Protective effect of coadministered superoxide dismutase and catalase against stress-induced gastric mucosal lesions

Oxidative stress-induced by different stressors alters kidney tissue antioxidant markers and levels of creatinine and urea: the fate of renal membrane integrity

The cellular integrity of the kidney in homeostatic regulation has constantly been compromised by oxidative stress following exposure to varying nature of stressor present within the environment. The objective of the work was to evaluate the renal effect of the different stressor stimuli applied. Twenty-four adult female rats weighing averagely 160-200 g and within the ages of 12-14 weeks were used for experiment-1, while 12 offspring were utilized for experiment-2. Three stress models namely; restraint, mirror chamber and cat intruder stressors were used. Tissues were isolated from the animal and homogenized for tissue antioxidant assay. Serum was collected for assays of urea and creatinine for the kidney function test using ELISA. Data collected were analyzed for Mean ± SEM using One Way ANOVA. The present study revealed that exposure of rats to different stressors reduced relative kidney weights but did not significantly alter serum creatinine concentration in the Wistar rats, although the concentrations were slightly increased compared to controls. Urea concentration was significantly (p < 0.05) increased in rats exposed to restraint and intruder stressors. Exposure to a mirror chamber stressor did not significantly alter urea concentration. Offspring from parents of stressed female rats exhibited a significant (p < 0.05) increase in serum urea level, minimal increase in serum creatinine levels. GSH and GST levels showed no significant difference when compared to control group, whereas, GPx were significantly (p < 0.05) decreased irrespective of the stressor applied. SOD activity were significantly (p < 0.05) reduced in the group exposed to restraint or cat intruder stressor. CAT activities were significantly (p < 0.05) reduced in the rats exposed to restraint or cat intruder stressor. In all, the different stress model altered the antioxidant capacity of the kidney tissues. Exposure of rats to a stressful condition of the different nature of stressor has the tendency of compromising the functional integrity of the kidney, thus, with the potency of complicating female renal function.

Gastroprotective effects of nebivolol and simvastatin against cold restraint stress-induced gastric ulcer in rats

Gastric ulcer is one of the most serious diseases. Nebivolol (Neb), a β1-blocker, exhibits vasodilator and anti-oxidative properties, simvastatin (Sim) antihyperlipidemic drug, exhibits anti-oxidative, anti-inflammatory properties and promote endogenous nitric oxide (NO) production. The aim of this study was to evaluate the gastroprotective effects of Neb and Sim against cold restraint stress (CRS)-induced gastric ulcer in rats. Rats were restrained, and maintained at 4°C for 3 hours. Animals were divided into six groups; control group, CRS group, and four treatment groups received ranitidine (Ran), Neb, Sim and both Neb and Sim. Treatments were given orally on a daily basis for 7 days prior to CRS. The gastroprotective effects of Neb and Sim were assessed biochemically by measuring variations in prostaglandins E2, NO, reduced glutathione and malondialdehyde, and functionally by estimating force of contractions of isolated rat fundus in the studied groups in response to acetylecholine stimulation and morphologically using hematoxylin and eosin staining, periodic acid Schiff's reaction and immunohistochemistry for cyclooxygenase 2 in gastric mucosa. CRS caused significant ulcerogenic effect. Alternatively, pretreatment with Ran, Neb, and Sim significantly corrected biochemical findings, pharmacological and histological studies.

Incidence of hypoplastic posterior communicating artery and fetal posterior cerebral artery in Andhra population of India: a retrospective 3-Tesla magnetic resonance angiographic study

The posterior communicating arteries (PCoA) are important component of collateral circulation between the anterior and posterior part of circle of Willis (CW). The hypoplasia or aplasia of PCoA will reflect on prognosis of the neurological diseases. Precise studies of the incidence of hypoplastic PCoA in Andhra Pradesh population of India are hitherto unreported, since the present study was undertaken. Two hundred and thirty one magnetic resonance angiography (MRA) images were analyzed to identify the hypoplasia of PCoA and presence of fetal type of posterior cerebral artery (f-PCA) in patients with different neurological symptoms. All the patients underwent 3.0T MRI exposure. The results were statistically analysed. A total of 63 (27.3%) PCoA hypoplasia and 13 cases with f-PCA (5.6%) cases were identified. The hypoplastic PCoA was noted more in males than females (P<0.05) and right side hypoplasia was common than the left (P<0.04); bilateral hypoplasia of PCoA was seen in 37 cases out of 63 and is significant. The hypoplastic cases of the present study also were associated with variations of anterior cerebral arteries and one case was having vertebral artery hypoplasia. Incidence of PCoA as unilateral or bilateral with other associated anomalies of CW is more prone to develop stroke, migraine and cognitive dysfunction. Knowledge of these variations in the PCoA plays a pivotal role in diagnoses of neurological disorders and in neurovascular surgeries and angiographic point of view.

Comparative proteomic analysis of rats subjected to water immersion and restraint stress as an insight into gastric ulcers

In the present study, comparative proteomic analysis was performed in rats subjected to water immersion-restraint stress (WRS). A total of 26 proteins were differentially expressed and identified using matrix-assisted laser desorption/ionization time of flight mass spectrometry. Among the 26 differentially expressed protein spots identified, 13 proteins were significantly upregulated under WRS, including pyruvate kinase and calreticulin, which may be closely associated with energy metabolism. In addition, 12 proteins were downregulated under WRS, including hemoglobin subunit β-2 and keratin type II cytoskeletal 8, which may be important in protein metabolism and cell death. Gene Ontology analysis revealed the cellular distribution, molecular function and biological processes of the identified proteins. The mRNA levels of certain differentially expressed proteins were analyzed using fluorescence quantitative polymerase chain reaction analysis. The results of the present study aimed to offer insights into proteins, which are differentially expressed in gastric ulcers in stress, and provide theoretical evidence of a radical cure for gastric ulcers in humans.

Chronic restraint stress increases angiotensin II potency in the rat carotid: role of cyclooxygenases and reactive oxygen species

OBJECTIVES

To investigate the mechanisms underlying the effects of chronic restraint stress on the vascular contractile response induced by angiotensin (Ang) II in rat carotid.

METHODS

Concentration-response curves for AngII were obtained in endothelium-intact or endothelium-denuded carotid rings, in the absence or presence of SC-560 (COX-1 inhibitor), SC-236 (COX-2 inhibitor), wortmannin (PI₃ K-Akt inhibitor), ML171 (NOX-1 inhibitor), VAS2870 (NOX-4 inhibitor), tiron (O2- scavenger) or PEG-catalase (H₂ O₂ scavenger). 6-ketoPGF_1α , TXB₂ , O2- or H₂ O₂ levels and superoxide dismutase and catalase activity or expression were also measured in rat carotid.

KEY FINDINGS

Stress increased AngII potency in rat carotid. Muscular COX-1 or COX-2-derived metabolites negatively modulated AngII-induced contraction in control rat carotid. Endothelial COX-1 or COX-2-derived metabolites positively modulated AngII-induced contraction in stressed rat carotid. PI₃ K-Akt, NOX-1, NOX-4, O2- and H₂ O₂ positively modulated AngII-induced contraction in stressed rat carotid. Stress increased 6-ketoPGF_1α or H₂ O₂ generation and reduced catalase activity in rat carotid. Protein expression of COX-1, NOX-4 or p-Akt was increased in stressed rat carotid.

CONCLUSIONS

Stress increases AngII potency in rat carotid by a mechanism that involves the increased generation of PGI₂ and H₂ O₂ and the activation of Akt pathway. Such mechanism could play a pathophysiological role in cardiovascular diseases correlated with stress.

Helicteres sacarolha A. St.- Hil. et al.: gastroprotective and possible mechanism of actions in experimental animals

ETHNOPHARMACOLOGICAL RELEVANCE

Helicteres sacarolha A. St.- Hil. et al. popularly known in Brazil as 'semente-de-macaco', is widely employed in the popular medicine in many of parts of Brazil in the alleviation of symptoms of ailments such as peptic ulcer and inflammation. Up to the present, there is no study addressing the gastroprotective activity of the hydroethanolic extract of H. sacarolha and its possible mechanism of actions.

MATERIALS AND METHODS

The hydroethanolic (70%) extract of H. sacarolha (HEHs) was obtained by maceration. The gastroprotective activity was assessed using gastric ulcer models induced by acidified ethanol, piroxicam, and water restraint stress in mice and rats at doses of 20, 50 and 250mg/kg p.o. Mechanistic studies involved the antisecretory assay evaluated with pylorus ligation in rats and pre-treatments with appropriate antagonists/inhibitors such as yohimbine, glibenclamide, indomethacin and l-NAME, effect on catalase and myeloperoxidase activities and gastric mucus determination using acidified ethanol- induced ulcer in mice.

RESULTS

HEHs at all doses tested demonstrated potent gastroprotective activities in the acute ulcer models. The gastroprotective activity of HEHs was attenuated by pre-treatments with yohimbine, glibenclamide, indomethacin and l-NAME. HEHs effectively reduced basal gastric juice production without any effect on the free and total acidity. The gastroprotective action of HEHs involved increasing the antioxidant enzyme catalase and mucus secretion and inhibition of neutrophyl infiltration as reflected by the reduction in the myeloperoxidase activity.

CONCLUSION

The results of this study gave a scientific support for the popular use of the leaves of H. sacarolha in the treatment of gastric ulcers and that it has a multi-targeted action.

Vitamin E: a potential therapy for gastric mucosal injury

CONTEXT

Many scientific reports have shown the involvement of oxidative stress and inflammation as well as diminished gastroprotective substances in the pathogenesis of gastric lesions using various models. Therefore, treatment with antioxidants like tocopherol and tocotrienol may afford beneficial effects in attentuating the formation of the gastric lesions.

OBJECTIVE

The aim of this work was to summarize documented reports on the effects of vitamin E on various models of gastric lesion.

METHODS

A literature search was performed from databases in Medline (PubMed), Web of Science, ScienceDirect, and Googlescholar from June to December 2013.

RESULTS AND CONCLUSION

The potential roles of tocopherol and tocotrienol in modifying the effects of ulcerogenic agents are discussed in this review. The protective effects of the vitamin E might involve ameliorating oxidative stress and inflammation as well as restoration of endogenous gastroprotective substances. This vitamin has the potential to be used as a therapy for gastric mucosal injury.

Protective effects of oral administration of yeast thioredoxin against gastric mucosal injury

Thioredoxin (TRX) is a redox regulating protein which has protective effects against oxidative stress-induced damage to cells and tissues. In this study, we investigated the effects of orally administered TRX derived from edible yeast, Saccharomyces cerevisiae, on gastric mucosa. First, we examined the digestibility of orally administered yeast TRX in mice, and detected yeast TRX in the stomach for 4 h after administration. Next, we investigated the mitigation of gastric mucosal injury after the oral administration of yeast TRX in water-immersion restraint stress and HCl/ethanol-induced gastric ulcer models. Furthermore, we conducted DNA microarray analysis, using the HCl/ethanol-induced model, which revealed that several groups of genes related to tissue repair were upregulated in ulcer regions in the stomachs of rats administered with yeast TRX. These results demonstrated the viability of the use of oral administrations of yeast TRX to protect the gastric mucosa.

Effects of Bidens pilosa L. var. radiata Scherff on experimental gastric lesion

Bidens pilosa L. var. radiata Scherff: (BP) is a plant used as a traditional folk medicine. BP, cultivated with only green manure on Miyako Island, Okinawa prefecture, was processed to powder and is referred to as MMBP. We have reported that MMBP has antioxidant, anti-inflammatory, and anti-allergy properties. In this study, we investigated the effects of MMBP on several experimental gastric lesions induced by HCl/EtOH, a non-steroidal anti-inflammatory drug, or cold-restraint stress, comparing these results with those of rutin or anti-ulcerogenic drugs (cimetidine or sucralfate) based on the lesion index and hemorrhage from the gastric lesions. Orally administered MMBP prevented the progression of the gastric lesions. Moreover, treatment with MMBP, rutin, or sucralfate, which had potent antioxidative activity, inhibited increases in the levels of thiobarbituric acid reactive substances (TBARS) in the gastric mucosal lesions. The inhibition of the gastric mucosal TBARS content by MMBP may have been due to the antioxidant effects of MMBP. These results indicate that MMBP prevents the progression of acute gastric mucosal lesions, possibly by suppressing oxidative stress in the gastric mucosa.

Vitamin E protects against stress-induced gastric mucosal lesions in rats more effectively than vitamin C

In this study, we examined the protective effects of vitamin E (VE) against gastric mucosal lesions induced by water immersion restraint stress (WIRS) in rats in comparison with that of vitamin C (VC). The gastric mucosa of rats with 6 h of WIRS showed lesions with bleeding, decrease in nonprotein SH, VC, VE, and adherent mucus concentrations and constitutive nitric oxide synthase activity, and increase in lipid peroxide and NOx (nitrite/nitrate) concentrations and myeloperoxidase, xanthine oxidase, and inducible nitric oxide synthase activities. Either VE (0.05 or 0.5 mmol/kg) or VC (0.5 or 1.5 mmol/kg) was orally administered to rats with 6 h of WIRS just before the onset of the stress. Both doses of pre-administered VE prevented gastric mucosal lesion development and attenuated all these changes in gastric mucosal components and enzymes studied, whereas only the higher dose of pre-administered VC suppressed the changes in all parameters studied. These results indicate that orally administered VE protects against WIRS-induced gastric mucosal lesions in rats more effectively than orally administered VC. These results also suggest that the administered VE protects against gastric mucosal lesions in rats with WIRS through its antioxidant and anti-inflammatory actions in the gastric mucosa in the same way as the administered VC.

Mechanism of action of celecoxib on normal and acid-challenged gastric mucosa

Selective COX-2 inhibitor, celecoxib, delays the healing of gastric ulcers by inhibiting prostaglandins synthesis. Therefore, the effect of celecoxib on normal and acid-challenged gastric mucosa was studied. Wistar rats were distributed into four groups: group-1 (vehicle treated), group-2 (celecoxib treated), group-3 (given 0.6N HCl) and group-4 (HCl+celecoxib treated). The gastric mucosa was assessed histopathologically and by evaluating gastric adherent mucus. To assess the role of oxidative stress, the levels of free radicals and antioxidants were measured. The histopathological examination showed mild inflammation in group-2, moderate inflammation in group-3 and severe inflammation in group-4. The results showed an increase in malondialdehyde and a decrease in gastric adherent mucus, nitrite, reactive thiols and glutathione in groups-2-4 as compared to control group. Activity of superoxide dismutase, catalase and glutathione-s-transferase was increased in all the groups except the group-1. The present study suggested that celecoxib aggravated the gastric damage caused by acid which may be mediated by altering the balance between free radicals and antioxidants.

Effect of oral vitamin E administration on acute gastric mucosal lesion progression in rats treated with compound 48/80, a mast cell degranulator

The effect of oral vitamin E administration on acute gastric mucosal lesion progression was examined in rats treated once with compound 48/80 (C48/80) (0.75 mg/kg, i.p.) in comparison with that of subcutaneously administered superoxide dismutase (SOD) plus catalase (CAT). Vitamin E (50, 100 or 250 mg/kg) administered at 0.5 h after C48/80 treatment reduced progressive gastric mucosal lesions at 3 h after the treatment dose-dependently, like SOD plus CAT administered at the same time point. The gastric mucosa of C48/80-treated rats had decreased Se-glutathione peroxidase activity and vitamin E, ascorbic acid, and hexosamine contents and increased myeloperoxidase and xanthine oxidase activities and thiobarbituric acid reactive substances content at 3 h after the treatment. Administered vitamin E attenuated all these changes found at 3 h after C48/80 treatment dose-dependently, like administered SOD plus CAT. C48/80-treated rats administered with vitamin E (100 or 250 mg/kg) had higher gastric mucosal vitamin E content than C48/80-untreated rats. Neither administered vitamin E nor SOD plus CAT had any effect on the increases in serum serotonin and histamine concentrations and the decrease in gastric mucosal blood flow found at 3 h after C48/80 treatment. In the gastric mucosa of C48/80-untreated rats administered with vitamin E, thiobarbituric acid reactive substances content decreased with an increase in vitamin E content. These results indicate that orally administered vitamin E prevents acute gastric mucosal lesion progression in C48/80-treated rats possibly by suppressing oxidative stress, neutrophil infiltration, and mucus depletion in the gastric mucosa like administered SOD plus CAT.

Role of gastric mucosal ascorbic acid in gastric mucosal lesion development in rats with water immersion restraint stress

We examined the role of gastric mucosal ascorbic acid (AA) in gastric mucosal lesion development in rats with water immersion restraint stress (WIRS). When fasted rats were subjected to WIRS for 1, 3 or 6 h, gastric mucosal lesions developed at 3 and 6 h. Gastric mucosal AA concentration decreased at 3 and 6 h after the onset of WIRS, while gastric mucosal non-protein SH concentration decreased at 1, 3, and 6 h and gastric mucosal vitamin E concentration decreased at 6 h. Gastric mucosal lipid peroxide concentration and myeloperoxidase activity increased at 3 and 6 h of WIRS. Pre-administration of AA (250 mg/kg) prevented gastric mucosal development with attenuation of the decreased gastric mucosal AA, non-protein SH and vitamin E concentrations, and the increased gastric mucosal lipid peroxide concentration and myeloperoxidase activity. These results suggest that gastric mucosal AA plays an important role in WIRS-induced gastric mucosal lesion development.

Peri-sciatic proinflammatory cytokines, reactive oxygen species, and complement induce mirror-image neuropathic pain in rats

In inflammatory neuropathy, immune activation near intact peripheral nerves induces mechanical allodynia. The identity of the peripheral immune product(s) that lead to these changes in pain behavior is unknown. The present series of studies utilized the sciatic inflammatory neuropathy (SIN) model to examine this question. Here, inflammatory neuropathy is created by injecting an immune activator (zymosan) around one sciatic nerve via an indwelling catheter. Our prior studies demonstrated that peri-sciatic zymosan activated macrophages and neutrophils to release proinflammatory cytokines and reactive oxygen species (ROS). In addition, zymosan is a classical activator of the complement cascade. Thus the present series of experiments examined whether any of these inflammatory mediators are involved in the initial induction of SIN-induced ipsilateral or bilateral allodynias. Peri-sciatic injection of selective inhibitors/antagonists revealed that a number of immune products are early mediators of the resultant allodynias, including proinflammatory cytokines (tumor necrosis factor, interleukin-1, and interleukin-6), ROS, and complement. Thus these immune-derived substances can markedly alter sensory nerve function at mid-axon.

Effects of Ginkgo biloba extract on cytoprotective factors in rats with duodenal ulcer

AIM: To investigate the effects of Ginkgo biloba extract on cytoprotective factors in rats with duodenal ulcer.

METHODS: Sprague-Dawley rats were randomly divided into four groups: sham operation without ginkgo, sham operation with ginkgo, duodenal ulcer without ginkgo, and duodenal ulcer with ginkgo. Rats with duodenal ulcer were induced by 500 mL/L acetic acid. Rats with ginkgo were intravenously injected with Ginkgo biloba extract from the tail at a dose of 0.5 mg/(kg·d) for 7 and 14 days.

RESULTS: Pathological result showed that duodenal ulcer rats with ginkgo improved mucosal healing and inflammation compared with those without ginkgo after 7 d treatment. After 14 d treatment, duodenal ulcer rats with ginkgo significantly increased weight gain (34.0 ± 4.5 g versus 24.5 ± 9.5 g, P < 0.05) compared with those without ginkgo. Duodenal ulcer rats significantly increased cell proliferation (27.4 ± 4.0 and 27.8 ± 2.3 BrdU-labeled cells in duodenal ulcer rats with and without ginkgo versus 22.4 ± 3.5 and 20.8 ± 0.5 BrdU-labeled cells in sham operation rats with and without ginkgo, P < 0.05) compared with sham operation rats. Mucosal prostaglandin E₂ concentration significantly increased by 129% (P < 0.05) in duodenal ulcer rats with ginkgo compared with that in those without ginkgo. Duodenal ulcer rats without ginkgo significantly decreased superoxide dismutase activity in the duodenal mucosa and erythrocytes (19.4 ± 6.7 U/mg protein versus 38.1 ± 18.9 U/mg protein in the duodenal mucosa, and 4.87 ± 1.49 U/mg protein versus 7.78 ± 2.16 U/mg protein in erythrocytes, P < 0.05) compared with sham operation rats without ginkgo. However, duodenal ulcer rats with ginkgo significantly increased erythrocyte superoxide dismutase activity (8.22 ± 1.92 U/mg protein versus 4.87 ± 1.49 U/mg protein, P < 0.05) compared with those without ginkgo. Duodenal ulcer rats without ginkgo significantly increased plasma lipid peroxides (4.18 ± 1.12 μmol/mL versus 1.60 ± 1.10 μmol/mL and 1.80 ± 0.73 μmol/mL, P < 0.05) compared with sham operation rats without ginkgo and duodenal ulcer rats with ginkgo during the experimental period.

CONCLUSION: Ginkgo biloba extract can improve weight gain and mucosal healing in duodenal ulcer rats by the actions of cytoprotection and antioxidation.