Preventive effect of hydrotalcite on gastric mucosal injury in rats induced by taurocholate

AIM: To study the preventive effect of hydrotalcite on gastric mucosal injury in rat induced by taurocholate, and to investigate the relationship between the protective mechanism of hydrotalcite and the expression of trefoil factor family 2 (TFF2) mRNA and c-fos protein.METHODS: Forty five male Wistar rats were randomly divided into hydrotalcite group, ranitidine group and control group. Gastric mucosal injury was induced by introgastric acidified taurocholate. OD value of TFF2 mRNA expression in gastric mucous cells was determined by hybridization and computer image analysis system. OD value of c-fos protein expression in gastric mucous cells was measured by immunohistochemistry and computer image analysis system.RESULTS: The gross mucosal injury index in hydrotalcite group was significantly lower than that in ranitidine group and control group (8.60±2.20 vs 16.32±4.27, 29.53±5.39;P＜0.05, P＜0.01). The expression level of TFF2 mRNA in hydrotalcite group was markedly higher than that in ranitidine group and control group (0.56±0.09 vs 0.30±0.05, 0.28±0.03,P＜0.05). The OD value of c-fos protein in hydrotalcite group was higher than that in ranitidine group and control group (0.52±0.07 vs 0.31±0.04, 0.32±0.05, P＜0.05).CONCLUSION: Hydrotalcite can protect gastric mucosal injury in rats induced by taurocholate, which may be related to the increased expression of TFF2 and c-fos protein.     

Effects of dopamine on gastric mucosal lesions induced by ethanol in rats

Acidified ethanol (60% ethanol in 150 mM HCl, per os) induced elongated bands of hemorrhagic lesions along the long axis of the stomach within 1 hr in rats. Pretreatment with dopamine hydrochloride (DA: 1-10 mg/kg, subcutaneously) dose-dependently reduced the severity of these lesions. In parallel study, DA had no effect on acid secretion but inhibited gastric motor activity in a dose-related manner. The inhibitory effects of DA on both acidified ethanol-induced lesions and gastric motor activity were significantly reversed by pretreatment with yohimbine, an inhibitor of alpha 2-adrenoceptors (5 mg/kg, subcutaneously), but not by prazosin, haloperidol, or indomethacin. Similar to DA, both norepinephrine (NE: 1 mg/kg, subcutaneously) and epinephrine (EPI: 1 mg/kg, subcutaneously) showed inhibition of the motor activity and gastroprotection against acidified ethanol, but these effects were also significantly attenuated by yohimbine. A highly significant relationship was found between the inhibitory effects of DA, NE, and EPI on the motor activity and the mucosal lesions (r = 0.8577, P less than 0.05). In addition, administration of gentian violet (0.5% w/v, per os) stained the mucosa deep blue as elongated wide bands in the corpus region, and such localized staining was significantly prevented by DA, suggesting a flattening of the mucosal foldings in the presence of DA. These results suggest that DA (and other catecholamines) protects the rat gastric mucosa against injury caused by acidified ethanol, probably through inhibition of gastric motor activity mediated with stimulation of alpha 2-adrenoceptors.     

聚普瑞锌诱导HSP70保护大鼠胃黏膜损伤

目的探讨聚普瑞锌诱导热休克蛋白70(heat shock protein 70,HSP70)减轻大鼠胃黏膜损伤的作用机制。方法无水乙醇灌胃致大鼠胃黏膜损伤后分别应用聚普瑞锌100 mg/kg、200 mg/kg灌胃及赋形剂灌胃,同时以空白组作对照,检测胃黏膜HSP70蛋白表达。同时检测各实验组大鼠胃黏膜IGF-1含量和SOD活性。结果聚普瑞锌100 mg/kg治疗组治疗3 d时HSP70表达的相对灰度值为278.3%±10.8%;聚普瑞锌200 mg/kg治疗组治疗3 d时HSP70表达的相对灰度值为471.1%±24.7%,与空白组和赋形剂组相比,差异均有统计学意义(P0.01)。各实验组大鼠胃黏膜IGF-1含量和SOD活性差异无统计学意义(P0.05)。结论聚普瑞锌能够诱导损伤后大鼠胃黏膜产生大量HSP70,发挥保护胃黏膜的作用。     

Effect of capsaicin and chilli on ethanol induced gastric mucosal injury in the rat.

Capsaicin, the pungent ingredient of chilli, is gastroprotective against experimental gastric injury when given intragastrically. Epidemiological and clinical data suggest that chilli ingestion may have a beneficial effect on human peptic ulcer disease. This study showed a gastroprotective effect of intragastric capsaicin, in doses of 2 and 5 mg, on ethanol induced gastric mucosal injury using macroscopic, histological, scanning electron microscopic, and biochemical indices. Subcutaneous administration of 2 mg of capsaicin had the same gastroprotective effect as intragastric administration. Acute intragastric administration and chronic ingestion of chilli powder in doses comparable with that consumed in humans (up to 200 mg in single doses or 200 mg daily for four weeks) likewise protected the gastric mucosa. Both the mucosa and gastric juice had higher mucus contents when capsaicin or chilli rather than saline or solvent was used before ethanol challenge. In control animals capsaicin also increased gastric juice mucus content although the mucosal content was unaffected. Increased gastric mucus production may therefore be one mechanism by which capsaicin and chilli exert their gastroprotective effect although an alternative explanation is that the reduction in mucosal mucus depletion is secondary to the protective effect of capsaicin and chilli.     

Role of Superoxide and hydroxyl radicals in rat gastric mucosal injury induced by ethanol

It has been reported that oxygen-derived free radicals play an important role in the pathogenesis of mucosal injury in the small intestine as well as in the stomach. The aims of this study were to test whether ethanol-induced damage in the rat stomach was prevented by the administration of (1) Superoxide dismutase (SOD; a scavenger of Superoxide radicals), (2) allopurionol (ALP; an inhibitor of xanthine oxidase), (3) dimethyl sulfoxide (DMSO; a scavenger of hydroxyl radicals). SOD significantly decreased the ulcer index from 100±8.5% (control) to 39.6±8.2% (P<0.001). Ethanol-induced damage was reduced by the administration of ALP by 37.4% (P<0.01). DMSO also diminished the ulcer index from 100±8.5% (control) to 31.6±5.8% (P<0.01). Histochemical studies supported these results. A scanning EM study, however, revealed that surface epithelial cells were not protected by SOD against ethanol-induced damage. These results demonstrated that SOD, ALP and DMSO had the ability to protect gastric mucosa against ethanol-induced injury. Accordingly, oxygen-derived free radicals may be involved in the pathogenesis of ethanol-induced gastric mucosal damage. Surface epithelial cells, however, were not protected even by SOD against ethanol-induced injury. This paper was presented in 87th Annual Meeting of American Gastroenterological Association (1986).     

Role of superoxide and hydroxyl radicals in rat gastric mucosal injury induced by ethanol

It has been reported that oxygen-derived free radicals play an important role in the pathogenesis of mucosal injury in the small intestine as well as in the stomach. The aims of this study were to test whether ethanol-induced damage in the rat stomach was prevented by the administration of (1) superoxide dismutase (SOD; a scavenger of superoxide radicals), (2) allopurionol (ALP; an inhibitor of xanthine oxidase), (3) dimethyl sulfoxide (DMSO; a scavenger of hydroxyl radicals). SOD significantly decreased the ulcer index from 100 +/- 8.5% (control) to 39.6 +/- 8.2% (P less than 0.001). Ethanol-induced damage was reduced by the administration of ALP by 37.4% (P less than 0.01). DMSO also diminished the ulcer index from 100 +/- 8.5% (control) to 31.6 +/- 5.8% (P less than 0.01). Histochemical studies supported these results. A scanning EM study, however, revealed that surface epithelial cells were not protected by SOD against ethanol-induced damage. These results demonstrated that SOD, ALP and DMSO had the ability to protect gastric mucosa against ethanol-induced injury. Accordingly, oxygen-derived free radicals may be involved in the pathogenesis of ethanol-induced gastric mucosal damage. Surface epithelial cells, however, were not protected even by SOD against ethanol-induced injury.     

Role of endogenous gastric mucosal prostaglandins in the formation of acute gastric mucosal lesions induced by aspirin, ethanol, HCl and CH3COOH

The role of endogenous mucosal prostaglandins (PGs) in the production of acute gastric mucosal lesions (AGML) was examined in rats. Aspirin, ethanol or 0.6 N-HCl was given intragastrically and 20% acetic acid was injected into the gastric wall. Endogenous gastric mucosal PG (A + B), PGE and PGF were determined by radioimmunoassay. Their gastric contents were markedly reduced by aspirin administration (p less than 0.001). The level of gastric mucosal PGs still remained low (p less than 0.001) after the aspirin-induced AGML began to heal. Furthermore, rats with AGML induced by ethanol, HCl or acetic acid, showed no decrease in endogenous gastric mucosal PGs compared with the controls. These findings indicated that endogenous PGs are not necessary for either the induction or healing of experimental AGML.     

Protection of gastric mucosa from ethanol induced injury by recombinant epidermal growth factor in rats

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Studies on gastric mucosal microcirculation. 1. The nature of regional variations induced by ethanol injury.

BACKGROUND/AIMS: The focal nature of gastric ulcers raises the possibility of underlying regional disturbances in gastric mucosal microcirculation. This study employed fluorescent in vivo microscopy with the aim of directly investigating the response of several areas of the gastric mucosa to 60% ethanol. METHODS: Changes in macromolecular leakage of fluorescein labelled albumin, vessel diameter, and acridine red labelled leucocyte adhesion and rolling were assessed over a period of two hours. A total of 0.5 ml 60% ethanol was topically applied for five minutes to the exteriorised gastric mucosa of anaesthetised rats. RATS: Three distinct patterns of response were found. Areas of lesion formation were small and occurred within five minutes. These areas showed persistent blood flow stasis throughout the course of the experiment, increased leakage (p < 0.02), and no leucocyte adhesion. Peripheral to the lesion, sustained leakage (p < 0.02) was found with adherence of leucocytes (p < 0.01) after lesion formation. Sites more remote to any lesion showed transient leakage and significant numbers of 'rolling' leucocytes (p < 0.01) were observed again after the lesion had formed. CONCLUSIONS: Despite widespread exposure of the entire gastric mucosa to 60% ethanol the resultant mucosal injury was limited. Widespread vascular damage was found reflected by macromolecular leakage, the pattern of which showed regional variation.     

Autofluorescence in onset of gastric mucosal injury induced by hemorrhagic shock in rats

In an attempt to clarify whether gastric mucosal autofluorescence can help us to recognize gastric lesions at the onset of their formation, we investigated the fluorescence generated from the gastric mucosa of rats under ischemia-reperfusion stress. Redcolored fluorescence appeared and began to increase within 5 min after reperfusion. Such an increase in fluorescence did not occur in the gastric mucosa under prolonged ischemia without reperfusion. The epifluorescence microscopy of mucosal cryosections revealed that fluorescence was present even when only superficial mucosal damage occurred. Spectrofluorometric and high-performance liquid chromatographic analysis of the fluorescent mucosa extract identified the fluorescent substances as porphyrins. These findings suggested that fluorescent porphyrins are generated in the mucosal layer during the introductory phase of mucosal lesion formation induced by ischemia-reperfusion stress.     

Protective effect of Polyalthia longifolia var. pendula leaves on ethanol and ethanol/HCl induced ulcer in rats and its antimicrobial potency

ObjectiveTo explore antiulcer and antimicrobial properties of methanolic extract of Polyalthia longifolia var. pendula.MethodsGastroprotective potential of Polyalthia longifolia was studied on ethanol and ethanol/HCl induced ulcers at 2 different doses (270 and 540 mg/kg/body weight). Antimicrobial efficacy of Polyalthia longifolia (25 mg/mL) was also studied against six gram positive, seven gram negative bacteria and five fungi by agar well diffusion method. Minimum inhibitory concentration was determined by agar well diffusion method in two fold serial dilution, in the range of 97-25 000 μg/mL.ResultsThe reduction of ulcer index in Polyalthia longifolia treated animals was found to be statistically significant with respect to control animals. The Polyalthia longifolia exhibited ulcer protection activity in dose dependent manner and was also better than the standard. In antimicrobial activity, gram positive bacteria were more susceptible to Polyalthia longifolia than gram negative bacteria and fungal strains.ConclusionsResults obtained confirm the antiulcer and antimicrobial potential of the Polyalthia longifolia.     

海带多糖对内皮细胞损伤大鼠模型的保护作用

目的探讨海带多糖对肾上腺素（Adr）致血管内皮细胞损伤的保护作用。方法皮下注射Adr建立血管内皮细胞损伤大鼠模型，主动脉切片免疫组化检测血管内皮受损情况，ELISA法测定大鼠血浆血管性血友病因子（von Willebrand factor，vWF）含量；体外培养人脐静脉内皮细胞（HUVEC），ELISA法测定HUVEC培养液vWF含量，观察海带多糖对内皮细胞损伤大鼠和Adr刺激HUVEC后vWF生成的影响。结果造模第4天和第5天主动脉切片免疫组化检测完整内皮层长度显示，海带多糖高剂量（50mg／kg）、低剂量（10mg／kg）组长度明显高于模型组（P〈0．05）；造模第4天，海带多糖高剂量组大鼠血浆vWF水平与模型组比较有显著差异（P〈0．05），第5天海带多糖高、低剂量组均呈现出同样的结果（P〈0．05）。在HUVEC培养实验中，终浓度为0．01mg／ml和0．1ms／mi的海带多糖均能降低24h培养液vWF水平，终浓度为0．1ms／mi海带多糖还能降低48h培养液vWF水平，与Adr组比较有显著差异（P〈0．05）。结论海带多糖对血管内皮细胞具有保护作用。     

还原型谷胱甘肽对正加速度暴露下急性胃黏膜损伤大鼠胃黏膜的影响

目的研究还原型谷胱甘肽(GSH)对正加速度(+Gz)暴露下急性胃黏膜损伤大鼠胃黏膜的影响及可能机制。方法 40只雄性SD大鼠随机分成4组:无水乙醇对照组(A组)、+5 Gz值暴露组(B组)、+10 Gz值暴露组(C组)、GSH预处理组(D组),每组10只。D组适应性喂养7 d后,连续3 d腹腔注射GSH。4组均于10 d后禁食24 h,禁水12 h,用无水乙醇灌胃1 h后,A组不受+Gz作用,B组暴露于+5 Gz值3 min,C、D组暴露于+10 Gz值3 min,下离心机后观察各组胃黏膜损伤情况,并检测胃黏膜中丙二醛(MDA)、GSH的含量及谷胱甘肽过氧化物酶(GSH-Px)的活性。结果各组大鼠胃黏膜在肉眼观察均有损伤,损伤程度:+10Gz值暴露组+5 Gz值暴露组无水乙醇对照组GSH预处理组,B组与A组相比差异均有统计学意义(P均0.05),C组分别与A、B两组相比差异均有统计学意义(P0.05);D组胃黏膜损伤最轻,与C组相比差异有显著统计学意义(P0.01)。与A组相比,B组胃黏膜中MDA、GSH含量变化不明显,差异均无统计学意义(P均0.05),GSH-Px活性明显升高,差异有显著统计学意义(P0.01);与A、B两组相比,C组胃黏膜中MDA含量升高明显,GSH含量降低明显,GSH-Px活性明显降低,差异均有统计学意义(P0.05);与C组相比,D组胃黏膜MDA含量明显降低,GSH的含量明显升高,GSH-Px的活性明显升高,差异有统计学意义(P0.05)。结论 GSH对+Gz值暴露引起的急性胃黏膜损伤大鼠的胃黏膜有预防及保护作用,该作用可能是通过增加胃黏膜GSH的含量、GSH-Px的活性及抑制MDA的作用而实现的。     

Can misoprostol and omeprazole reduce nicotine and ethanol induced gastric mucosal injury? A quantitative macroscopic and microscopic analysis in rats

We compared the effects of misoprostol, omeprazole and methylcellulose (control) on gastric mucosal injury induced by nicotine and/or ethanol. The results demonstrate that misoprostol and omeprazole each significantly reduce macroscopic injury and deep injury at a microscopic level (P < 0.05) induced by nicotine alone, ethanol alone or a combination of ethanol and nicotine. Misoprostol and omeprazole each reduced the leakage of fluorescein isothiocyanate-albumin into the interstitium in the gastric mucosa. Misoprostol and omeprazole are each effective in preventing injury induced by nicotine and ethanol and vascular factors are involved.     

Protective action of omeprazole against gastric mucosal injury induced by hemorrhagic shock in rats

The efficacy of omeprazole in preventing gastric mucosal injury induced by hemorrhagic shock in rats and the putative mechanisms involved in this effect were investigated in the present study. Omeprazole did not affect mean arterial blood pressure under both basal conditions and induction of hemorrhagic shock, but it evoked a marked increase in Alcian blue recovery from gastric preepithelial mucus. The morphometric analysis of histological sections revealed that omeprazole caused a significant reduction of hemorrhagic shock-induced damage of gastric mucosa. Ranitidine, used as the reference drug, failed to affect mean arterial blood pressure, Alcian blue recovery from gastric mucus, or hemorrhagic shock-induced damage of gastric mucosa. Both omeprazole and ranitidine exerted a significant inhibition of gastric acid output from anesthetized pylorus-ligated rats. Overall, the present results indicate that omeprazole is effective in protecting gastric mucosa from necrotic damage induced by hemorrhagic shock and suggest that an enhancement of gastric mucus secretion contributes to this protective action.     

Protective effect of vitamin E on gastric mucosal injury in rats with biliary obstruction.

Patients with liver disease display increased susceptibility to gastric mucosal damage. A role of free radicals has been suggested in the development of gastric mucosal damage in normal subjects. The effects of antioxidant vitamin E treatment on the liver and stomach in cirrhotic rats were examined. Fifty rats were divided into three groups. Cirrhosis was induced by bile duct ligation in 40 of 50 rats. Controls underwent a sham operation. Gastric mucosal lesions were produced by intragastric administration of 1 mL of 95% ethanol in all three groups. Twenty bile duct-ligated rats were injected intramuscularly with vitamin E (100 mg/kg/day). Liver and stomach histology, and stomach malondialdehyde and glutathione levels were determined. Portal hypertension was measured. Macroscopic and microscopic gastric mucosal injury were significantly greater in the control and common bile duct-ligated groups than in the vitamin E-pretreated group (P<0.05). The tissue malondialdehyde and glutathione levels were significantly decreased in the vitamin E-administrated group compared with the common bile duct-ligated group (P<0.001). Vitamin E administration may be cytoprotective for both the liver and gastric mucosa in bile duct-ligated rats.     

The protective effect of ginsenoside Rb1 pre-treatment on myocardial ischemia/reperfusion injury in Sprague-Dawley rats

Background Myocardial ischemia/reperfusion injury(MI/RI)during myocardial infarction worsens outcomes. It has been proved that ginsenoside Rb1 has a great impact on ischemia/reperfusion(I/R)injury. The aim of this study is to explore the protective effect of the pretreatment with ginsenoside Rb1 on MI/RI and investigate the underlying mechanisms about the preventive action. Methods A total of 27 healthy adult Sprague-Dawley(SD)rats were randomly divided into 3 groups(n=9 per group):A sham-operated group(Sham n=9);an ischemia 40 min/reperfusion 2 h(I/R n=9)of the cardiac muscle group;Rb1-treated group was divided into 3 subgroups(Rb1 10 mg/kg,20 mg/kg,40 mg/kg,n=3). Ginsenosides Rb1 at different concentrations were injected intraperitoneally for 3 days continuously before ligation. A model of MI/RI was constructed by ligation of the left coronary artery anterior descending branch in rats. Myocardial infarction area after I/R was measured bytriphenyltetrazolium chloride(TTC)staining of myocardial tissue. Hematoxylin and eosin(HE)staining and electrocardiogram indication were used to observe myocardial cell injury and ischemia,respectively. The expression of caspase-8 protein was observed by immunohistochemistry staining. Results The pretreatment of 40 mg/kg dose of ginsenoside Rb1 could decrease the expression of caspase-8 protein caused by I/R and the apoptosis of myocardial cells,improve myocardial ischemia,reduce the area of myocardial infarction and ameliorate MI/RI.Conclusions These results demonstrate that ginsenoside Rb1 has a significant protective effect on MI/RI through attenuating the apoptosis of myocardial cells and improving myocardial ischemia at appropriate dose,which provides new insights into the potential therapy of MI/RI.