+anti-mTORC1 for 0, 24, 48, and 72 h, respectively, and the autophagy and apoptosis were analyzed. CC-R039 cells were transfected with siHIF-1α, siTERT, or siRNA and the autophagy was examined. The results showed that the exposure to hypoxia increased the autophagy and apoptosis of gastric mucosal cells in rats, and apoptosis was aggravated by rapamycin treatment but alleviated by 3-MA treatment. Increased duration of hypoxia from 0 to 72 h could increase the autophagy and apoptosis but decrease the proliferation of gastric mucosal cells. Inhibition of mTORC1 with rapamycin led to further increase in apoptosis and even substantial cell death, and inhibition of HIF- 1α and TERT increased mTORC1 expression and reduced autophagy. Moreover, the inhibition of HIF-1α reduced TERT expression. In conclusion, hypoxia could induce apoptosis of rat gastric mucosal cells by activating autophagy through HIF-1α/TERT/mTORC1 pathway

MiR-877-5p targets PDK-1 to promote aspirin-induced apoptosis in gastric mucosal cells.

This study aimed to investigate the role of miR-877-5p in aspirin-induced gastric mucosal injury. MiRNA microarray analysis was performed using paired gastric mucosal samples to find differentially expressed miRNAs. miR-877-5p was selected for subsequent analyses. Used as a model system, gastric epithelial cells (GES-1) were transfected with miR-877-5p mimic/inhibitor, then treated with aspirin. The expression of miR-877-5p in GES-1 cells was examined using quantitative real-time PCR (qRT-PCR). Flow cytometry analysis was used to detect cell apoptosis. Western blot assay was used to measure the protein levels of PDK1. The interaction between miR-877-5p and PDK1 was determined by luciferase reporter assay. The expression of miR-877-5p in gastric mucosal injury samples was higher than that in normal samples. Also, depletion of miR-877-5p reduced the apoptosis of GES-1 cells. Luciferase reporting assay confirmed that PDK1 was a target gene of miR-877-5p. PDK1 inhibited the apoptosis of GES-1 cells treated by aspirin. Moreover, this inhibitory effect was abrogated after PDK1 knockdown. Downregulation of miR-877-5p reduced the apoptosis by targeting PDK1 in GES-1 cells treated by aspirin, indicating that miR-877-5p may be a potential therapeutic target for gastric mucosal injury caused by aspirin.

Effect of moxibustion and acupuncture on gastric mucosal cell apoptosis and expression of NF-κB, Bcl-2 in chronic atrophic gastritis rats

To observe the effect of moxibustion and acupuncture on apoptosis in gastric mucosal cell and expression of NF-κB, Bcl-2 in chronic atrophic gastritis (CAG) rats, so as to explore its mechanisms underlying improvement of CAG. Forty-eight male SD rats were randomly divided into normal, model, moxibustion and acupuncture groups, with 12 rats in each group. The CAG model was established by gavage of N-methyl-N'-nitro-N-nitroso-guanidine (MNNG) solution and irregular diet for 12 weeks. Moxibustion or acupuncture was applied to "Zusanli" (ST36) and "Zhongwan" (CV12) for 15 min, once daily for two weeks in the moxibustion or acupuncture group. The histopathological changes of the gastric mucosa were observed by HE staining. The apoptosis index of gastric mucosa was measured by TUNEL method. The gene expression levels of NF-κB and Bcl-2 were detected by real-time PCR. After modeling, the color of gastric mucosa was pale and dark, with low folds and significant bleeding points. The glands in lamina propria were atrophied, arranged disorderly, and the numbers were significantly reduced, with inflammatory cells infiltrated. Those histopathological changes were evidently milder in the moxibustion and acupuncture groups. Compared with the normal group, the apoptosis index, NF-κB and Bcl-2 gene expression of the model group were significantly increased (P<0.01). After the treatment, the apoptosis index, NF-κB and Bcl-2 gene expression were significantly reduced in the moxibustion and acupuncture groups (P<0.05，P<0.01). The NF-κB expression was lower in the acupuncture group than that of moxibustion group (P<0.01). Moxibustion and acupuncture therapy can improve the injury of gastric mucosa in CAG rats, which may be associated with its function in down-regulating the expression of NF-κB and Bcl-2 genes in the gastric mucosa.

Research strategy thoughts about acupuncture-moxibustion treatment of chronic atrophic gastritis by suppressing apoptosis via circular RNA

Chronic atrophic gastritis (CAG) is a common digestive disease in clinic. Previous experimental and clinical studies have shown that acupuncture has a positive effect for CAG. Apoptosis of gastric mucosal tissue has been shown to play an important role in the process of gastric atrophy and possibly further carcinogenesis in CAG, and the circular RNA (circRNA), a novel class of non-coding RNA, has been confirmed to play a regulatory role in the downstream pathway of apoptosis by many stu-dies. Accumulated findings of experimental studies showed that acupuncture and moxibustion interventions could suppress apoptosis of the cultured human gastric mucosal epithelial cells and lower apoptotic index of gastric mucosal cells in CAG rats. Therefore, circRNA is likely to mediate the inhibitory effect of acupuncture and moxibustion on apoptosis of gastric mucosal epithelial cells in CAG. In this paper, we systematically summarized 1) the regulation of circRNA on apoptosis, 2) the apoptosis and pathological mechanism of CAG, 3) the effect of acupuncture on apoptosis, and proposed that circRNA is highly likely to be involved in the positive effect of acupuncture and moxibustion interventions for CAG. It is recommended that researches should further reveal the scientific basis of acupuncture and moxibustion therapies in the treatment of CAG by exploring the role of related circRNAs and their downstream target proteins in the gastric mucosal tissues.

Показатели пролиферации и апоптоза эпителиальных клеток слизистой оболочки желудка у коренных жителей Республики Тыва с Helicobacter pylori-позитивной язвенной болезнью двенадцатиперстной кишки

Показатели пролиферации и апоптоза эпителиальных клеток слизистой оболочки желудка у коренных жителей Республики Тыва с Helicobacter pylori-позитивной язвенной болезнью двенадцатиперстной кишки

The Effects of C‐Phycocyanin and Lycium barbarum Polysaccharides on Aspirin‐Induced Apoptosis in Rat Gastric Mucosal Cells

Non‐steroidal anti‐inflammatory drugs (NSAIDs) cause gastrointestinal injury through both topical and systemic effects, which may generate reactive oxygen species and lead to apoptosis. Aspirin, a NSAID, is widely used for cardio‐protection and causes gastrotoxicity in long‐term administration. C‐phycocyanin (CPC) is a biliprotein pigment of the blue‐green alga Spirulina platensis, and possesses antioxidant, anti‐inflammatory, and wound‐healing properties. Lycium barbarum polysaccharides (LBP) extracted from wolfberry act as an antioxidant and immunomodulator. This study investigated the effects of CPC and LBP on aspirin‐induced apoptosis in rat gastric mucosal RGM‐1 cells. Rat RGM‐1 cells were pretreated with different concentrations of CPC and/or LBP (100, 250, and 500 μg/mL) for 24 hours, and gastric damage was induced by 21 mM aspirin for 3 hours. Apoptotic protein expression was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blotting. The results showed that aspirin significantly increased c‐Jun N‐terminal kinase (JNK), p38 phosphorylation, and Bax expression, while LBP decreased JNK activation and Bax expression compared with aspirin treatment alone. However, CPC had no effects on these apoptotic markers. In conclusion, LBP may decrease aspirin‐induced apoptosis in rat gastric mucosal RGM‐1 cells by suppressing the activation of JNK signaling pathway.Support or Funding InformationThe study was supported by the Ministry of Science and Technology, Taiwan (grant no. MOST105‐2320‐B‐038‐036‐MY3).

Chronic CagA-positive Helicobacter pylori infection with MNNG stimulation synergistically induces mesenchymal and cancer stem cell-like properties in gastric mucosal epithelial cells.

A CagA-positive Helicobacter pylori (H. pylori) infection can cause malignant transformation of human gastric mucosal epithelial cells, and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) is a chemical carcinogen that induces gastric carcinogenesis. Whether this environmental chemocarcinogen may synergistically enhance the risk of H. pylori-infected gastric cancer remains unclear. In this study, we adopted a chronic CagA-positive H. pylori infection with or without MNNG coinduction to establish a cellular model in GES-1 cells and an animal model in C57BL/6J mice. The proliferation, cell phenotype, apoptosis, epithelial-mesenchymal transition (EMT), stemness and tumorigenicity of gastric mucosal epithelial cells were analyzed in vitro and in vivo. The results showed that chronic H. pylori-infected GES-1 cells displayed inhibited apoptosis, abnormal proliferation, enhanced invasion, and migration, increased EMT/mesenchymal phenotype, colony formation and stem cell-like properties, and enhanced tumorsphere-formatting efficiency as well as CD44 expression, a known gastric cancer stem cell (CSC) marker. MNNG synergistically promoted the above actions of chronic H. pylori infection. Further studies in chronic H. pylori-infected C57BL/6J mice models showed that an increased incidence of premalignant lesions in the gastric mucosa tissue of the H. pylori-infected mice had occurred, the mouse gastric mucosa cells exhibited similar mesenchymal and CSC-like properties in the above GES-1 cells, and precancerous lesions and EMT/CSC-like phenotypes were reinforced by the synergistic action of MNNG stimulation. H. pylori infection and/or MNNG induction were capable of causing enhanced expression and activation of Wnt2 and β-catenin, indicating that the Wnt/β-catenin pathway is involved in the actions of H. pylori and MNNG. Taken together, these findings suggest that chronic CagA-positive H. pylori infection with MNNG stimulation synergistically induces mesenchymal and CSC-like properties of gastric mucosal epithelial cells.

Effects of miR-101 on the proliferation and apoptosis of gastric mucosal epithelial cells via Nrf2/ARE signaling pathway.

The aim of this study was to investigate the effects of micro-ribonucleic acid (miR)-101 on the proliferation and apoptosis of gastric mucosal epithelial cells through nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway. Human gastric epithelial AGS (CRL-1739) cells were cultured in vitro. MiR-101 down-regulation or over-expression was achieved by transfection of inhibitors, or miRNA mimics, respectively. The apoptosis rate was detected by flow cytometry. Meanwhile, the targets of miR-101 were verified by the Dual-Luciferase reporter gene assay. Furthermore, the changes in protein levels were measured via Western blotting (WB). Up-regulation of miR-101 significantly promoted the apoptosis of gastric mucosal epithelial cells. The 3'-untranslated region (3'-UTR) of Nrf2 was highly conserved to combine with miR-101. The Luciferase reporter gene assay showed that transfection of miR-101 mimics could remarkably inhibit the relative Luciferase activity in cells. In addition, miR-101 overexpression markedly down-regulated the messenger RNA (mRNA) and protein expressions of Nrf2 in cells. MiR-101 plays an important role in regulating the proliferation and apoptosis of gastric mucosal epithelial cells by targeting the Nrf2-ARE signaling pathway.

胃上皮細胞表面でのFas抗原(CD95)の発現に対するHelicobacter pyloriと非ステロイド系抗炎症薬の相乗効果

胃上皮細胞表面でのFas抗原(CD95)の発現に対するHelicobacter pyloriと非ステロイド系抗炎症薬の相乗効果

Expression of apoptosis-associated microRNAs in ethanol-induced acute gastric mucosal injury via JNK pathway

MicroRNAs (miRNAs) have been shown to be closely associated with cellular apoptosis, but their involvement in response to ethanol-induced gastric mucosal epithelial cell apoptosis remains largely unknown. The purpose of this study was to investigate the expression profile of apoptosis-associated miRNAs in ethanol-induced acute gastric mucosal injury and the mechanisms underlying injury. Gastric mucosal injury was induced in rats by oral administration of ethanol, and gastric tissues were collected for analysis of gastric ulcer index, apoptosis ratio, caspase-3 activity, and miRNAs expression. Cell cultures of human gastric mucosal epithelial cells (GES-1) were incubated with ethanol to induce apoptosis. Mimics or inhibitors of miRNAs or c-Jun N-terminal kinase (JNK) inhibitor were added to the cell culture medium. GES-1 cells were collected for analysis of apoptosis ratio, caspase-3 activity, miRNAs expression, and protein phosphorylation levels of JNK, p38 mitogen-activated protein kinase (p38MAPK), or extracellular signal-regulated kinase (ERK). In the animal experiments, gastric ulcer index, cellular apoptosis, and caspase-3 activity were significantly increased, accompanied by up-regulation of miR-145 and down-regulation of the microRNAs miR-17, miR-19a, miR-21, miR-181a, and miR-200c. In the human cell culture experiments, the anti-apoptotic effects of miR-19a and miR-21 or pro-apoptotic effect of miR-145 were confirmed by their corresponding mimics or inhibitor; the ethanol-induced GES-1 apoptosis as well as the changes in miRNAs expression were significantly attenuated in the presence of JNK inhibitor. These results demonstrated that miR-145, miR-19a, and miR-21 were the apoptosis-associated miRNAs in gastric mucosal epithelial cells. The regulation of expression of these 3 miRNAs in ethanol-induced GES-1 apoptosis involved the JNK pathway.

γ‐aminobutyric acid‐mediated neurotransmission in cerebellar–hypothalamic circuit attenuates gastric mucosal injury induced by ischemia‐reperfusion

Excessive greater splanchnic nerve (GSN) activation contributes to the progression of gastric ischemia-reperfusion (GI-R) injury. This study was designed to investigate the protective mechanism of cerebellar fastigial nucleus (FN) stimulation against GI-R injury. The GI-R injury model was induced in rats by clamping the celiac artery for 30 min, and then reperfusion for 30 min, 1, 3, 6, or 24 h, respectively. Microinjection of L-Glu (3, 6, 12 μg) into the FN dose-dependently attenuated GI-R injury and GSN activity. In addition, there was an enhancement of gastric mucosal blood flow in GI-R rats. Pretreatment with the glutamic acid decarboxylase antagonist into the FN, the GABAA receptor antagonist into the lateral hypothalamic area or lesion of superior cerebellar peduncle all reversed the protective effects of the FN stimulation. Furthermore, the FN stimulation reduced the TUNEL-positive gastric mucosal cell and Bax-positive gastric mucosal cell in GI-R rats. These results indicate that the protective effects of the FN stimulation against GI-R injury may be mediated by attenuation of the excessive GSN activation, gastric mucosal cell apoptosis, and Bax expression in GI-R rats.

The Impact of Asymmetric Dimethylarginine (ADAMA), the Endogenous Nitric Oxide (NO) Synthase Inhibitor, to the Pathogenesis of Gastric Mucosal Damage

This review was designed to provide an update on the role of asymmetric arginine (ADMA), the endogenous inhibitor of nitric oxide (NO) synthase in the pathophysiology of the upper gastrointestinal (GI) tract. Numerous studies in the past confirmed that NO is a multifunctional endogenous gas molecule involved in most of the body organs’ functional and metabolic processes including the regulation of gastrointestinal (GI) secretory functions, motility, maintenance of GI integrity, gastroprotection and ulcer healing. NO is metabolized from L-arginine by enzymatic reaction in the presence of constitutive NO synthase. In upper GI tract, NO acts as a potent vasodilator known to increase gastric mucosa blood flow, regulates the secretion of mucus and bicarbonate, inhibits the gastric secretion and protects the gastric mucosa against the damage induced by a variety of damaging agents and corrosive substances. In contrast, ADMA first time described by Vallance and coworkers in 1992, is synthesized by the hydrolysis of proteins containing methylated arginine amino acids located predominantly within the nucleus of cells. This molecule has been shown to competitively inhibit NO synthase suggesting its regulatory role in the functions of vascular endothelial cells and systemic circulation in humans and experimental animals. Nowadays, ADMA is a potentially important risk factor for coronary artery diseases and a marker of cardiovascular risk. Increased plasma levels of ADMA have been documented in several conditions that are characterized by endothelial dysfunction, including hypertension, hypercholesterolemia, hyperglycemia, renal failure and tobacco exposure. The role of ADMA in other systems including GI-tract has been so far less documented. Nevertheless, ADMA was shown to directly induce oxidative stress and cell apoptosis in gastric mucosal cells in vitro and to contribute to the inflammatory reaction associated with major human pathogen to gastric mucosa, Helicobacter pylori (H.pylori). Infection of gastric mucosa with this germ or H. pylori water extract led to marked increase in the plasma concentration of ADMA and significantly inhibited bicarbonate secretion, considered as one of the important components of upper GI-tract defense system. When administered to rodents, ADMA aggravated gastric mucosal lesions injury induced by cold stress, ethanol and indomethacin and this worsening effect on gastric lesions was accompanied by the significant increase in the plasma level of ADMA. This exaggeration of gastric lesions by ADMA was coincided with the inhibition of NO, the suppression of gastric blood flow and excessive release of proinflammatory cytokine TNF-α. This metabolic analog of L-arginine applied to rats was exposed to water immersion and restraint stress and ischemiareperfusion, causing an elevation of plasma levels of ADMA and gastric MDA content, which is the marker of lipid peroxidation. These effects, including the rise in the plasma levels of ADMA in rats with stress and ischemia-reperfusion-induced gastric lesions, were attenuated by concomitant treatment with L-arginine, the substrate for NO-synthase, and superoxide dismutase (SOD), a reactive oxygen metabolite scavenger added to ADMA. We conclude that ADMA could be considered as an important factor contributing to the pathogenesis of gastric mucosal damage and inflammatory reaction in H. pylori-infected stomach due to inhibition of NO, suppression of GI microcirculation, and the proinflammatory and proapoptotic actions of this arginine analog.

Lateral hypothalamic area mediated the protective effects of microinjection of glutamate into interpositus nucleus on gastric ischemia-reperfusion injury in rats

We investigated the protective effects of chemical stimulation of cerebellar interpositus nucleus (IN) on gastric ischemia-reperfusion injury (GI-RI) and its possible regulatory mechanisms in rats. Gastric mucosal damage index (GMDI) indicated the severity of gastric mucosal injuries. Transferase dUTP nick end labeling (TUNEL) staining and proliferating cell nuclear antigen (PCNA) were performed to assess gastric mucosal cell apoptosis and proliferation. Microinjection of glutamate into IN markedly attenuated GI-RI. Either chemical lesion of IN or electrical ablation of the decussation of superior cerebellar peduncle (DSCP) obviously aggravated GI-RI. The protective effects of IN were reversed with the pretreatments of microinjection of 3-mercaptopropionic acid into IN or Bicuculline into lateral hypothalamic area (LHA), individually. The discharge frequency and intensity of greater splanchnic nerve (GSN) decreased and gastric mucosal blood flow increased after chemical stimulation of IN. The apoptosis of positive cells of gastric mucosa was decreased by chemical stimulation of IN, whereas proliferation increased. The gastric juice volume, acidity, and total acid output were all decreased after the chemical stimulation of IN. These results indicated that IN participates in regulation of GI-RI and is a specific area in central nervous system for exerting protective effects on GI-RI. DSCP, LHA and GSN may involve in this process. Apoptosis and proliferation may mediate this protective process in rats too.