Role of L-arginine in ibuprofen-induced oxidative stress and neutrophil infiltration in gastric mucosa

Pharmacological insight of rutin as a potential candidate against peptic ulcer

Peptic ulcer is a sore on the stomach lining that results from the erosion of the gastrointestinal tract mucosa due to various influencing factors. Of these, Helicobacter pylori infection and non-steroidal anti-inflammatory drugs (NSAIDs) stand out as the most prominent causes. This condition poses a significant global health concern due to its widespread impact on individuals worldwide. While various treatment strategies have been employed, including proton pump inhibitors and histamine-2 receptor antagonists, these have notable side effects and limitations. Thus, there is a pressing need for new treatments to address this global health issue. Rutin, a natural flavonoid, exhibits a range of biological activities, including anti-inflammatory, anticancer, and antioxidant properties. This review explores the potential anti-ulcer effect of rutin in experimental models and how rutin can be a better alternative for treating peptic ulcers. We used published literature from different online databases such as PubMed, Google Scholar, and Scopus. This work highlights the abundance of rutin in various natural sources and its potential as a promising option for peptic ulcer treatment. Notably, the anti-inflammatory properties of rutin, which involve inhibiting inflammatory mediators and the COX-2 enzyme, are emphasized. While acknowledging the potential of rutin, it is important to underscore the necessity for further research to fully delineate its therapeutic potential and clinical applicability in managing peptic ulcers and ultimately improving patient outcomes. This review on the anti-ulcer potential of rutin opened a new door for further study in the field of alternative medicine in peptic ulcer management.

Gastro-protective effect of l-arginine against nitric oxide deficiency-related mucosal injury induced by indomethacin: Does age matter?

Gastric ulcer is a common disease with increased prevalence in the aged population. Aged gastric mucosa has increased susceptibility to injury along with nonsteroidal anti-inflammatory drugs use due to impaired mucosal defense and decreased vasodilator release. We investigated whether l-arginine could protect against age-related gastric ulceration induced by indomethacin. Aged and adult male Wistar rats were administered sole and combined treatment of  l-arginine and Nω -nitro-l-arginine methyl ester ( l-NAME) before induction of gastric ulceration by indomethacin. The gastroprotective effect of  l-arginine was displayed only in adult rats with indomethacin-induced gastric ulceration, as evidenced by a significant decrease in ulcer index, oxidative stress parameters, and mucosal myeloperoxidase activity along with increased mucosal PGE2 levels. Interestingly, the mucosal gene expressions of NF-кB, iNOS, and COX-2 were significantly suppressed by  l-arginine pretreatment and aggregated upon pretreatment with  l-NAME in both adult and aged rats treated with indomethacin. In conclusion,  l-arginine protected the rats' gastric mucosa against indomethacin-induced gastric ulceration, possibly, at least in part, by enhancement of mucosal nitric oxide/PGE2 content along with suppressing gastric inflammation and oxidative stress. This study supposed that the gastroprotective effect of  l-arginine depends on aging, and even so, the adoption of a new approach to gastric ulcer treatment for the aged population is warranted.

Study on the mechanism of Fufang E'jiao Jiang on precancerous lesions of gastric cancer based on network pharmacology and metabolomics

ETHNOPHARMACOLOGICAL RELEVANCE

Fufang E'jiao Jiang (FEJ) is a prominent traditional Chinese medicine prescription, which consists of Asini Corii Colla (Donkey-hide gelatin prepared by stewing and concentrating from the hide of Equus asinus Linnaeus., ACC), Codonopsis Radix (the dried roots of Codonopsis pilosula (Franch.) Nannf., CR), Ginseng Radix et Rhizoma Rubra (the steamed and dried root of Panax ginseng C.A. Mey., GRR), Crataegi Fructus (the mature fruits of Crataegus pinnatifida Bunge., CF), and Rehmanniae Radix Praeparata (the steamed and sun dried tuber of Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. & C.A. Mey., RRP). It is a popularly used prescription for "nourishing Qi and nourishing blood".

AIM OF THE STUDY

To explore the potential mechanism of FEJ on precancerous lesion of gastric cancer in rats by combining network pharmacology and metabolomics.

METHODS

Traditional Chinese Medicine Systems Pharmacology and Bioinformatics Analysis Tool for Molecular mechanism of Traditional Chinese Medicine were used to identify the ingredients and potential targets of FEJ. GeneCards database was used to define PLGC-associated targets. We built a herb-component-disease-target network and analyzed the protein-protein interaction network. Underlying mechanisms were identified using Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. In addition, 40% ethanol, N-methyl-N'-nitro-N-nitroguanidine and irregular eating were used to establish PLGC rats model. We also evaluated the efficacy of FEJ on MNNG-induced PLGC rats by body weight, histopathology, blood routine and cytokine levels, while the predicted pathway was determined by the Western blot. Ultra-performance liquid chromatography-tandem mass spectrometry-based serum non-targeted metabolomics was used to select potential biomarkers and relevant pathways for FEJ in the treatment of PLGC.

RESULTS

Network pharmacology showed that FEJ exhibited anti-PLGC effects through regulating ALB, TNF, VEGFA, TP53, AKT1 and other targets, and the potential pathways mainly involved cancer-related, TNF, PI3K-AKT, HIF-1, and other signaling pathways. Animal experiments illustrated that FEJ could suppress inflammation, regulate gastrointestinal hormones, and inhibit the expression of PI3K/AKT/HIF-1α pathway-related proteins. Based on serum non-targeted metabolomics analysis, 12 differential metabolites responding to FEJ treatment were identified, and metabolic pathway analysis showed that the role of FEJ was concentrated in 6 metabolic pathways.

CONCLUSION

Based on network pharmacology, animal experiments and metabolomics, we found that FEJ might ameliorate gastric mucosal injury in PLGC rats by regulating gastrointestinal hormones and inhibiting inflammation, and its mechanism of action is related to the inhibition of excessive activation of PI3K/AKT/HIF-1α signaling pathway and regulation of disorders of body energy metabolism. This comprehensive strategy also provided a reasonable way for unveiling the pharmacodynamic mechanisms of multi-components, multi-targets, and multi-pathways in Traditional Chinese Medicine.

Anti-Inflammatory Potentials of the n-Hexane Fraction of Alstonia boonei Stem Bark in Lipopolysaccharide-Induced Inflammation in Wistar Rats

Background

Inflammation is a protective response of the host to infections and tissue damage and medicinal plants have been used to regulate inflammatory response. The phytochemical contents of the n-hexane fraction of Alstonia boonei and their anti-inflammatory potentials in lipopolysaccharide-induced inflammation were investigated in rat liver.

Materials and Methods

A quantity of 5 mg/kg lipopolysaccharide (LPS) was used to induce inflammation in twenty-five male Wistar rats, grouped (n = 5) and treated as follows: negative control (10 mL/kg saline), positive control (1 mg/kg ibuprofen); 50, 100 and 20 mg/kg of the n-hexane fraction of Alstonia boonei were administered to test groups. In another experiment, twenty rats (n = 5, without LPS) were administered the same doses of the n-hexane fraction of A. boonei and ibuprofen for seven days. At the end of the experiment, animals were sacrificed, serum was obtained from blood and liver mitochondria isolated in a refrigerated centrifuge. Mitochondrial permeability transition (mPT) pore opening and mitochondrial F₀F₁ ATPase (mATPase) were determined spectrophotometrically. Serum interleukins 1β, 6 (IL-1β, IL-6), tumour necrosis factor alpha (TNF-α), C-reactive protein (CRP) and creatine kinase (CK), gamma glutamyl transferase (GGT), aspartate and alanine aminotransferases (AST and ALT,) of the animals in which inflammation was induced using LPS but treated with graded doses of n-hexane fraction of A. boonei were determined using the ELISA technique. The phytochemical contents of the n-hexane fraction of A. boonei were determined using ultra performance liquid chromatography-tandem mass spectrometer (UHPLC-MS).

Results

Calcium induced mPT in 8 fold and LPS induced mPT 14 fold in the negative control while the n-hexane fraction reversed mPT in the treated groups (50, 100 and 200 mg/kg) to 2, 4, 4 folds, respectively. LPS treatment of the negative group enhanced F₀F₁ mATPase activity, increased CRP, TNF-α, IL-1β, IL-6 levels as well as CK, AST, ALT and GGT activities. These values were significantly reduced by 100 and 200 mg/kg of the n-hexane fraction. UHPLC-MS analysis of the fraction revealed the presence of terpenoids, phenolics and sphingolipids.

Conclusion

These results showed that bioactive phytochemicals present in the n-hexane fraction of A. boonei were not toxic, have an anti-inflammatory effect and could be used for the treatment of inflammatory diseases.

Gastroprotective effect and mode of action of methanol extract of Sphenodesme involucrata var. paniculata (C.B. Clarke) Munir (Lamiaceae) leaves on experimental gastric ulcer models

Sphenodesme involucrata var. paniculata (C. B. Clarke) Munir, endemic to South Asia, is used by tribal for alleviation from abdominal disorders, inflammation and body pain. However, the gastroprotective properties of this species have not yet been studied. The leaves of S. involucrata were extracted by Soxhlet extraction using different solvents successively and the extracts were analyzed for antioxidant and anti-Helicobacter pylori activities using different in vitro assays. The chemical composition of methanol extract of S. involucrata (MESi) was analysed by gas chromatography-mass spectrometry (GC-MS). The gastroprotective action of the MESi at the doses of 100, 200, and 400 mg/kg were evaluated in absolute ethanol, acidified ethanol (EtOH/HCl) and nonsteroidal anti-inflammatory drug (NSAID) induced rat experimental models. To elucidate the mode of antiulcerogenic action, the antisecretory parameters (gastric juice volume, pH, and total acidity) and the catalase (CAT) and superoxide dismutase (SOD) enzymes activity and malondialdehyde (MDA) level were evaluated in gastric ulcer tissue. Also the stomachs of the animals were subjected to histological assessment. MESi presented a high antioxidant activity in several oxidants in vitro systems (DPPH^•, ABTS^•+ and FRAP) and it demonstrated a good spectrum of inhibitory activity against H. pylori growth (MIC, 100 μg/mL). GC-MS analysis of MESi indicated the presence of twenty one compounds, among them phenol (21.84%), hexadecanoic acid (15.96%), (9E, 12E)-9, 12-octadecadienoyl chloride (11.15%) and palmitic acid-β-monoglyceride (8.80%) were found higher. MESi (100, 200 and 400 mg/kg, p.o.) produced significant reduction (p < 0.01) of lesion area in the ethanol, acidified ethanol and indomethacin-induced ulcer models. In the pylorus ligation induced ulcer model, the treatment with MESi significantly altered the gastric secretion by decreasing total gastric juice volume and gastric acidity as well as by increasing the gastric pH. MESi pre-treatment significantly (p < 0.05) restored the depleted activity of SOD, CAT enzymes and reduced MDA levels in the gastric tissue as well as the histological analysis of the stomachs of the animals showed that the MESi also prevents local action of offensive factors. Collectively, the present study results suggest that the methanol extract of S. involucrata leaves demonstrates gastroprotective action, supporting the folkloric usage of the plant to treat gastro-intestinal disturbances.

Serotonin and histamine mediate gastroprotective effect of fluoxetine against experimentally-induced ulcers in rats

Research in the treatment of gastric ulcer has involved the investigation of new alternatives, such as anti-depressant drugs. The present study was designed to investigate the gastroprotective effects of fluoxetine against indomethacin and alcohol induced gastric ulcers in rats and the potential mechanisms of that effect. Fluoxetine (20 mg/kg) was administered IP for 14 days. For comparative purposes, other rats were treated with ranitidine (30 mg/kg). Thereafter, after 24 h of fasting, INDO (100 mg/kg) or absolute alcohol (5 ml/kg) was administered to all rats (saline was administered to naïve controls) and rats in each group were sacrificed 5 h (for INDO rats) or 1 h (for alcohol rats) later. Macroscopic examination revealed that both fluoxetine and ranitidine decreased ulcer scores in variable ratios, which was supported by microscopic histopathological examination. Biochemical analysis of fluoxetine- or ranitidine-pre-treated host tissues demonstrated reductions in tumor necrosis factor (TNF)-α and myeloperoxidase (MPO) levels and concomitant increases in gastric pH, nitric oxide (NO) and reduced glutathione (GSH) contents. Fluoxetine, more than ranitidine, also resulted in serotonin and histamine levels nearest to control values. Moreover, immuno-histochemical analysis showed that fluoxetine markedly enhanced expression of cyclo-oxygenases COX-1 and COX-2 in both models; in comparison, ranitidine did not affect COX-1 expression in either ulcer model but caused moderate increases in COX-2 expression in INDO-induced hosts and high expression in alcohol-induced hosts. The results here indicated fluoxetine exhibited better gastroprotective effects than ranitidine and this could be due to anti-secretory, anti-oxidant, anti-inflammatory and anti-histaminic effects of the drug, as well as a stabilization of gastric serotonin levels.

Levels of MDA and SOD in acute gastric mucosal injury in rats exposed to positive acceleration

AIM: To determine the levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in acute gastric mucosal injury in rats exposed to positive acceleration (+Gz), observe the impact of +Gz exposure on gastric mucosal injury, and clarify the role of oxygen free radicals in this process.

METHODS: Thirty male SD rats were randomly divided into three groups: A (ethanol), B (ethanol with +5Gz exposure), and C (ethanol with +10Gz exposure). All rats were intragastrically given ethanol (0.4 mL/100 mg) after 24 h of fasting and water deprivation for 12 h. One hour after ethanol administration, group A did not undergo +Gz, while groups B and C were continuously exposed to +5Gz and +10Gz for 3 minutes, respectively. Immediately after +Gz exposure, gastric tissue samples were taken to observe gastric mucosal injury by light microscopy. The indexes of gastric mucosal injury were calculated, and the contents of MDA and SOD in the gastric mucosa were determined by ELISA.

RESULTS: Gastric mucosal injury was observed in all the groups, and gastric mucosal injury was most severe in group C, followed by groups B and A. Group A had mildest gastric mucosal injury. Group B showed visible gastric mucosal congestion, edema and scattered bleeding spots, and light microscopy revealed acute inflammatory cell infiltration. The indexes of gastric mucosal injury were significantly higher in group B than in group A (naked eye: 23.654 ± 9.678 vs 11.410 ± 3.742; light microscopy: 5.000 ± 1.054 vs 3.800 ± 1.399; both P < 0.05). Group C had heaviest gastric mucosal injury. Diffuse gastric mucosal congestion, edema, erosion and many bleeding spots were visible, and light microscopy revealed disorderly arranged gland structure, interstitial congestion, erosion, and acute inflammatory cell infiltration. The indexes of gastric mucosal injury were significantly higher in group C than in groups A and B (naked eye: 49.080 ± 10.254, light microscopy: 9.400 ± 2.011; all P < 0.05). Compared with group A, the content of MDA in the gastric mucosa did not rise significantly in group B (0.255 ± 0.074 vs 0.235 ± 0.044, P > 0.05); however, MDA content in group C (0.376 ± 0.084) was significantly higher than those in groups A and B (both P < 0.05). The content of SOD in the gastric mucosa was significantly lower in group C than in groups A and B (8.852 ± 1.001 vs 10.000 ± 1.067, 10.694 ± 0.965, P < 0.05), although no significant difference was observed between the latter two groups (P > 0.05).

CONCLUSION: +Gz exposure aggravates acute gastric mucosal injury in rats possibly by altering the contents of MDA and SOD in gastric tissue.

The influence of short-term L-arginine supplementation on rats' muscular and hepatic cells in ischemia-reperfusion syndrome

Due to the complex mechanisms of L-arginine activity, it is difficult to determine the clinical significance of supplementation with this amino acid. The objective of this study was to determine the influence of short-term supplementation with L-arginine in stress conditions, induced by ischemia-reperfusion syndrome, by assessing the damage to muscular and hepatic cells on the basis of creatine kinase (CK), alanine aminotransferase (ALAT) and aspartic aminotransferase (AspAT) activity in blood and the level of oxygen free radicals in analyzed tissues of rats. We observed that induced ischemia of hind limb caused an increase in CK, ALAT and AspAT activity and an increase in the level of free radicals in liver, but not in skeletal muscle. Supplementation with L-arginine led to a reduction in serum activity of CK and AspAT and reduction of the level of free radicals in analysed tissues. Simultaneous supplementation with L -arginine AND L-NAME resulted in a reversal of changes induced by L-arginine supplementation in the case of AspAT and free radicals in skeletal muscle. The results indicate that under conditions of ischemia-reperfusion, short-term administration of L-arginine has a protective effect on skeletal muscle manifesting itself by reduction of CK in the serum and reduction of free radicals level in THIS tissue.

Oxidative stress, nitric oxide and prostaglandin E2 levels in the gastrointestinal tract of aging rats

Objectives

To evaluate the presence of oxidative stress and alterations in the levels of two cytoprotective agents, prostaglandin E2 and nitric oxide, in the gastrointestinal tract of aging rats.

Methods

The production of superoxide anion, lipid peroxides, levels of superoxide dismutase and catalase, and production of prostaglandin E2 and nitric oxide in the stomach and duodenum of rats were determined at 1.5, 3, 12, 18 and 24 months of age.

Key findings

Oxidative stress was present in the stomach of the old rats (24 months), whereas prostaglandin E2 and nitric oxide production remained stable at 18 and 24 months. In the duodenum, no oxidative stress was observed at 24 months, but at 18 months, an increase in superoxide anion levels was detected. Prostaglandin E2 remained constant in the aged rats but nitric oxide decreased significantly at 24 months.

Conclusions

The absence of macroscopic gastric injury throughout the gastrointestinal tract indicates that the oxidative stress in the stomach and the significant decrease of nitric oxide in the duodenum in the old rats are not sufficient to disrupt the mucosal defence network. The results support the notion that the disruption of the mucosal network is essentially regulated by the cytoprotective agents prostaglandin E2 and nitric oxide, and that injury appears only when both substances are concurrently reduced.

Effect of Lonicerae Flos extracts on reflux esophagitis with antioxidant activity

AIM: To observe the effects of traditional antiinflammatory medicine Lonicerae Flos (LF) on rat reflux esophagitis (RE) induced by pylorus and forestomach ligation compared with the well-known proton antioxidant, α-tocopherol.

METHODS: Rats were pretreated with three different dosages of LF (500, 250 and 125 mg/kg) orally, once a day for 14 d before pylorus and forestomach ligation. Nine hours after pylorus and forestomach ligation, changes to the stomach and esophagus lesion areas, gastric volumes, acid and pepsin outputs, antioxidant effects, esophageal lipid peroxidation, superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), myeloperoxidase and glutathione (GSH) levels, and collagen contents (marker of flexibility) were observed on the esophageal and fundic histopathology. The results were compared with an α-tocopherol (once orally, 1 h before operation, 30 mg/kg) treated group in which the effects on RE were already confirmed.

RESULTS: Pylorus and forestomach ligations caused marked increases of gross esophageal and gastric mucosa lesion areas, which corresponded with histopathological changes. In addition, increases of esophageal lipid peroxidation, decreases of SOD, CAT, and GSH-free radical scavengers, increases of collagen were observed. However, these pylorus and forestomach ligation induced RE were dose-dependently inhibited by treatment of 500, 250 and 125 mg/kg of LF extract, mediated by antioxidant effects. RE at 250 mg/kg showed similar effects α-tocopherol.

CONCLUSION: The results suggest that antioxidant effects of LF could attenuate the severity of RE and prevent the esophageal mucosal damage, and validate its therapeutic use in esophageal reflux disease.

Role of coxibs in the strategies for gastrointestinal protection in patients requiring chronic non-steroidal anti-inflammatory therapy

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most commonly prescribed drugs due to their high efficacy in the treatment of pain, fever, inflammation and rheumatic disorders. However, their use is associated with the occurrence of adverse effects at the level of digestive tract, ranging from dyspeptic symptoms, gastrointestinal erosions and peptic ulcers to more serious complications, such as overt bleeding or perforation. To overcome problems related to NSAID-induced digestive toxicity, different therapeutic strategies can presently be considered, including the co-administration of drugs endowed with protective activity on the upper gastrointestinal tract, such as the proton pump inhibitors, or the prescription of coxibs, which have been clinically developed as anti-inflammatory/analgesic drugs characterized by reduced damaging activity on gastrointestinal mucosa. The availability of different treatment options, to reduce the risk of NSAID-induced adverse digestive effects, has fostered intensive preclinical and clinical research aimed at addressing a number of unresolved issues and to establish rational criteria for an appropriate use of coxibs in the medical practice. Particular attention is being paid to the management of patients with high degrees of digestive risk, resulting by concomitant treatment with low-dose aspirin for anti-thrombotic prophylaxis or ongoing symptomatic gastroduodenal ulcers. The present review discusses the most relevant lines of evidence concerning the position of coxibs in the therapeutic strategies for gastrointestinal protection in patients who require NSAID therapy and hold different levels of risk of developing adverse effects at the level of digestive tract.

Clinical efficacy of esomeprazole in the prevention and healing of gastrointestinal toxicity associated with NSAIDs in elderly patients

NSAIDs are widely prescribed for the treatment of pain, inflammation and rheumatic disorders, but their use is associated with adverse gastrointestinal effects, ranging from dyspeptic symptoms and peptic ulcers to more serious complications. Elderly patients are at high risk of experiencing NSAID-induced gastrointestinal tract injury and should be considered candidates for prophylactic pharmacological therapy. In studies conducted in adult patients, proton pump inhibitors (PPIs) such as esomeprazole have been shown to prevent or reduce NSAID-induced gastrointestinal injury. The beneficial effects of esomeprazole can be ascribed largely to its ability to maintain sustained inhibition of gastric acid secretion, although there is evidence to suggest that pharmacodynamic properties unrelated to acid inhibition may also contribute to the gastroprotective effects of this agent. Although there are limited data on the use of esomeprazole specifically in elderly patient populations, studies of patients at high risk of NSAID-induced gastrointestinal toxicity because of advanced age indicate that this PPI is both effective and well tolerated when administered in conjunction with NSAIDs. Thus, esomeprazole can be regarded as a useful option for prophylactic therapy in elderly patients receiving long-term NSAID therapy.

Inhibition of proinflammatory tumor necrosis factor-{alpha}-induced inducible nitric-oxide synthase by xanthine-based 7-[2-[4-(2-chlorobenzene)piperazinyl]ethyl]-1,3-dimethylxanthine (KMUP-1) and 7-[2-[4-(4-nitrobenzene)piperazinyl]ethyl]-1, 3-dimethylxanthine (KMUP-3) in rat trachea: The involvement of soluble guanylate cyclase and protein kinase G

In the study of anti-proinflammation by 7-[2-[4-(2-chlorobenzene)piperazinyl] ethyl]-1,3-dimethylxanthine (KMUP-1) and 7-[2-[4-(4-nitrobenzene)piperazinyl]ethyl]-1,3-dimethylxanthine (KMUP-3), exposure of rat tracheal smooth muscle cells (TSMCs) to tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, increased the expression of inducible nitric-oxide synthase (iNOS) and NO production and decreased the expression of soluble guanylate cyclase alpha1 (sGCalpha1), soluble guanylate cyclase beta1 (sGCbeta1), protein kinase G (PKG), and the release of cGMP in TSMCs. The cell-permeable cGMP analog 8-Br-cGMP, xanthine-based KMUP-1 and KMUP-3, and the phosphodiesterase 5 inhibitor zaprinast all inhibited TNF-alpha-induced increases of iNOS expression and NO levels and reversed TNF-alpha-induced decreases of sGCalpha1, sGCbeta1, and PKG expression. These results imply that cGMP enhancers could have anti-proinflammatory potential in TSMCs. TNF-alpha also increased protein kinase A (PKA) expression and cAMP levels, cyclooxygenase-2 (COX-2) expression, and activated productions of prostaglandin (PG) E2 and 6-keto-PGF1alpha (stable PGI2 metabolite). Dexamethasone and N-[2-(cyclohexyloxyl)-4-nitrophenyl]-methane sulfonamide (NS-398; a selective COX-2 inhibitor) attenuated TNF-alpha-induced expression of COX-2 and activated productions PGE2 and PGI2. However, KMUP-1 and KMUP-3 did not affect COX-2 activities and did not further enhance cAMP levels in the presence of TNF-alpha. It is suggested that TNF-alpha-induced increases of PKA expression and cAMP levels are mediated by releasing PGE2 and PGI2, the activation products of COX-2. In conclusion, xanthine-based KMUP-1 and KMUP-3 inhibit TNF-alpha-induced expression of iNOS in TSMCs, involving the sGC/cGMP/PKG expression pathway but without the involvement of COX-2.

Role of the nrf-2 gene in protection and repair of gastric mucosa against oxidative stress

Helicobacter pylori infection, as well as NSAIDs induce oxidative stress on gastric mucosa, thereby causing mucosal damage and retarding mucosal repair. Cells can survive against chronic oxidative stress by enhancing activities of anti-oxidant enzymes, thereby protecting cells from DNA damage. Recent studies have clearly shown that the gene encoding Nrf-2 (NF-E2 p45-related factor-2) plays an important role in the induction of antioxidant enzymes against oxidative stress. In this paper, we will describe the cellular mechanisms by which the nrf-2 gene stimulates anti-oxidant enzyme activities during exposure to oxidative stress. Secondly, we will also mention the beneficial effects of sulforaphane, an isothiocyanate family which is abundantly included in broccoli sprouts, on gastric mucosa. Sulforaphane stimulates nrf-2 gene-dependent anti-oxidant enzyme activities, thereby protecting cells from oxidative injury. Finally, we will state our perspective on the efficacy of sulforaphane in protection and repair of gastric mucosa against oxidative stress during H. pylori infection.

Angiogenesis, cell proliferation and apoptosis in gastric ulcer healing. Effect of a selective cox-2 inhibitor

To elucidate the role of cyclooxygenase-2, we compared the effects of rofecoxib, a selective cyclooxygenase-2 inhibitor, and ibuprofen, a nonselective cyclooxygenase inhibitor, on the evolution of acetic-acid-induced gastric ulcers in rats, evaluating growth factor expression, the angiogenic process, cell proliferation and cell apoptosis. Levels of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF), angiogenesis and cell proliferation were analysed by immunohistochemical methods, and apoptosis was evaluated by an enzyme immunoassay. Both growth factors and microvessels appeared to be abundant in the granulation tissue of the ulcer bed. Rofecoxib (2.5 mg/kg/day) and ibuprofen (100 mg/kg/day) delayed ulcer healing, but only rofecoxib treatment provoked a reduction of bFGF expression and inhibition of the development of new microvessels. No changes in VEGF expression were detected. Results also showed that proliferation and apoptosis were increased in control ulcerated animals. Rofecoxib reduced significantly both processes. These findings demonstrate that a reduction of bFGF expression and an antiangiogenic action, as well as proliferation/apoptosis inhibition, are some of the mechanisms possibly implicated in the delay in ulcer healing seen after the administration of the highly selective COX-2 inhibitor rofecoxib.