Role of prostaglandins and nitric oxide in gastric damage induced by metamizol in rats

The active components and potential mechanisms of Wuji Wan in the treatment of ethanol-induced gastric ulcer: An integrated metabolomics, network pharmacology and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Wuji Wan (WJW) is a traditional Chinese medicine formula that can be found in the "Prescriptions of Taiping Benevolent Dispensary" that has been employed in treating gastric discomfort, burning epigastric pain, and gastric reflux for hundreds of years and has shown promise for treating gastric ulcers (GUs). However, the active components and mechanism of action against GUs remain unclear.

AIM OF THE STUDY

The aim of this study was to explore the active components of WJW and elucidate the underlying mechanism involved in treating GUs.

MATERIALS AND METHODS

Initially, cell viability was measured by a cell counting kit 8 (CCK-8) assay to evaluate the efficacy of WJW-containing serum in vitro. The gastric ulcer index, ulcer inhibition rate, hematoxylin and staining (H&E), and periodic acid-Schiff (PAS) staining were used to evaluate the therapeutic effect of WJW in vivo. Subsequently, the levels of inflammatory factors and oxidative stress factors were determined using an enzyme-linked immunosorbent assays (ELISA) on in vitro and in vivo samples. Additionally, UPLC-Q Exactive Plus Orbitrap HRMS was used to analyze the components that were absorbed into the blood of WJW and its metabolites. Network pharmacology and metabolomics were subsequently used to identify the targets and pathways. Real-time quantitative PCR (RT‒qPCR) and Western blotting were used to verify the mRNA and protein levels of the key targets and pathways. Finally, the active components were identified by molecular docking to verify the binding stability of the components and key targets.

RESULTS

WJW-containing serum ameliorated ethanol-induced damage in GES-1 cells and promoted cell healing. WJW-containing serum reduced IL-6, TNF-α, MDA, and LDH levels while increasing IL-10, SOD, and T-AOC levels in the cells. Moreover, WJW treatment resulted in decreased IL-6, TNF-α, and MDA levels and increased IL-10, SOD, PGE2, and NO levels in GUs rats. In addition, eight components of WJW were absorbed into the blood. The network pharmacology results revealed 192 common targets for blood entry components and GUs, and KEGG analysis revealed that apoptosis signaling pathways were the main pathways involved in WJW activity against GUs. Metabolomic screening was used to identify 13 differential metabolites. There were 23 common targets for blood entry components, GUs, and differential metabolites, with the key targets TNF (TNF-α), AKT1, PTGS2 (COX2) and MAPK1. WJW significantly inhibited the expression of Bax, Caspase-9, Caspase-3, cleaved Caspase-9, cleaved Caspase-3, TNF-α, COX2, and p-p44/42 MAPK while promoting the expression of Bcl-2 and p-AKT1. Molecular docking revealed that the active components of WJW for the treatment of GUs are berberine, palmatine, coptisine, evodiamine, rutaecarpine, evocarpine, and paeoniflorin.

CONCLUSIONS

WJW treatment reduces inflammation and oxidative stress injury and inhibits apoptosis signaling pathways. The main active components are berberine, palmatine, coptisine, evodiamine, rutaecarpine, evocarpine, and paeoniflorin. In this paper, we provide a new strategy for exploring the active components of traditional Chinese medicine formulas for the treatment of diseases based on target mechanisms.

The ameliorative impacts of wheat germ oil against ethanol-induced gastric ulcers: involvement of anti-inflammatory, antiapoptotic, and antioxidant activities

This study examined if wheat germ oil (WGO) has gastroprotective impacts against ethanol-induced gastric ulcer in rats. Rats were assigned into control, WGO, ethanol, omeprazole + ethanol, and WGO + ethanol. WGO prevented gastric ulceration and damage induced by ethanol, the same effect induced by omeprazole, a widely known medication used for gastric ulcer treatment. WGO reduced gastric ulcer index, nitric oxide, and malondialdehyde levels in the stomach. WGO boosted the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), Bcl2, and the antioxidants. WGO showed inflammatory and anti-inflammatory impacts through the control of interleukin (IL)-1β, Tumor necrosis factor alpha (TNF-α), and IL-10 that were altered in ethanol-administered rats. Ethanol up-regulated caspase-3 and nuclear factor-kappa B (NF-kB) expression and showed histopathological changes such as necrosis and mucosal degeneration that were mitigated by pre-administration of WGO. Moreover, WGO decreased gastric immunoreactivity of NF-kB and increased transforming growth factor beta-1 (TGF-β1) that were associated with upregulation of Nrf2, heme oxygenase-1 (HO-1), and antioxidant expression and production. In conclusion, WGO reduced ethanol-induced stomach toxicity by regulating genes involved in oxidative stress, inflammation, and apoptotic/antiapoptotic pathways.

Gastroprotective Effect of Sinapic Acid on Ethanol-Induced Gastric Ulcers in Rats: Involvement of Nrf2/HO-1 and NF-κB Signaling and Antiapoptotic Role

Background: In the current study, we evaluated the therapeutic potential of sinapic acid (SA) in terms of the mechanism underlying its gastroprotective action against ethanol-induced gastric ulcers in rats.

Methods: These effects were examined through gross macroscopic evaluation of the stomach cavity [gastric ulcer index (GUI)], alteration in pH, gastric juice volume, free acidity, total acidity, total gastric wall mucus, and changes in PGE2. In addition, we evaluated lipid peroxidation (malondialdehyde), antioxidant systems (catalase and glutathione), inflammatory markers [tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and myeloperoxidase (MPO)], apoptotic markers (caspase-3, Bax, and Bcl-2), nuclear factor-κB [NF-κB (p65)], NO levels, and histopathological staining (H and E and PAS).

Results: In rats with ethanol-induced ulcers, pre-treatment with SA (40 mg/kg p. o.) decreased the sternness of ethanol-induced gastric mucosal injuries by decreasing the GUI, gastric juice volume, free acidity, and total acidity. In addition, the pH and total gastric mucosa were increased, together with histopathological alteration, neutrophil incursion, and increases in PGE2 and NO₂. These effects were similar to those observed for omeprazole, a standard anti-ulcer drug. SA was shown to suppress gastric inflammation through decreasing TNF-α, IL-6, and MPO, as well as curbing gastric oxidative stress through the inhibition of lipid peroxidation (MDA) and restoration of depleted glutathione and catalase activity. SA inhibited Bcl-2-associated X (Bax) and caspase-3 activity, and restored the antiapoptotic protein Bcl-2; these findings indicate the antiapoptotic potential of SA, leading to enhanced cell survival. SA also repressed NF-κB signaling and increased IκBα. Moreover, SA upregulated the nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), thereby restoring depleted antioxidant defense enzymes and implicating the NRF2/HO-1 signaling pathways.

Conclusion: These results suggest that the prophylactic administration of SA (40 mg/kg) can ameliorate ethanol-induced gastric ulcers in rats primarily via the modulation of Nrf2/HO-1 and NF-κB signaling and subsequent enhancement of cell viability.

The Contribution of Specific and Nonspecific Biomarkers in Diagnosis of Equine Gastric Ulcer Syndrome (EGUS) Under Field Condition

The aim of this study is to investigate the diagnostic efficiency of gastrin, pepsinogen, proinflammatory cytokines (TNF-α, IL-6), and oxidative stress biomarkers in horses with equine gastric ulcer syndrome (EGUS). Thirty horses diagnosed with gastroscopic EGUS and 15 clinically healthy horses were selected for this study. The serum levels of gastrin, pepsinogen showed nonsignificant changes in horses with EGUS when compared with healthy horses. The serum levels of TNF-α, IL-6 revealed a significant increase in horses with EGUS when compared with healthy ones. Oxidative stress is evident in horses with EGUS in comparison with healthy horses as detected by higher levels of malondialdehyde (MDA) and decreased serum levels of total antioxidant capacity (TAC), Superoxide dismutase (SOD), glutathione (GSH), and nitric oxide (NO). MDA and TNF-α showed better sensitivity and specificity than IL-6 in distinguishing horses with EGUS from control horses. Conclusively, examination of serum gastrin and pepsinogen levels had a limited value in diagnosis of EGUS in horses under investigation. Moreover, this study showed that oxidative stress is evident in horses with EGUS. Higher levels of TNF-α and IL-6 indicate their role in EGUS pathogenesis in horses. Finally, MDA, TNF-α, and IL-6 could be used as biological markers for preliminary screening of horses with EGUS. Gastroscopy still accredited as the "gold standard" for diagnosis EGUS.

Effects of dipyrone on the digestive tract

Dipyrone (metamizole), acting through its main metabolites 4-methyl-amino-antipyrine and 4-amino-antipyrine, has established analgesic, antipyretic, and spasmolytic pharmacological effects, which are mediated by poorly known mechanisms. In rats, intravenously administered dipyrone delays gastric emptying (GE) of liquids with the participation of capsaicin-sensitive afferent fibers. This effect seems to be mediated by norepinephrine originating from the sympathetic nervous system but not from the superior celiac-mesenteric ganglion complex, which activates β2-adrenoceptors. In rats, in contrast to nonselective non-hormonal anti-inflammatory drugs, dipyrone protects the gastric mucosa attenuating the development of gastric ulcers induced by a number of agents. Clinically, it has been demonstrated that dipyrone is effective in the control of colic-like abdominal pain originating from the biliary and intestinal tracts. Since studies in humans and animals have demonstrated the presence of β2-adrenoceptors in biliary tract smooth muscle and β2-adrenoceptor activation has been shown to occur in dipyrone-induced delayed GE, it is likely that this kind of receptors may participate in the reduction of smooth muscle spasm of the sphincter of Oddi induced by dipyrone. There is no evidence that dipyrone may interfere with small bowel and colon motility, and the clinical results of its therapeutic use in intestinal colic appear to be due to its analgesic effect.

Effect of orexin-a on ischemia-reperfusion-induced gastric damage in rats

BACKGROUND

Orexins are involved in the regulation of sleeping behavior and energy homeostasis, and they are also implicated in the regulation of gastrointestinal functions. Previous reports have demonstrated the expression of orexin receptors in the gastrointestinal system. The aim of this study was to investigate the gastroprotective effect of orexin-A in ischemia-reperfusion-induced gastric mucosal injury.

METHODS

The gastric ischemia-reperfusion model was established by clamping the celiac artery for 30 min and reperfusing for 60 min. Orexin-A was administered in doses of 500 pmol.kg(-1).min(-1) by infusion throughout the ischemia-reperfusion period. The mean lesion area, gastric prostaglandin E2 and mucus content, myeloperoxidase activity, and production of thiobarbituric acid reactive substances were measured.

RESULTS

Orexin-A significantly attenuated the ischemia-reperfusion-induced gastric lesions and also decreased myeloperoxidase activity and the thiobarbituric acid reactive substances content in gastric mucosa of rats exposed to ischemia-reperfusion. However, the decline in gastric prostaglandin E2 and mucus content was not restored by orexin-A treatment.

CONCLUSIONS

Orexin-A exhibited a gastroprotective effect against ischemia-reperfusion-induced lesions by decreasing neutrophil activation and lipid peroxidation.

Dipyrone elicits substantial inhibition of peripheral cyclooxygenases in humans: new insights into the pharmacology of an old analgesic

Dipyrone (INN, metamizol) is a common analgesic used worldwide. Its widespread prescription or over-the-counter use in many countries (e.g., Brazil, Israel, Mexico, Russia, Spain) requires insight into its mode of action. This study therefore addressed the impact of its metabolites 4-methyl-amino-antipyrine (MAA) and 4-amino-antipyrine (AA) on peripheral cyclooxygenases (COX). Pharmacokinetics of metabolites and ex vivo COX inhibition were assessed in five volunteers receiving dipyrone at single oral doses of 500 or 1000 mg. Coagulation-induced thromboxane B2 formation and lipopolysaccharide-induced prostaglandin E2 synthesis were measured in vitro and ex vivo in human whole blood as indices of COX-1 and COX-2 activity. In vitro, metabolites elicited no substantial COX-1/COX-2 selectivity with MAA (IC50=2.55 micromol/L for COX-1; IC50=4.65 micromol/L for COX-2), being approximately 8.2- or 9-fold more potent than AA. After administration of dipyrone, MAA plasma concentrations remained above the IC50 values for each isoform for at least 8 h (500 mg) and 12 h (1000 mg) postdose. COX inhibition correlated with MAA plasma levels (ex vivo IC50 values of 1.03 micromol/L [COX-1] and 0.87 micromol/L [COX-2]). By contrast, plasma peak concentrations of AA after the 1000 mg dose were 2.8- and 6.5-fold below its IC50 values for COX-1 and COX-2, respectively. Maximal inhibitions of COX-1 and COX-2 were 94% and 87% (500 mg), 97% and 94% (1000 mg). Taken together, dipyrone elicits a substantial and virtually equipotent inhibition of COX isoforms via MAA. Given the profound COX-2 suppression by dipyrone, which was considerably above COX-2 inhibition by single analgesic doses of celecoxib and rofecoxib, a significant portion of its analgesic action may be ascribed to peripheral mechanisms. In view of the observed COX-1 suppression, physicochemical factors (lack of acidity) rather than differential COX-1 inhibition may be responsible for dipyrone's favorable gastrointestinal tolerability compared with acidic COX inhibitors.

Role of nitric oxide in the protective effect of rabeprazole on gastric mucosal lesions in rats

AIM: To explore the role of nitric oxide (NO) in the protective effect of rabeprazole on the gastric mucosal lesions in rats.

METHODS: Before gastric mucosal lesion was made in rats by pure alcohol, rabeprazole (20 mg/kg) was administered into the gastric chamber and Nw-nitro-l-arginine methyl ester (l-NAME, 4 mg/kg), l-arginine (250 mg/kg) and d-arginine (250 mg/kg) were injected into the vein. Gastric mucosal blood flow (GMBF) was assessed with laser Doppler flowmetry (LDF); gastric mucosal and serum NO^-₂/NO^-₃ were measured by cadmium granulation reduction and colorimetric method; and the changes of ulcer index and the severity of tissue necrosis as well as neutrophil infiltration were observed.

RESULTS: The Ulcer index of the rabeprazole group was markedly lower than that in the controls (5.5 ± 0.5 vs 25.2 ± 2.3, P < 0.01), and the degrees of tissue necrosis and neutrophil infiltration were significantly milder (necrosis ++ - +++/≤+: 1/9 vs 8/2, P < 0.01; infiltration ++ - +++/≤+: 3/7 vs 9/1, P < 0.01). The protective effect of rabeprazole was significantly decreased by prior administration of l-NAME. The inhibitory effect of l-NAME was antagonized by prior administration of l-arginine, but not d-arginine. Rabeprazole administered into the gastric chamber obviously increased GMBF, gastric mucosal and serum NO^-₂/NO^-₃, which was prevented by pretreatment with l-NAME, but the antisecretory effect of rabeprazole was not affected by l-NAME.

CONCLUSION: Rabeprazole can exert important protection against gastric mucosal lesions in rats mediated by nitric oxide, and the action of rabeprazole against gastric acid secretion contributes little to the protective effect.

Dipyrone and aminopyrine are effective scavengers of reactive nitrogen species

Reactive nitrogen species (RNS), namely nitric oxide (NO*) and peroxynitrite (ONOO-) are produced in the inflammatory sites and may contribute to the deleterious effects of inflammation. The aim of the present study was to evaluate the putative scavenging effect of a particular group of non-steroidal anti-inflammatory drugs (NSAIDs), the pyrazolone derivatives dipyrone, aminopyrine, isopropylantipyrine, and antipyrine against RNS, using in vitro non-cellular screening systems. The results obtained showed that dipyrone and aminopyrine were highly potent scavengers of NO* and ONOO- while antipyrine exerted little effect and isopropylantipyrine no effect whatsoever against these two RNS and that, in the presence of bicarbonate, the scavenging potencies of both dipyrone and aminopyrine were slightly decreased. It could thus be inferred that the observed scavenging effects may be of therapeutic benefit for patients under anti-inflammatory treatment with dipyrone and aminopyrine in the case of overproduction of RNS. On the other hand, the possible depletion of physiological NO* concentrations, namely at the gastrointestinal tract as well as the formation of reactive derivatives of aminopyrine and/or dipyrone, resulting from their reaction with RNS, may otherwise be harmful for these patients.

The cytoprotective effect of a nitric oxide donor drug on gastric mucous membrane of rats treated with ketoprofen, a non-steroidal anti-inflammatory drug

BACKGROUND: Non-steroidal anti-inflammatory drugs are considered today a very important group of medication, with a wide variety of therapeutic use, in different areas of modern medicine. Despite their beneficial effects on the patient, these drugs show a high incidence of side effects, mainly in the gastrointestinal tract. The physiopathological mechanisms of non-steroidal anti-inflammatory drugs induced lesions and the gastric mucosa defense mechanism became an important source for medical research, especially those which try to evaluate the role of nitric oxide as a cytoprotective agent. AIM: To define a possible cytoprotective effect of a nitric oxide donor, isosorbide dinitrate, on the gastric mucous of rats submitted to non-steroidal anti-inflammatory drugs ketoprofen treatment. METHODS: Adult male Wistar rats, previously submitted to starvation for 24 hours and divided in three groups: group I (standard): animals that received isotonic saline solution intragastric by gavage and intravenous. Group II (control-ketoprofen): animals that received isotonic saline solution intragastric by gavage and ketoprofen intravenous. Group III (nitrate/ketoprofen): animals that received 2mM solution of isosorbide dinitrate intragastric by gavage and ketoprofen intravenous. Later on, these animals were sacrificed and had their stomach removed and submitted to macroscopical, microscopical and biochemical studies. The evaluated parameters were: a) gastric lesion index; b) gastric mucous layer thickness; c) gastric tissue nitrate/nitrite (NOx) concentration and d) gastric tissue malondialdehyde concentration. RESULTS: a) Gastric lesion index evaluation showed a smaller statistically significant incidence on the animals of group III; b) group III showed a thicker mucous layer, which also was statistically significant, when compared to group II; c) the variation on tissue nitrate/nitrite concentration was similar in all three groups, without statistical significance when compared to each other. CONCLUSION: Isosorbide dinitrate has a cytoprotective activity on the gastric mucosa of rats submitted to ketoprofen action.

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Protective effect of pantoprazole on gastric mucosal lesions in rats and its mechanism

AIM: To explore the protective effect of pantoprazole on the gastric mucosal lesions in rats and its related mechanism.

METHODS: Before the gastric mucosal lesion was in-duced by pure alcohol, the rats were intravenously injected with pantoprazole (20 mg/kg), Nω-nitro-L-arginine methyl ester (L-NAME, 4 mg/kg), and L-arginine (250 mg/kg). The gastric mucosal blood flow (GMBF) was detected by laser Doppler flowmetry (LDF), and the level of NO^-₂/NO^-₃ in the gastric mucosa and serum was measured by cadmium granulation reduction and colorimetric method. The ulcer index (UI), the severity of tissue necrosis, and neutrophils infiltration were observed.

RESULTS: Compared with that in the control group, the UI was significantly decreased (5.7±2.1 vs 25.4±2.5, P <0.01), and the degrees of tissue necrosis and neutrophils infiltration were markedly lightened. The protective effect of pantoprazole was significantly decreased by L-NAME. The inhibitory effect of L-NAME was antagonized by prior administration of L-arginine. The GMBF and the content of NO^-₂/NO^-₃ in gastric mucosa and serum were increased by the intravenous administration of pantoprazole. This effect was prevented by the pretreatment of L-NAME, but the antisecretion effect of pantoprazole was not affected by L-NAME.

CONCLUSION: Pantoprazole can protect gastric muc-osa against the lesions in rats by the mediation of nitric oxide (NO), and the protective effect has no relation with its antisecretory action of gastric acid.

Effects of acupuncturing Tsusanli (ST36) on expression of nitric oxide synthase in hypothalamus and adrenal gland in rats with cold stress ulcer

AIM: To study the protective effect of acupuncturing Tsusanli (S_T36) on cold stress ulcer, and the expression of nitric oxide synthase (NOS) in hypothalamus and adrenal gland.

METHODS: Ulcer index in rats and RT-PCR were used to study the protective effect of acupuncture on cold stress ulcer, and the expression of NOS in hypothalamus and adrenal gland. Images were analyzed with semi-quantitative method.

RESULTS: The ulcer index significantly decreased in rats with stress ulcer. Plasma cortisol concentration was up regulated during cold stress, which could be depressed by pre-acupuncture. The expression of NOS1 in hypothalamus increased after acupuncture. The increased expression of NOS2 was related with stress ulcer, which could be decreased by acupuncture. The expression of NOS3 in hypothalamus was similar to NOS2, but the effect of acupuncture was limited. The expression of NOS2 and NOS3 in adrenal gland increased after cold stress, only the expression of NOS1 could be repressed with acupuncture. There was no NOS2 expression in adrenal gland in rats with stress ulcer.

CONCLUSION: The protective effect of acupuncturing Tsusanli (S_T36) on the expression of NOS in hypothalamus and adrenal gland can be achieved.

Modulation of prostaglandin biosynthesis by nitric oxide and nitric oxide donors

The biosynthesis and release of nitric oxide (NO) and prostaglandins (PGs) share a number of similarities. Two major forms of nitric-oxide synthase (NOS) and cyclooxygenase (COX) enzymes have been identified to date. Under normal circumstances, the constitutive isoforms of these enzymes (constitutive NOS and COX-1) are found in virtually all organs. Their presence accounts for the regulation of several important physiological effects (e.g. antiplatelet activity, vasodilation, and cytoprotection). On the other hand, in inflammatory setting, the inducible isoforms of these enzymes (inducible NOS and COX-2) are detected in a variety of cells, resulting in the production of large amounts of proinflammatory and cytotoxic NO and PGs. The release of NO and PGs by the inducible isoforms of NOS and COX has been associated with the pathological roles of these mediators in disease states as evidenced by the use of selective inhibitors. An important link between the NOS and COX pathways was made in 1993 by Salvemini and coworkers when they demonstrated that the enhanced release of PGs, which follows inflammatory mechanisms, was nearly entirely driven by NO. Such studies raised the possibility that COX enzymes represent important endogenous "receptor" targets for modulating the multifaceted roles of NO. Since then, numerous papers have been published extending the observation across various cellular systems and animal models of disease. Furthermore, other studies have highlighted the importance of such interaction in physiology as well as in the mechanism of action of drugs such as organic nitrates. More importantly, mechanistic studies of how NO switches on/off the PG/COX pathway have been undertaken and additional pathways through which NO modulates prostaglandin production unraveled. On the other hand, NO donors conjugated with COX inhibitors have recently found new interest in the understanding of NO/COX reciprocal interaction and potential clinical use. The purpose of this article is to cover the advances which have occurred over the years, and in particular, to summarize experimental data that outline how the discovery that NO modulates prostaglandin production has impacted and extended our understanding of these two systems in physiopathological events.

Effect of nNOS/iNOS expression on cell apoptosis during stress ulcer of gastric mucosa in mice

AIM: To determine the effect of different type of NOS expression on gastric mucosal cell apoptosis during stress ulcer in mice.

METHODS: Apoptotic cells were quantitated in gastric mucosa by terminal deoxynucleatidyl transferase mediated dUTP nick and labelling (TUNEL) techniques. The expression of nNOS/iNOS proteins was detected by immunohistochemical method. The effects of different dose of nitric oxide inhibitor NG-nitro-L-arginine methyl ester (L-NAME) on gastric mucosal apoptosis was investigated in immersion-restraint stress model of mice.

RESULTS: The expression of iNOS was highly correlated with the apoptotic cell quantities of gastric mucosa. In contract to the high dose of L-NAME (20.0 mg/kg) that increased the quantity of apoptosis 25.8% (P <0.05), small dose of L-NAME (2.0 mg/kg) decreased the quantity of apoptosis 34.6% (P <0.01).

CONCLUSION: The expression of NO is a double-edged sword, a low amount of NO produced by neuronal forms of NOS performs many physiological functions. On the contrary, higher concentration of NO produced by inducible form of NOS induces the epithelial cell apoptosis under stress condition.