Adaptive cytoprotection through modulation of nitric oxide in ethanol-evoked gastritis

Lactoferrin mitigates ethanol-induced gastric ulcer via modulation of ROS/ICAM-1/Nrf2 signaling pathway in Wistar rats

Objectives

We aimed to investigate the gastroprotective effect of lactoferrin (LF; 100 & 300 mg/kg) in male Wistar rats versus gastric ulcers induced by 96% ethanol.

Materials and Methods

Rats were randomly allocated into 4 groups: control, ethanol, ethanol+LF100, and ethanol+LF300. LF100 & 300 were given 15 days before ulcer induction. At the end of the experiment, the gastric mucosa was examined macroscopically and microscopically.

Results

The ethanol group showed damage and degeneration of the stomach mucosa in addition to elevation of oxidative and inflammatory biomarkers. LF showed explicit healing of the gastric mucosal damage. LF reduced gastric malondialdehyde (MDA), tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), myeloperoxidase (MPO), and intracellular adhesion molecule-1 (ICAM-1). On the other hand, LF elevated the depleted reduced glutathione (GSH) and Nuclear factor-erythroid factor 2 (Nrf2).

Conclusion

Our current study is the first to study the antiulcer effect of LF via its potential modulatory effects on the ROS/ICAM-1/Nrf2 signaling pathway. Moreover, we concluded that pretreatment with LF100 & 300 mitigated the ethanol-induced gastric ulcer via modulation of both oxidative stress and inflammatory responses.

Agarwood Alcohol Extract Protects against Gastric Ulcer by Inhibiting Oxidation and Inflammation

Background

Agarwood has been used for centuries, especially for treatment of gastrointestinal diseases. Earlier studies of our laboratory suggested that agarwood alcohol extracts (AAEs) provided gastric mucosal protection. This study aims to investigate the ameliorative effect of AAEs on ethanol-induced gastric ulcers and its mechanism.

Methods

Mice were given agarwood induced by the whole-tree agarwood-inducing technique alcohol extract (WTAAE, 0.71, 1.42, and 2.84 g/kg), wild agarwood induced by axe wounds alcohol extract (WAAE, 2.84 g/kg), and burning-chisel-drilling agarwood alcohol extract (FBAAE, 2.84 g/kg) orally, respectively. After 7 days' pretreatment with AAEs, the gastric ulcers were induced by absolute ethanol. The ulcer index, gastric histopathology, biochemical parameters, and inflammatory proteins were evaluated.

Results

Pharmacological results showed AAEs (1.42 and 2.84 g/kg) reduced the gastric occurrence and ulcer inhibition rates up to more than 60%. AAEs decreased the level of nitric oxide (NO) and increased glutathione (GSH) and superoxide dismutase (SOD) levels. Besides, AAEs decreased the levels of interleukin-1β (IL-1β) and interleukin-6 (IL-6), but the interleukin-10 (IL-10) was upregulated. The expressions of nuclear factor kappa B (NF-κB) and phosphorylated protein 38 (p-P38) were inhibited. The effect of WTAAE was better than that of FBAAE and similar to that of WAAE at the dose of 2.84 g/kg.

Conclusions

These results demonstrate that agarwood alleviates the occurrence and development of gastric ulcers via inhibiting oxidation and inflammation.

Gastroprotective effect of Lycium barbarum polysaccharides and C-phycocyanin in rats with ethanol-induced gastric ulcer

This study investigated the gastroprotective effect of Lycium barbarum polysaccharides (LBP) and C-phycocyanin (C-PC) in rats with ethanol-induced gastric ulcer. Rats were divided into 5 groups: normal, ulcer, ulcer treated with 100 mg/kg bw LBP, ulcer treated with 50 mg/kg bw C-PC, and ulcer treated with 50 mg/kg bw LBP and 25 mg/kg bw C-PC. Pretreatment with LBP and/or C-PC was given a week before ulcer induction. Ulcer induction was produced by 50% ethanol administration orally every other day for 4 weeks. After 5-week treatment, the histopathological observation showed that LBP or C-PC attenuated the severity of gastric mucosal damage. LBP decreased serum malondialdehyde (MDA) levels and gastric interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1) levels, and myeloperoxidase (MPO) activity. C-PC decreased serum MDA levels and gastric tumor necrosis factor-α (TNF-α), IL-1β, IL-6, ICAM-1 levels, and MPO activity. Combined LBP and C-PC decreased serum MDA levels and gastric TNF-α, IL-1β, IL-6, and ICAM-1 levels. LBP and/or C-PC increased gastric heat shock protein 70 and non-protein sulfhydryl compounds. Rats with ulcer and treatment had enriched with the family Bacillaceae. Therefore, pretreatment with LBP and/or C-PC attenuated ethanol-induced gastric ulcer in rats via suppressing oxidation and inflammation and increasing gastroprotection.

Gastro-protective, therapeutic and anti-inflammatory activities of Pistacia lentiscus L. fatty oil against ethanol-induced gastric ulcers in rats

Pistacia lentiscus L. (Anacardiaceae) (PL) is a flowering plant that grows in the Mediterranean area. It is traditionally used in the treatment of various skin, respiratory and gastrointestinal disorders AIM OF THE STUDY: In the present study, we investigated the anti-ulcerogenic activity of Pistacia lentiscus fatty oil (PLFO) on ethanol-induced gastric ulcers in Wistar rats MATERIAL AND METHODS: PLFO was orally administered to two experimental groups of rats before or after ethanol induction of gastric ulcer. The lesions of the gastric mucosa were evaluated by macroscopic and histopathological examination. In addition, the amount of nitric oxide (NO) and pro-inflammatory cytokines [tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6)] in the supernatant from cultures of gastric mucosa explants were assessed. Finally, the mucus production and iNOS (inducible NO synthase) expression were determined by histochemical and immunohistochemical analysis, respectively RESULT: Our results indicated that the PLFO pretreatment or PLFO treatment significantly reduced ulcerated and hemorrhagic areas. Additionally, pretreatment or treatment with PLFO after ethanol-induced ulceration significantly reduced the plasma concentration of NO. Furthermore, a significant decrease of NO, IL-6 and TNF-α levels was observed in explant culture supernatants. iNOS expression was also reduced in the gastric mucosa. In contrast, mucus production by goblet cells was enhanced. Interestingly, histological analysis of the gastric mucosa has indicated that PLFO- pretreated and treated groups displayed normal histology CONCLUSION: Our results demonstrate that PLFO display significant prophylactic and therapeutic effects against gastric ulcers. Importantly, the mechanism underlying PLFO activities might implicate inhibition of inflammatory responses during gastric ulcer.

Anti-ulcer and anti-Helicobacter pylori potentials of the ethyl acetate fraction of Physalis alkekengi L. var. franchetii (Solanaceae) in rodent

ETHNOPHARMACOLOGICAL RELEVANCE

Physalis alkekengi L. var. franchetii (Solanaceae) has been widely used in Chinese folk medicine due to its wide distribution throughout the country, for the treatment of a wide range of diseases including heat and cold, sore throat, fever, fungal infection, inflammation, toothache, rheumatism, burn, analgesic, ulcer and urinary diseases. However, the effect of P. alkekengi var. franchetii on ulcer and Helicobacter pylori infection has not been reported to date.

AIM OF THE STUDY

This study was designed to investigate the anti-inflammatory, anti-ulcer, anti-Helicobacter pylori and analgesic properties of ethyl acetate fraction of the crude aqueous methanolic extract from the aerial parts of the plant P. alkekengi L. var. franchetii in rodents.

MATERIALS AND METHODS

Acute toxicity of the crude extract of P. alkekengi L. var. franchetii (PAF) was evaluated in rats. The petroleum ether fraction (PEF), butanol fraction (BF), ethyl acetate fraction (EAF) and aqueous fraction (AF) of crude aqueous methanolic extract from PAF were screened for anti-inflammatory and anti-ulcer potential at doses of 100, 250 and 500mg/kg (p.o.), using carrageenin-induced hind paw edema and ethanol-induced gastric lesions test in rats. In vitro anti-Helicobacter pylori activity of EAF was assayed subsequently. In addition, three doses of EAF were evaluated for analgesic activity using hot plate and writhing tests, respectively. Finally, we performed a phytochemical analysis of EAF.

RESULTS

Four fractions of crude extract from PAF significantly reduced the paw volume in carrageenin-induced hind paw edema model at different doses (100, 250 and 500mg/kg, p.o.). The fraction EAF at a dose of 500mg/kg exhibited the highest (75.92%) (0.150 ± 0.045***, ***p < 0.001) anti-inflammatory potential, which is similar to indomethacin (***P < 0.001)（0.120 ± 0.014***, 80.74% inhibition of inflammation） at 5mg/kg. Pretreatment with EAF (500mg/kg, p.o.) significantly reduced the intensity of gastric mucosal damage and showed higher gastroprotective activity (90.6%) when compared to the standard drug famotidine (84.6%). In addition, EAF fraction also showed a moderate (P < 0.05) anti-Helicobacter pylori activity with a minimal inhibition concentration (MIC) of 500μg/ml. Furthermore, pain sensation was effectively inhibited at 500mg/kg, p.o. of EAF as manifested by an increase (p < 0.001) of latency time in hot plate from 30 to 90min and a decrease (p < 0.001) in count of writhing induced by acetic acid. By HPLC, we determined some steroid, terpenoid and flavonoids (four compounds): kaempferol, quercetin, Blumenol A and physalindicanols A, which were isolated from the ethyl acetate fraction and identified using ¹H NMR and ¹³C NMR spectra analysis.

CONCLUSION

This study demonstrated the anti-inflammatory, anti-ulcer, anti-Helicobacter pylori and analgesic properties of EAF of the crude extract from PAF thus justifying its traditional usage.

Influence of the uronic acid composition on the gastroprotective activity of alginates from three different genus of Tunisian brown algae

Alginates from three genus of Tunisian brown algae were isolated and characterized by size exclusion chromatography and Solid-state NMR spectroscopy. Alginate from Padina pavonica (APP) had the highest molecular weight (Mw) with 147,000g/mol while it was 85,000g/mol for alginate from Cystoseira compressa (ACC) and 58,000g/mol for alginate from Dictyopteris membranaceae (ADM). The mannuronate (M) to guluronate (G) ratios were estimated from spectral deconvolution of the 13C CP/MAS spectra and the results has shown that all the extracts are mannuronic acid-rich alginates with M/G ratio increased in the order ADM - ACC - APP. An interesting gastroprotective effect was observed for the extracts; ADM and ACC exhibited the highest inhibition of gastric lesions, at 50mg/kg, with 83.41% and 75.39% respectively. Otherwise, it has been shown that the gastroprotective effect of alginates depends mainly on their uronic acid composition.

Gastroprotective effects of the isopropanol extract of Artemisia princeps and its gastroretentive floating tablets on gastric mucosal injury

In this study, we investigated the gastroprotective effect of an isopropanol extract from the aerial parts of Artemisia princeps (IPAP) and developed a gastroretentive floating tablet of IPAP (IPAP-FR) for maximized local gastroprotective effects. Pre-treatment with IPAP ameliorated the gastric mucosal hemorrhagic lesions in ethanol/HCl- or indomethacin- treated rats. IPAP decreased mucosal hemorrhage of gastric ulcers induced by ethanol or indomethacin plus pyloric ligation in rats. The optimized floating tablet, IPAP-FR, floated on medium surface with more sustained eupatilin release compared to the non-floating control tablet. X-ray photographs in beagle dogs showed that IPAPFR was retained for > 2 h in the stomach. In the ethanol-induced gastric ulcer rat model, the gastric hemorrhagic lesion was improved more substantially with IPAP-FR compared to the non-floating control tablet. Based on these data, our data suggest that IPAP-FR has an improved therapeutic potential for the treatment of gastric ulcer.

The gastroprotective effect of nobiletin against ethanol-induced acute gastric lesions in mice: impact on oxidative stress and inflammation

CONTEXT

Gastric ulcer is a common gastrointestinal disorder with increasing incidence and prevalence attributed to loss of balance between aggressive and protective factors. Nobiletin (NOB), a major component of polymethoxyflavones in citrus fruits, has a broad spectrum of health beneficial properties including anti-inflammatory and anti-tumor activities. Although NOB was originally shown to possess anti-inflammatory activity, its effects on gastric ulcer were rarely explored previously.

OBJECTIVE

The aim of the present study was to investigate the anti-ulcerogenic activity of NOB on ethanol-induced gastric ulcer in mice and to elucidate the underlying mechanisms.

METHODS

Seventy-two male Kunming mice administered with absolute ethanol (0.2 ml/animal) were pretreated with NOB (5, 10 or 20 mg/kg), cimetidine (100 mg/kg), or vehicles by intragastric administration in different experimental groups for three days, and animals were euthanized 3 h after ethanol ingestion. Gross and microscopic lesions, immunological and biochemical parameters were taken into consideration.

RESULTS

The results showed that ethanol induced gastric injury, increased malondialdehyde (MDA) levels, decreased glutathione (GSH) content, superoxide dismutase (SOD) activity, and prostaglandin E₂ (PGE₂) levels, increased pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) levels and myeloperoxidase (MPO) activity, as well as the expression MAPK signaling pathway. Pretreatment with NOB significantly attenuated the gastric lesions as compared to the ethanol group.

CONCLUSIONS

These findings suggest that the gastroprotective activity is attribute to the improvement of antioxidant activities, the stimulation of PGE₂, and the reduction of pro-inflammatory cytokines through the MAPK pathway.

Protective effects of alginate-chitosan microspheres loaded with alkaloids from Coptis chinensis Franch. and Evodia rutaecarpa (Juss.) Benth. (Zuojin Pill) against ethanol-induced acute gastric mucosal injury in rats

Zuojin Pill (ZJP), a traditional Chinese medicine formula, consists of Coptis chinensis Franch. and Evodia rutaecarpa (Juss.) Benth. in a ratio of 6:1 (w/w) and was first recorded in “Danxi’s experiential therapy” for treating gastrointestinal disorders in the 15th century. However, the poor solubility of alkaloids from ZJP restricted the protective effect in treating gastritis and gastric ulcer. The aim of the study was to investigate the protective mechanism of mucoadhesive microspheres loaded with alkaloids from C. chinensis Franch. and E. rutaecarpa (Juss.) Benth. on ethanol-induced acute gastric mucosal injury in rats. Surface morphology, particle size, drug loading, encapsulation efficiency, in vitro drug release, mucoadhesiveness, and fluorescent imaging of the microspheres in gastrointestinal tract were studied. The results showed that the mucoadhesive microspheres loaded with alkaloids could sustain the release of drugs beyond 12 hours and had gastric mucoadhesive property with 82.63% retention rate in vitro. The fluorescence tracer indicated high retention of mucoadhesive microspheres within 12 hours in vivo. The mucoadhesive microspheres loaded with alkaloids could reduce the gastric injury by decreasing the mucosal lesion index, increasing the percentage of inhibition and increasing the amount of mucus in the gastric mucosa in an ethanol-induced gastric mucosal injury rat model. Moreover, the mucoadhesive microspheres loaded with alkaloids reduce the inflammatory response by decreasing the levels of tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), downregulating the mRNA expression of inducible nitric oxide synthase, TNF-α, and IL-1β in gastric mucosa. All the results indicate that mucoadhesive microspheres loaded with alkaloids could not only increase the residence time of alkaloids in rat stomach, but also exert gastroprotective effects through reducing the inflammatory response on ethanol-induced gastric mucosal damage. Thus, these microspheres could be developed as a potential controlled release drug for treatment of gastric ulcer.

Protective effects of pogostone from Pogostemonis Herba against ethanol-induced gastric ulcer in rats

We examined the protective effect of pogostone (PO), a chemical constituent isolated from Pogostemonis Herba, on the ethanol-induced gastric ulcer in rats. Administration of PO at doses of 10, 20 and 40 mg/kg body weight prior to ethanol ingestion effectively protected the stomach from ulceration. The gastric lesions were significantly ameliorated by all doses of PO as compared to the vehicle group. Pre-treatment with PO prevented the oxidative damage and the decrease of prostaglandin E2 (PGE2) content. In addition, PO pretreatment markedly increased the mucosa levels of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT), and decreased gastric malonaldehyde (MDA), relative to the vehicle group. In the mechanistic study, significant elevation of non-protein-sulfhydryl (NP-SH) was observed in the gastric mucosa pretreated by PO. Analysis of serum cytokines indicated that PO pretreatment obviously elevated the decrease of interleukin-10 (IL-10) level, while markedly mitigated the increment of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) secretions in ethanol-induced rats. Taken together, these results strongly indicate that PO could exert a gastro-protective effect against gastric ulceration, and the underlying mechanism might be associated with the stimulation of PGE2, improvement of antioxidant and anti-inflammatory status, as well as preservation of NP-SH.

Mucoadhesive microparticles for gastroretentive delivery: preparation, biodistribution and targeting evaluation

The aim of this research was to prepare and characterize alginate-chitosan mucoadhesive microparticles containing puerarin. The microparticles were prepared by an emulsification-internal gelatin method using a combination of chitosan and Ca²⁺ as cationic components and alginate as anions. Surface morphology, particle size, drug loading, encapsulation efficiency and swelling ratio, in vitro drug released, in vitro evaluation of mucoadhesiveness and Fluorescence imaging of the gastrointestinal tract were determined. After optimization of the formulation, the encapsulation efficiency was dramatically increased from 70.3% to 99.2%, and a highly swelling ratio was achieved with a change in particle size from 50.3 ± 11.2 μm to 124.7 ± 25.6 μm. In ethanol induced gastric ulcers, administration of puerarin mucoadhesive microparticles at doses of 150 mg/kg, 300 mg/kg, 450 mg/kg and 600 mg/kg body weight prior to ethanol ingestion significantly protected the stomach ulceration. Consequently, significant changes were observed in inflammatory cytokines, such as prostaglandin E₂ (PGE₂), tumor necrosis factor (TNF-α), interleukin 6 (IL-6), and interleukin1β (IL-1β), in stomach tissues compared with the ethanol control group. In conclusion, core-shell type pH-sensitive mucoadhesive microparticles loaded with puerarin could enhance puerarin bioavailability and have the potential to alleviate ethanol-mediated gastric ulcers.

Protective effect of ethyl acetate fraction of Acacia ferruginea DC. against ethanol-induced gastric ulcer in rats

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional systems of medicine, stem bark of Acacia ferruginea DC. is used for the treatment of itching, leucoderma, ulcers, stomatitis and diseases of the blood. In the present study, we determined antioxidant and anti-ulcerogenic activities of Acacia ferruginea stem bark.

MATERIALS AND METHODS

Acetone extract and its sub-fractions of Acacia ferruginea stem bark were subjected to assess their antioxidant potential using various in vitro systems such as DPPH(•), ABTS(•+) scavenging, FRAP and phosphomolybdenum reduction activities. Based on the antioxidant potential, the ethyl acetate fraction was used to evaluate the protective effect of ethanol-induced gastric damage in rat model. Enzyme activities such as superoxide dismutase, glutathione, catalase and lipid peroxidation were also determined in the stomach tissues.

RESULTS

Ethyl acetate fraction (AFE) of Acacia ferruginea stem bark registered higher antioxidant and free radical scavenging activities than the crude acetone extract and other fractions. In addition, AFE exhibited that the IC50 values of DPPH (2.5µg/ml) and ABTS (1.8µg/ml) were lower when compared to the standard quercetin (12.4µg/ml and 4.7µg/ml, respectively). In ethanol induced gastric ulcer, administration of AFE at doses of 10mg/kg, 50mg/kg and 100mg/kg body weight prior to ethanol ingestion significantly protected the stomach ulceration. Consequently significant changes were observed in enzyme activities such as SOD, CAT, GSH and LPO in the stomach tissues when compared with ethanol control group.

CONCLUSION

It is concluded that the ethyl acetate fraction of Acacia ferruginea stem bark possessed higher antioxidant and anti-ulcerogenic activities. Based on the results, we suggest that Acacia ferruginea stem bark has potential to provide a therapeutic approach to ethanol mediated ulcer as an effective anti-ulcer agent.

Increased oxidative stress may lead to impaired adaptive cytoprotection in the gastric mucosa of portal hypertensive rat

BACKGROUND AND AIMS

In the gastric mucosa of portal hypertensive rats, adaptive cytoprotection against ethanol-induced damage is impaired. The aim of this study was to determine relation between impaired adaptive cytoprotection and oxidative stress.

METHODS

Portal hypertension was produced in male Sprague-Dawley rats by inducing staged portal vein occlusion. Oxidative stress levels were evaluated by measuring malondialdehyde and nitrotyrosine levels in the rat gastric mucosa with or without 10% ethanol pretreatment. Inhibition of oxidative stress by an anti-oxidant agent was estimated, and glutathione levels were also measured. Adaptive cytoprotection to 70% ethanol treatment was evaluated by measuring the gastric mucosal injury index in the presence or absence of the anti-oxidant.

RESULTS

The portal hypertensive gastric mucosa pretreated with 10% ethanol had significantly higher oxidative stress levels than the mucosa not pretreated with 10% ethanol. However, the sham-operated gastric mucosa pretreated with 10% ethanol had significantly lower oxidative stress levels than the mucosa not pretreated with 10% ethanol. Pretreatment with 10% ethanol increased glutathione levels in the sham-operated but not in the portal hypertensive gastric mucosa. Administration of the anti-oxidant agent prior to 10% ethanol pretreatment significantly reduced oxidative stress levels, increased glutathione levels, and decreased the injury index in response to 70% ethanol in the portal hypertensive gastric mucosa.

CONCLUSION

Increased oxidative stress may lead to impaired adaptive cytoprotection in the gastric mucosa of portal hypertensive rats, probably through damage to the system of endogenous anti-oxidant production.

Protective effect of l-citrulline against ethanol-induced gastric ulcer in rats

We examined the protective effect of l-citrulline on ethanol-induced gastric ulcer in rats. Administration of l-citrulline at doses of 300, 600 and 900mg/kg body weight prior to ethanol ingestion protected the stomach from ulceration. The gastric lesions were significantly attenuated by all doses of l-citrulline as compared to the ethanol group. Pre-treatment with l-citrulline prevented the oxidative damage and the decrease of nitric oxide content as well as the increase of the myeloperoxidase activity. Consequently, significant changes observed included the attenuation in the elevation in total nitric oxide synthase activity and inducible nitric oxide synthase activity as well as the decrease in constitutive nitric oxide synthase activity in the gastric mucosa induced by ethanol. Analysis of serum cytokines of ethanol-induced rats showed a moderate decrease in interleukin-10 with considerable increase of interleukin-6 while l-citrulline inhibited the acute alteration of cytokines. These results suggested the gastroprotective effect of l-citrulline.

Sulfated-polysaccharide fraction from red algae Gracilaria caudata protects mice gut against ethanol-induced damage

The aim of the present study was to investigate the gastroprotective activity of a sulfated-polysaccharide (PLS) fraction extracted from the marine red algae Gracilaria caudata and the mechanism underlying the gastroprotective activity. Male Swiss mice were treated with PLS (3, 10, 30 and 90 mg·kg⁻¹, p.o.), and after 30 min, they were administered 50% ethanol (0.5 mL/25 g⁻¹, p.o.). One hour later, gastric damage was measured using a planimeter. Samples of the stomach tissue were also obtained for histopathological assessment and for assays of glutathione (GSH) and malondialdehyde (MDA). Other groups were pretreated with l-NAME (10 mg·kg⁻¹, i.p.), dl-propargylglycine (PAG, 50 mg·kg⁻¹, p.o.) or glibenclamide (5 mg·kg⁻¹, i.p.). After 1 h, PLS (30 mg·kg⁻¹, p.o.) was administered. After 30 min, ethanol 50% was administered (0.5 mL/25g⁻¹, p.o.), followed by sacrifice after 60 min. PLS prevented-ethanol-induced macroscopic and microscopic gastric injury in a dose-dependent manner. However, treatment with l-NAME or glibenclamide reversed this gastroprotective effect. Administration of propargylglycine did not influence the effect of PLS. Our results suggest that PLS has a protective effect against ethanol-induced gastric damage in mice via activation of the NO/K_ATP pathway.

The effect of nitric oxide, growth factors, and estrogen on gastric cell migration

BACKGROUND

To study gastric epithelial cell migration during nitric oxide (NO) and growth factor treatment, simulating inflammation and infection. Also, the effects of estrogen on migration of different malignant and nonmalignant gastric epithelial cell lines were explored.

MATERIAL AND METHODS

Isolated primary cultured rabbit gastric epithelial cells, rat gastric mucosal cells, human gastric adenocarcinoma cells, and human colon adenocarcinoma cells (WiDr) were cultured to confluency in appropriate media (5% CO2, 37 degrees C). The cells were treated by hepatocyte growth factor (HGF), transforming growth factor-alpha (TGF-alpha) and keratinocyte growth factor (KGF), with and without sodium nitroprusside (SNP, NO donor) or 17beta-estradiol. Caspase-3 activity and cell viability and migration speed after wounding were measured.

RESULTS

HGF was the most potent growth factor to stimulate migration. SNP dose-dependently decreased the speed of migration. HGF and TGF-alpha were able to overcome the SNP-induced inhibition of migration, whereas KGF was not. SNP also induced caspase-3 activity, which was inhibited by HGF and TGF-alpha. 17beta-estradiol decreased migration in all epithelial cells, but the decrease was more profound in malignant cell lines. HGF could overcome the estrogen retarded migration.

CONCLUSIONS

Growth factors can overcome NO-induced retardation of cell migration and inhibit NO-induced caspase-3 activity, which altogether might also have physiological significance in in vivo inflammation and in gastric cancer. The more profound decrease in migration speed of gastric adenocarcinoma cell line may suggest that estrogen might be one of the protective factor against female gastric adenocarcinoma before menopausal age.

Gastroprotective effect of fructus evodiae water extract on ethanol-induced gastric lesions in rats

Fructus Evodiae is a widely used herbal medicine with anti-inflammatory and analgetic activities in China. The present study was designed to investigate the effect of Fructus Evodiae water extract (FE) on ethanol-induced gastric lesions in rats. Three hours before ethanol challenge, animals were intraperitoneally treated with FE (424.8 mg/kg, 141.6 mg/kg, and 47.6 mg/kg). Subsequently, we employed ex-vivo chamber technique to examine the effect of FE on gastric transmucosal potential difference (PD) changes. NO(x) (nitrate and nitrite) in gastric perfusate and gastric lesion index of whole glandular stomach were determined by intubation. The results showed that FE dose-dependently accelerated the recovery of PD reduction by ethanol, and increased NO(x) production in gastric perfusate. FE also inhibited gastric lesion formation in a dose-dependent manner. These results suggested that FE prevented ethanol-induced gastric mucosal lesions by strengthening the mucosal barrier integrity and increasing gastric mucosal nitric oxide (NO) synthesis.

Protective effect of a novel rice extract against ethanol-induced gastric mucosal injury in rat

The aim of this study was to investigate the protective action of rice extract on ethanol-induced mucosal damage in vivo and wound healing of epithelial cells in vitro. Also, the effect of rice extract on gastric mucosal prostaglandin E(2) level, HSP72 expression, gastric acid secretion, and contribution of vanilloid receptor-mediated action was studied. In addition, using cultured gastric mucosal cells (RGM-1), the effect of rice extract on cytoprotection and wound healing of epithelial cells was evaluated. Rice extract significantly reduced gastric mucosal damage produced by ethanol in vivo, and heat treatment (80 degrees C, 3 min) of this agent did not alter its protective effect. Rice extract also protected RGM-1 from ethanol-induced damage in a dose-dependent manner. Rice extract accelerated wound healing of gastric epithelial cells. Our results demonstrate that rice extract could be an alternative ulcer treatment that provides cytoprotection and enhancement of wound healing not dependent on acid secretion, prostaglandin E(2) level, HSP72 expression, or vanilloid receptors.

Effect of different cyclooxygenase inhibitors on gastric adaptive cytoprotection induced by 20% ethanol

In this study, we evaluated the effect of two different dosages of therapeutically prescribed nonsteroidal anti-inflammatory drugs (NSAIDs), ibuprofen, diclofenac, nimesulide, meloxicam, and celecoxib (ED80 for COX-1 and COX-2) on normal gastric mucosa and mucosa, previously exposed to 20% ethanol. At COX-2-inhibiting dosages, the NSAIDs tested were nonulcerogenic, and the same response profile was observed in "adapted" stomachs. Interestingly, low doses of nimesulide and celecoxib increase the levels of Prostaglandin E(2) and COX-2, and protect against subsequent 100% ethanol exposition, suggesting that these drugs may act as "mild irritants" to gastric mucosa. The ulcerogenic response to NSAIDs was prevented by the previous 20% ethanol exposition, probably the result of nitric oxide synthesis, because PGE(2) levels in gastric mucosa were reduced by these agents and a concomitant nitric oxide blockade reversed this protection.

Adaptive cytoprotection of gastric mucosa in rats after intragastric administration of edible alcohol

AIM: To observe the response to edible alcohol-induced injury and expression of prostaglandin E₂ (PGE₂), transforming growth factor-α (TGF-α) in gastric mucosa of rats.

METHODS: A total of 36 Sprague Dawley rats were divided group A, B, and C, intragastrically treated with edible alcohol (530 ± 20 mL/L), ethanol (530 mL/L), and normal saline at 5 mL/kg once every other day, respectively. The rats were killed at 1 week and 1 month after treatment, and the extent of mucosal injury was evaluated. Immunohistochemistry was used to examine the mucosal expression of TGF-α protein. Anther 36 rats were selected and treated as the method mentioned above, and the level of PGE₂ in gastric mucosa was determined by enzyme linked immunosorbent assay.

RESULTS: The most severe gastric mucosal injury was found in group C, then in group B, and the rats in group A were found with the mildest mucosal injury. The scores for mucosal injury were significantly different among group A, B and C 1 week (26.5 ± 6.4 vs 40.5 ± 8.1 vs 69.3 ± 4.3, all P < 0.05) and 1 month (34.8 ± 8.0 vs 54.8 ± 8.0 vs 74.8 ± 3.1, P < 0.05) after treatment. The level of mucosal PGE₂ was increased significantly in group A and B as compared with that in group C 1 wk after treatment (15.7 ± 1.4, 14.6 ± 1.9 ng/L vs 18.5 ± 2.7 ng/L, P < 0.05), but there was no difference between group A and B. One month after treatment, the level of PGE₂ was decreased in group A, not different from that in group C, but there was obvious difference between the former two groups and group B (15.7 ± 1.4, 14.6 ± 1.9 ng/L vs 18.5 ± 2.7 ng/L, P < 0.05). The expression of TGF-α was significantly lower in group A and B than that in group C 1 week after treatment (both P = 0), but no difference was found between group A and B. TGF-α expression was significantly different among group A, B, and C 1 month after treatment (P = 0.013, 0.001, and 0, respectively). The level of PGE₂ and the expression of TGF-α were notably different between 1 week and 1 month in group A and C, but not in group B.

CONCLUSION: Appropriate stimulus with edible alcohol and ethanol may lead to adaptive cytoprotection in gastric mucosa through up-regulation of PGE₂ and TGF-α.

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.

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Effect of acupuncture at different meridian acupoints on changes of related factors for rabbit gastric mucosal injury

AIM: To explore the regularity of multi-meridians controlling a same viscus (MMCSV).

METHODS: The rabbit gastric ulcer model was established by ethanol intragastric instillation. Fifty-six rabbits were randomly divided into normal group, model group (MG), model plus acupuncture at Foot Yangming Meridian group (YMG), model plus acupuncture at Foot Taiyin Meridian group (TYG), model plus acupuncture at Foot Shaoyang Meridian group (SYG), model plus acupuncture at Foot Jueyin Meridian group (JYG), model plus acupuncture at Foot Taiyang Meridian group (TYMG), with eight rabbits in each group. Gastric mucosal nitric oxide (NO) and nitric oxide synthase (NOS) were assayed by the nitric acid reductase method, and prostaglandin E2 (PGE2) and epidermal growth factor (EGF) were measured by radioimmunoassay. The comprehensive effects were analyzed by weighing method.

RESULTS: Compared to MG, SYG, JYG and TYMG, the rabbits gastric mucosal injury index (GMII) reduced very significantly in YMG (P<0.01). Compared to MG, the GMII also reduced significantly in TYG (P<0.05). NO, NOS, PGE2 and EGF increased very significantly in YMG (P<0.01). The EGF in YMG also increased significantly than that in TYG compared to those in MG, SYG, JYG and TYMG (P<0.05). The PGE2 and EGF also increased very significantly in TYG than those in MG, JYG and TYMG (P<0.01). While compared to SYG, the NOS increased significantly in TYG (P<0.05). NOS was the highest in YMG (P<0.01), and was higher in TYG than in MG (P<0.01).

CONCLUSION: MMCSV is common. The Foot Yangming Meridian is most closely related to the stomach, followed by Foot Taiyin Meridian, Foot Shaoyang Meridian and Foot Jueyin Meridian. Foot Taiyang Meridian has no correlation with the stomach.

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.