Water-immersion Stress Research Articles

Protective Effects of Some Graded Iranian Honey Samples Against Cold Water Immersion‐Induced Gastric Ulcers in Rats

ABSTRACTHoney has a rich history of treating gastrointestinal diseases due to its diverse bioactive compounds. This study evaluated the protective effects of select Iranian honeys against cold water immersion stress (CWIS)‐induced ulcers in rats. Forty male Wistar rats (250–280 g) were randomly assigned to eight groups (n = 5): control, CWIS, and groups treated with strong (eucalyptus, Annaab, and Jangale) and weak honeys (Chand Giah, Sumaq, Gaz) + CWIS. Honey selection was based on antioxidant capacity, phenolic content, and protein concentration. Rats received 20% honey in water (1 mL/kg) orally twice daily for 14 days; controls received water. After a 24‐h fast, rats underwent 3‐h CWIS to induce ulcers. Serum samples were analyzed for malondialdehyde (MDA), total antioxidant capacity (TAC), thiol groups, tumor necrosis factor alpha (TNF‐α), and interleukin 6 (IL‐6) levels. Stomachs were assessed for ulcer severity (gastric ulcer index), gastric juice volume, and histopathological changes. Honey types were categorized as strong (eucalyptus, Annaab, and Jangale) or weak (Chand Giah, Sumaq, and Gaz) based on total phenolic content, antioxidant effects (FRAP and DPPH), and protein levels. Ulcer group showed significant increases in MDA (64%) and TNF‐α and IL‐6 levels (98.5% and 111.6%), and decreases in ferric reducing antioxidant power and 2,2‐diphenyl‐1 picrylhydrazyl (FRAP, DPPH, and thiol levels [26%, 14.39%, and 26%]) compared to controls. Strong honey groups exhibited 50% lower gastric ulcer index compared to weak honey groups. This study showed that strong honeys, due to their higher phenolic, total protein, and antioxidant content, offer greater protection against gastric damage and oxidative stress compared to weaker honeys. These results highlight the importance of bioactive compounds in honey's therapeutic properties. Therefore, high‐quality honeys with higher phenolic content can be considered as therapeutic supplements for gastrointestinal disorders, especially those caused by oxidative stress and inflammation.

Musclin prevents depression-like behavior in male mice by activating urocortin 2 signaling in the hypothalamus.

Physical activity is recommended as an alternative treatment for depression. Myokines, which are secreted from skeletal muscles during physical activity, play an important role in the skeletal muscle-brain axis. Musclin, a newly discovered myokine, exerts physical endurance, however, the effects of musclin on emotional behaviors, such as depression, have not been evaluated. This study aimed to access the anti-depressive effect of musclin and clarify the connection between depression-like behavior and hypothalamic neuropeptides in mice. We measured the immobility time in the forced swim (FS) test, the time spent in open arm in the elevated-plus maze (EPM) test, the mRNA levels of hypothalamic neuropeptides, and enumerated the c-Fos-positive cells in the paraventricular nucleus (PVN), arcuate nucleus (ARC), and nucleus tractus solitarii (NTS) in mice with the intraperitoneal (i.p.) administration of musclin. Next, we evaluated the effects of a selective corticotropin-releasing factor (CRF) type 1 receptor antagonist, selective CRF type 2 receptor antagonist, melanocortin receptor (MCR) agonist, and selective melanocortin 4 receptor (MC4R) agonist on changes in behaviors induced by musclin. Finally we evaluated the antidepressant effect of musclin using mice exposed to repeated water immersion (WI) stress. We found that the i.p. and i.c.v. administration of musclin decreased the immobility time and relative time in the open arms (open %) in mice and increased urocortin 2 (Ucn 2) levels but decreased proopiomelanocortin levels in the hypothalamus. The numbers of c-Fos-positive cells were increased in the PVN and NTS but decreased in the ARC of mice with i.p. administration of musclin. The c-Fos-positive cells in the PVN were also found to be Ucn 2-positive. The antidepressant and anxiogenic effects of musclin were blocked by central administration of a CRF type 2 receptor antagonist and a melanocortin 4 receptor agonist, respectively. Peripheral administration of musclin also prevented depression-like behavior and the decrease in levels of hypothalamic Ucn 2 induced by repeated WI stress. These data identify the antidepressant effects of musclin through the activation of central Ucn 2 signaling and suggest that musclin and Ucn 2 can be new therapeutic targets and endogenous peptides mediating the muscle-brain axis.

Effect of exogenous hydrogen sulfide in the nucleus tractus solitarius on gastric motility in rats.

Hydrogen sulfide (H2S) is a recently discovered gaseous neurotransmitter in the nervous and gastrointestinal systems. It exerts its effects through multiple signaling pathways, impacting various physiological activities. The nucleus tractus solitarius (NTS), a vital nucleus involved in visceral sensation, was investigated in this study to understand the role of H2S in regulating gastric function in rats. To examine whether H2S affects the nuclear factor kappa-B (NF-κB) and transient receptor potential vanilloid 1 pathways and the neurokinin 1 (NK1) receptor in the NTS. Immunohistochemical and fluorescent double-labeling techniques were employed to identify cystathionine beta-synthase (CBS) and c-Fos co-expressed positive neurons in the NTS during rat stress. Gastric motility curves were recorded by inserting a pressure-sensing balloon into the pylorus through the stomach fundus. Changes in gastric motility were observed before and after injecting different doses of NaHS (4 nmol and 8 nmol), physiological saline, Capsazepine (4 nmol) + NaHS (4 nmol), pyrrolidine dithiocarbamate (PDTC, 4 nmol) + NaHS (4 nmol), and L703606 (4 nmol) + NaHS (4 nmol). We identified a significant increase in the co-expression of c-Fos and CBS positive neurons in the NTS after 1 h and 3 h of restraint water-immersion stress compared to the expressions observed in the control group. Intra-NTS injection of NaHS at different doses significantly inhibited gastric motility in rats (P < 0.01). However, injection of saline, first injection NF-κB inhibitor PDTC or transient receptor potential vanilloid 1 (TRPV1) antagonist Capsazepine or NK1 receptor blockers L703606 and then injection NaHS did not produce significant changes (P > 0.05). NTS contains neurons co-expressing CBS and c-Fos, and the injection of NaHS into the NTS can suppress gastric motility in rats. This effect may be mediated by activating TRPV1 and NK1 receptors via the NF-κB channel.

Gastroprotective effects of Pikad Tri-phol-sa-mut-than herbal remedy on multiple gastric ulcer models in rats

In Thai traditional medicine, Pikad Tri-phol-sa-mut-than has long been used to alleviate gastrointestinal symptoms, renal disease, inflammation-related disorders, and severe malady. This recipe is composed of dried fruits of Morinda citrifolia L., Coriandrum sativum L., and Aegle marmelos (L.) Corrêa. The aim of this study was to assess the anti-gastric ulcer property of the water extract of Pikad Tri-phol-sa-mut-than (TS), using various animal models with different inducers, including restraint water immersion stress, indomethacin, and ethanol/hydrochloric acid (EtOH/HCl). Its mechanisms of anti-gastric ulcer actions were also elucidated using both in vitro and in vivo experiments. When compared with the control groups, the oral pretreatment of TS at the doses of 150, 300 and 600 mg/kg significantly reduced the gastric ulcer formation in all models. It was also found that TS at the dose of 600 mg/kg could increase gastric wall mucus in rats but could not produce the significant reduction of the gastric volume or total acidity of gastric content. Results from hematoxylin and eosin (H&E) and Periodic acid-Schiff (PAS) staining examinations of gastric tissues confirmed that TS visibly reduced gastric mucosal damage, while immunohistochemistry revealed that TS remarkably suppressed the protein expression of Bcl-2-associated X (BAX), a regulator of apoptosis, compared to those of the control group. The DPPH, ABTS, and FRAP assays showed antioxidant effects of TS. All of these findings demonstrated that TS has gastroprotective effects, which may be related to the increase in the gastric wall mucus secretion, not anti-secretory activity, as well as its antioxidant and antiapoptotic activities.

Antiulcer activity and mechanism of action of the hydroethanolic extract of leaves of Terminalia argentea Mart. In different in vivo and in vitro experimental models

Ethnopharmacological relevanceTerminalia argentea Mart. (Combretaceae) is a deciduous tree commonly found in Brazil, Bolivia, and Paraguay. It occurs in all regions of Brazil and is widespread in the Amazon, Cerrado, Pantanal, Atlantic Rain Forest, and Caatinga Biomes. In the traditional medicine of Brazil, people widely use tea or decoction of its leaf materials for treating gastritis, ulcers, wound healing, and inflammation. Aim of the studyThe current study aims to evaluate the gastroprotective and ulcer-healing activities of the hydroethanolic extract of T. argentea leaves (HETa) and investigate the underlying mechanisms of action through in vivo and in vitro experiments. MethodsWe extracted the leaves of T. argentea with a 70% hydroethanolic solution (HETa) and performed phytochemical analysis using high-performance liquid chromatography (HPLC) and electrospray ionization mass spectrometry (ESI-MSn). We researched the antiulcer activity using in vivo and in vitro experiments, administering three doses (2, 10, and 50 mg/kg) and different concentrations of 1, 5, and 20 μg/mL, respectively. We verified the acute antiulcer activity using chemical models (acidified ethanol (EtOH/HCl) and indomethacin (IND)) and physiological models (water-immersion stress (WRS)). To induce chronic ulcers, used acetic acid and treated the animals for seven days. To investigate the mechanism of action, conducted assays of antioxidant activity, measured the dosage of inflammatory cytokines, quantified mucus, treated with inhibitors (IND, L-NAME, glibenclamide, and yohimbine), performed histopathological analysis, and measured gastric acid secretion. Furthermore, we performed in vitro experiments on murine macrophage cell lines (RAW 264-7 cells) to quantify nitrite/nitrate and cytokine production and on V79-4 cells to verify cell proliferation/migration. ResultsWe conducted HPLC and ESI-MSn analyses to obtain a fingerprint of the chemical composition of the HETa, revealing the presence of phenolics (caffeoyl ellagic acid), flavonoids (rutin, quercetin xyloside, quercetin rhamnoside, quercetin glucoside, quercetin galloyl xyloside, quercetin), and tannins (terminalin), respectively. The three doses of HETa reduced acute and chronic ulcers in different models. The mechanism of action involves increasing mucus production and angiogenesis, and it partially involves prostaglandins, nitric oxide, K+ATP channels, and α2-adrenergic receptors. HETa also exhibited antioxidant potential, reducing myeloperoxidase (MPO) activity, and increasing glutathione (GSH) levels. Moreover, it demonstrated anti-inflammatory action by reducing nitrite/nitrate levels and pro-inflammatory cytokine concentrations in vivo, and it increased in vitro proliferation/migration of fibroblasts. ConclusionsThe study shows that HETa presents a potent preventive and curative antiulcer effect in different ulcer models, supporting the popular use of homemade preparations of T. argentea leaves. The preventive and gastric healing ulcer activity of HETa involves multiple targets, including increasing the gastric mucus barrier, antioxidant defenses, and anti-inflammatory effects on gastric mucosa repair. Phytochemical analysis identified the presence of phenolic compounds, flavonoids, and tannins in HETa, and the antiulcer activity may be attributable to the combined effect of these constituents.

Astrocytes in the spinal cord contributed to acute stress-induced gastric damage via the gap junction protein CX43

Rat restraint water-immersion stress (RWIS) is a compound stress of high intensity and is widely used to study the pathological mechanisms of stress gastric ulcers. The spinal cord, as a part of the central nervous system, plays a dominant role in the gastrointestinal tract, but whether the spinal cord is involved in rat restraint water-immersion stress (RWIS)-induced gastric mucosal damage has not been reported. In this study, we examined the expression of spinal astrocytic glial fibrillary acidic protein (GFAP), neuronal c-Fos, connexin 43 (Cx43), and p-ERK1/2 during RWIS by immunohistochemistry and Western blotting. In addition, we intrathecally injected the astrocytic toxin L-a-aminoadipate (L-AA), gap junction blocker carbenoxolone (CBX), and ERK1/2 signaling pathway inhibitor PD98059 to explore the role of astrocytes in the spinal cord in RWIS-induced gastric mucosal damage and its possible mechanism in rats. The results showed that the expression of GFAP, c-Fos, Cx43, and p-ERK1/2 was significantly elevated in the spinal cord after RWIS. Intrathecal injection of both the astrocyte toxin L-AA and the gap junction blocker CBX significantly attenuated RWIS-induced gastric mucosal damage and decreased the activation of astrocytes and neurons induced in the spinal cord. Meanwhile, the ERK1/2 signaling pathway inhibitor PD98059 significantly inhibited gastric mucosal damage, gastric motility and RWIS-induced activation of spinal cord neurons and astrocytes. These results suggest that spinal astrocytes may regulate the RWIS-induced activation of neurons via CX43 gap junctions and play a critical role in RWIS-induced gastric mucosa damage through the ERK1/2 signaling pathway.

Biomarkers in the Rat Hippocampus and Peripheral Blood for an Early Stage of Mental Disorders Induced by Water Immersion Stress

It is difficult to evaluate the pre-symptomatic state of mental disorders and prevent its onset. Since stress could be a trigger of mental disorders, it may be helpful to identify stress-responsive biomarkers (stress markers) for the evaluation of stress levels. We have so far performed omics analyses of the rat brain and peripheral blood after various kinds of stress and have found numerous factors that respond to stress. In this study, we investigated the effects of relatively moderate stress on these factors in the rat to identify stress marker candidates. Adult male Wistar rats underwent water immersion stress for 12 h, 24 h, or 48 h. Stress caused weight loss and elevated serum corticosterone levels, and alterations regarded as anxiety and/or fear-like behaviors. Reverse-transcription PCR and Western blot analyses revealed significant alterations in the expressions of hippocampal genes and proteins by the stress for no longer than 24 h, such as mitogen-activated protein kinase phosphatase 1 (MKP-1), CCAAT/enhancer-binding protein delta (CEBPD), small ubiquitin-like modifier proteins 1/sentrin-specific peptidase 5 (SENP5), matrix metalloproteinase-8 (MMP-8), kinase suppressor of Ras 1 (KSR1), and MKP-1, MMP-8, nerve growth factor receptor (NGFR). Similar alterations were observed in three genes (MKP-1, CEBPD, MMP-8) in the peripheral blood. The present results strongly suggest that these factors may serve as stress markers. The correlation of these factors in the blood and brain may enable the evaluation of stress-induced changes in the brain by blood analysis, which will contribute to preventing the onset of mental disorders.

Gastroprotective and antidepressant-like effect of plum pectin (Prunus domestica L.) under water-immobilization stress in laboratory mice

Stress effects activate the processes of free radical oxidation in the organism, lead to hyper production of reactive radicals and oxidative stress, provoking the development of an inflammatory process in various parts of the gastrointestinal tract. Pectin polysaccharides together with the enzyme components of the endogenous antioxidant system contribute to the elimination of the imbalance between prooxidants and antioxidants in the tissues of stressed animals and have a gastroprotective and antidepressant-like effect. The aim of the research was to evaluate the gastroprotective, antioxidant and antidepressant-like effect of plum pectin orally administered to white laboratory mice before stressful exposure. Material and methods. In the experiment on white BALB/c mice weighing 20-25 g (90 males, 10 in each group), pectin isolated from fresh plum fruits in an artificial gastric environment was used. It was administered orally to mice 24 h before the onset of stress exposure or behavioral activity asessment. 50 animals were subjected to 5 h of water immersion stress. After this corticosterone concentration in blood plasma, and the activity of superoxide dismutase, catalase and glutathione peroxidase in the tissue supernatants of the gastrointestinal tract were determined, and the condition of the gastric mucosa was also assessed. Behavioral activity of experimental mice (n=30) was assessed in the open field and forced swimming tests. Results. The stress effect was accompanied by an increase in plasma corticosterone concentration (more than 3 fold), in the activity of superoxide dismutase, glutathione peroxidase in the tissues of the stomach wall and small intestine (17.9-28.6%) and destructive damage in the gastric mucosa compared with the indices of intact animals. Preliminary oral administration of plum pectin to animals at a dose of 80 mg per 1 kg of body weight helped to reduce the level of corticosterone and the number of stress-induced hemorrhages on the gastric mucosa, normalized the activity of antioxidant enzymes and also decreased the immobility time of mice in the forced swimming test. Preliminary oral administration of plum pectin to animals at a dose of 80 mg per 1 kg of body weight prevented an increase in the activity of antioxidant enzymes, corticosterone in the blood and the development of stress-induced hemorrhages on the gastric mucosa, and reduced the time of immobility of mice in the forced swimming test. Conclusion. Plum fruit pectin pre-administered into mice before stress prevents stress-induced damage in the tissues of the gastrointestinal tract, contributing to an increase in the body's resistance to the stress factor. Plum pectin has an antioxidant, gastroprotective and antidepressant-like effect and can be used as an ingredient in functional foods that reduce the risk of inflammatory diseases of the gastrointestinal tract under stress.

Protective Effects and Mechanisms of Melatonin on Stress Myocardial Injury in Rats.

Prolonged and intense stress can exceed the body's normal self-regulation and limited compensatory and repair capacity, resulting in pathological damage to the body. In this study, we established a rat stress myocardial injury (SMI) model to explore the protective effect of melatonin (MLT) on SMI and its possible mechanisms of action. Adult female Sprague Dawley (SD) rats were randomly divided into 5 groups: blank control group (NC), SMI group, MLT low-dose group, MLT medium-dose group, and MLT high-dose group, and 10 rats in each group were used to establish a SMI model by the water immersion restraint method. We observed the changes in body weight and tail vein glucose of each group. Serum levels of corticosterone (Cort), creatine kinase isoenzyme (CK-MB), and Troponin Ⅰ (Tn-Ⅰ) and activity of lactic acid dehydrogenase were measured by ELISA. Transcriptome sequencing was used to find differentially expressed genes in the control and model groups, and the results were verified by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR). HE staining was used to visualize the pathological changes in the heart tissue of each group, and Western blot was used to study the differences in protein expression in the cardiomyocytes of each group to further corroborate the results. The body weight growth rate of rats in the SMI group was significantly lower than that of the NC group ( P < 0.01), and the body weight growth rate of rats in the MLT high-dose group was significantly higher than that of the SMI group ( P < 0.05) with no significant difference compared with the NC group rats. The mean blood glucose of rats in the SMI group was significantly higher compared with the NC group ( P < 0.001), while the mean blood glucose of rats in the MLT administration groups was dose-dependently reduced compared with the SMI group. By RNA-seq and bioinformatics tools such as KEGG and Gene ontology, we found that the circadian clock-related genes Ciart , Arnt1 , Per1 , and Dbp were significantly downregulated in the SMI group during water immersion stress, and differentially expressed genes were enriched in the p38MAPK signaling pathway and p53 signaling pathway. Moreover, genes related to inflammation and apoptosis were differentially expressed. ELISA results showed that Cort, CK-MB, and Tn-Ⅰ levels were significantly higher in the SMI group compared with the NC group ( P < 0.01) and melatonin reduced the levels of Cort, CK-MB, and Tn-Ⅰ and decreased lactic acid dehydrogenase activity in rat serum. HE staining results showed that melatonin could attenuate stress-generated myocardial injury. Western blot showed that melatonin reduced the expression of p38MAPK, p53, Bax, and caspase-3 and increased the expression of Bcl-2 protein in rat heart. Melatonin can inhibit myocardial injury caused by water immersion, and its mechanism of action may be related to the regulation of the expression of circadian clock genes such as Ciart , Arnt1 , Per1 , and Dbp ; the inhibition of the expression of proapoptotic proteins such as p38MAPK, p53, Bax, and caspase-3; and the increase of the expression of Bcl-2 antiapoptotic protein.

Stress-Relieving Effects of Sesame Oil Aroma and Identification of the Active Components.

(1) Sesame oil aroma has stress-relieving properties, but there is little information on its effective use and active ingredients. (2) Methods: ICR male mice were housed under water-immersion stress for 24 h. Then, the scent of sesame oil or a typical ingredient was inhaled to the stress groups for 30, 60, or 90 min. We investigated the effects of sesame oil aroma on mice behavior and the expression of the dual specificity phosphatase 1 (DUSP1) gene, a candidate stress marker gene in the brain. (3) Results: In an elevated plus-maze test, the rate of entering into the open arm of a maze and the staying time were increased to a maximum after 60 min of inhalation, but these effects decreased 90 min after inhalation. As for the single component, anxiolytic effects were observed in the 2,5-dimethylpyrazine and 2-methoxy phenol group, but the effect was weakened in the furfuryl mercaptan group. The expression levels of DUSP1 in the hippocampus and striatum were significantly decreased in 2,5-dimethylpyrazine and 2-methoxy phenol groups. (4) Conclusions: We clarified the active ingredients and optimal concentrations of sesame oil for its sedative effect. In particular, 2,5-dimethylpyrazine and 2-methoxy phenol significantly suppressed the stress-induced changes in the expression of DUSP1, which are strong anti-stress agents. Our results suggest that these molecules may be powerful anti-stress agents.

Stress upregulates 2-arachidonoylglycerol levels in the hypothalamus, midbrain, and hindbrain, and it is sustained by green nut oil supplementation in SAMP8 mice revealed by DESI-MSI

The endocannabinoid 2-arachidonoylglycerol (2AG) is an important modulator of stress responses. Its level in the brain increases in response to stress, but region-specific effects of stress on brain 2AG are not well known yet. Moreover, green nut oil (GNO), oil extracted from the seeds of Plukenetia volubilis has several health benefits, but its effects on brain 2AG levels are unknown. Therefore, we conducted this study to explore the effects of stress and GNO supplementation on 2AG levels in specific brain regions of senescence-accelerated mouse prone 8 (SAMP8). In this study, desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) revealed that water-immersion stress for three days significantly increased 2AG levels in several brain regions of SAMP8 mice, including the hypothalamus, midbrain, and hindbrain. No significant change was observed in the relative abundance of brain 2AG in stress given SAMP8 mice after eighteen days of removing stress load compared to control SAMP8 mice. GNO supplementation also increased brain 2AG in SAMP8 mice without stress load. Additionally, GNO supplementation sustained the increased brain 2AG levels in stress given SAMP8 mice after eighteen days of removing stress load. Among all brain regions, a relatively higher accumulation of 2AG was noted in the hypothalamus, midbrain, and hindbrain of GNO-fed SAMP8. Our data explored the potentiality of GNO supplementation to improve brain 2AG levels which might be used to treat anxiety and depressive behaviors.

Studies on Mechanism of Preventive Effect of Fermentation Product of Calvatia lilacina on Water-Immersion Stress Induced Gastric Ulcers in Mice

Studies on Mechanism of Preventive Effect of Fermentation Product of Calvatia lilacina on Water-Immersion Stress Induced Gastric Ulcers in Mice

Enhancement of the RhoA/Rho kinase pathway is associated with stress-related erectile dysfunction in a restraint water immersion stress model.

Stress is a risk factor for erectile dysfunction (ED); however, the pathology of stress‐induced ED remains unclear. Accordingly, in this study, we investigated the mechanisms of stress‐induced ED using a rat model. Ten‐week‐old male Wistar/ST rats were maintained in a cage filled with water to a height of 2 cm (stress group) or a normal cage (control group). We found that water immersion stress significantly enhanced the contractile response to noradrenaline in the corpus cavernosum (CC) (p < 0.05). Moreover, stress significantly decreased erectile function, as assessed by changes in intracavernous pressure (p < 0.01). In addition, Rho kinase‐1 (ROCK‐1) protein expression was significantly upregulated under stress conditions (p < 0.05), and phosphorylated myosin light chain (phospho‐MLC) levels, contribute to smooth muscle contraction, were also upregulated (p < 0.01). Treatment with fasudil hydrochloride, a Rho kinase inhibitor, for 5 days significantly improved erectile function (p < 0.01) and normalized ROCK‐1 and phospho‐MLC levels (p < 0.01). Thus, the RhoA/Rho kinase pathway may be associated with stress‐induced ED via contraction of CC. Stress also decreased the smooth muscle/collagen ratio of CC (p < 0.01), and fasudil treatment did not alleviate these effects (p = 0.50). These findings suggested that penile fibrosis gradually progressed under stress conditions and that fibrosis may be independent of the RhoA/Rho kinase pathway, implying that longer exposure to stress may promote ED. We conclude that stress‐induced ED was caused by contraction of CC mediated by the RhoA/Rho kinase pathway.

The Protective Effect of Dapsone Against Ethanol, Stress, and Indomethacin-Induced Gastric Erosion in Rats

Several factors contribute to the development of gastric erosions, including corticosteroids and nonsteroidal anti-inflammatory drugs (NSAIDs), alcohol, and stress. These factors can cause or worsen gastrointestinal ulcers by activating inflammatory pathways or by altering gastric mucosal blood flow. Dapsone is an antimicrobial compound with anti-inflammatory properties. The aim of this study was to evaluate the protective effects of dapsone against gastric erosions induced by alcohol, stress, or indomethacin. Gastric damage was induced in male rats in three different experimental models: ethanol (5 ml/kg, p.o.)-, water-immersion stress-, and indomethacin (30 mg/kg, p.o.)- induced ulcer. Rats in each of these three experimental models were divided into five groups: Normal group, 2. Control group (gastric damage+vehicle), 3. Gastric damage+dapsone 1 mg/kg, 4. Gastric damage+dapsone 3 mg/kg, 5. Gastric damage+dapsone 10 mg/kg. In this study, the J- score ulcer index and histopathological assessment were performed. In addition, inflammatory cytokines levels, NF-κB expression, and MPO activity were determined. Dapsone reduced the tissue injuries and erosion area in all three experimental groups compared to the control group. In addition, serum levels of inflammatory cytokines, TNF-alpha, and IL-1β were reduced in the dapsone treatment groups. The expression of NF-κB and tissue concentration of myeloperoxidase (a marker of neutrophil activation) was also reduced in rats given dapsone. To conclude, dapsone exhibits significant protective effects against the development of experimental gastric erosions in rats, and these effects seem to be related to its anti-inflammatory and antioxidant properties.

Acupuncture Treatment for Social Defeat Stress.

Depression is a mood disorder characterized by disordered affect, thoughts, cognition, and behavior. Antidepressant therapy is often the primary treatment for depression. However, antidepressant therapy may cause unwanted side effects, and its effects are slow. Therefore, some patients are seeking alternative treatments for depression, such as acupuncture. However, there are many unclear points regarding the mechanism of the effect of acupuncture on depression. In recent years, we have reported that acupuncture improves the symptoms of mild depression induced by water-immersion stress in a rat model and depression induced by forced swimming in a mouse model. In this study, we examined the effect of acupuncture on the symptoms of social defeat stress (SDS)-induced depression in mice that most closely resemble human symptoms. In this study, we investigated the preventive and therapeutic effects of acupuncture as part of GV20 “Bai-Hui” and Ex-HN3 “Yintang” on model mice with depression induced by SDS. To examine the mechanism of the preventive and therapeutic effects of acupuncture on depression model mice, we examined the expression of neurotrophic factors in the brains of SDS mice. Two weeks of simultaneous acupuncture stimulation as part of GV20 and Ex-HN3 restored SDS-reduced brain-derived neurotrophic factor (BDNF), neurotrophin (NT)-3, and NT-4/5 expression, which was not observed with antidepressants. In contrast, acupuncture stimulation suppressed nerve growth factor (NGF) expression induced by SDS. These results suggest that acupuncture treatment could be effective in correcting the imbalance in the expression of neurotrophic factors. Furthermore, the effects of acupuncture on the expression of neurotrophic factors appear earlier than those of antidepressants, suggesting that it may be a useful treatment for depression.

Gastroprotective Activities of Ethanol Extract of Black Rice Bran (Oryza sativa L.) in Rats.

Black rice is a type of rice in the Oryza sativa L. species. There are numerous reports regarding the pharmacological actions of black rice bran, but scientific evidence on its gastroprotection is limited. This study aimed to evaluate the gastroprotective activities of black rice bran ethanol extract (BRB) from the Thai black rice variety Hom Nil (O. sativa L. indica) as well as its mechanisms of action, acute oral toxicity in rats, and phytochemical screening. Rat models of gastric ulcers induced by acidified ethanol, indomethacin, and restraint water immersion stress were used. After pretreatment with 200, 400, and 800 mg/kg of BRB in test groups, BRB at 800 mg/kg significantly inhibited the formation of gastric ulcers in all gastric ulcer models, and this inhibition seemed to be dose dependent in an indomethacin-induced gastric ulcer model. BRB could not normalize the amount of gastric wall mucus, reduce gastric volume and total acidity, or increase gastric pH. Although BRB could not increase NO levels in gastric tissue, the tissue MDA levels could be normalized with DPPH radical scavenging activity. These results confirm the gastroprotective activities of BRB with a possible mechanism of action via antioxidant activity. The major phytochemical components of BRB comprise carotenoid derivatives with the presence of phenolic compounds. These components may be responsible for the gastroprotective activities of BRB. The 2000 mg/kg dose of oral BRB showed no acute toxicity in rats and confirmed, in part, the safe uses of BRB.

Neurons and Astrocytes in Ventrolateral Periaqueductal Gray Contribute to Restraint Water Immersion Stress-Induced Gastric Mucosal Damage via the ERK1/2 Signaling Pathway

BackgroundThe restraint water immersion stress (RWIS) model includes both psychological and physical stimulation, which may lead to gastrointestinal disorders and cause gastric mucosal damage. The ventrolateral periaqueductal gray (VLPAG) contributes to gastrointestinal function, but whether it is involved in RWIS-induced gastric mucosal damage has not yet been reported.MethodsThe expression of glial fibrillary acidic protein, neuronal c-Fos, and phosphorylated extracellular signal regulated kinase 1/2 in the VLPAG after RWIS was assessed using western blotting and immunocytochemical staining methods. Lateral ventricle injection of astrocytic toxin L-a-aminoadipate and treatment with extracellular signal-regulated kinase (ERK)1/2 signaling pathway inhibitor PD98059 were further used to study protein expression and distribution in the VLPAG after RWIS.ResultsThe expression of c-Fos, glial fibrillary acidic protein, and phosphorylated extracellular signal regulated kinase 1/2 in the VLPAG significantly increased following RWIS and peaked at 1 hour after RWIS. Lateral ventricle injection of the astrocytic toxin L-a-aminoadipate significantly alleviated gastric mucosal injury and decreased the activation of neurons and astrocytes. Treatment with the ERK1/2 signaling pathway inhibitor PD98059 obviously suppressed gastric mucosal damage as well as the RWIS-induced activation of neurons and astrocytes in the VLPAG.ConclusionsThese results suggested that activation of VLPAG neurons and astrocytes induced by RWIS through the ERK1/2 signaling pathway may play a critical role in RWIS-induced gastric mucosa damage.

Water immersion tolerance by larval instars of stable fly, Stomoxys calcitrans, L1758 (Diptera: Muscidae) impairs the fitness performance of their subsequent stages

BackgroundIn holometabolous insects, environmental factors experienced in pre-imaginal life stages affect the life-history traits within that stage and can also influence subsequent life stages. Here, I assessed tolerance to water immersion by the larval instars of the stable fly, Stomoxys calcitrans L. (Diptera: Muscidae) and its impact on the life-history traits of their subsequent life stages.ResultsAfter submerging the three larval instars of S. calcitrans in distilled water, I found that the first instar larvae remained active for longer as compared to the second and third instar larvae. Also, the first instar larvae took a longer period to recover from the stress-induced immobility when removed from the water and returned to ambient temperature. When I followed the development of individuals of each larval instar that survived from water immersion, I found that their developmental time, weight, pupation percentage, adult emergence percentage and adult weight were negatively affected by this stressor. However, the weight of S. calcitrans adults developed from immersed first larval instar individuals was not affected by water immersion whereas their counterparts developed from immersed second and third larval instars had lower body weight. This suggests that in S. calcitrans, water immersion stress at the earlier stage is less detrimental than that experienced at late stages.ConclusionThis study provides a comparative overview of the fitness consequences associated with water immersion stress during S. calcitrans larval ontogeny. The results prove that the fitness shift induced by water immersion in S. calcitrans is stage-specific. My results illustrate the importance of considering each larval instar when assessing the impact of environmental factors on holometabolous insect performance as these may be decoupled by metamorphosis.

Anti-ulcerogenic effect of methanolic extract of Elaeagnus conferta Roxb. seeds in Wistar rats

Ethnopharmacological relevanceElaeagnus conferta Roxb. (Elaeagnaceae) is a subtropical shrub mainly native to India, Vietnam, Malaysia and South China, whose various parts are used for treatment of diabetes, gastric ulcers, pain, oxidative stress and pulmonary disorders. Though the other parts of the plant have been reported for their ethnic use i.e. fruits as astringent locally and for cancer systemically, leaves for body pain and flowers for pain in chest and the seeds are mentioned as edible, there is no report per se on the medicinal use of seeds. Based on the fact that seeds of closely resembling species i.e. Elaeagnus rhamnoides has demonstrated significant anti-gastroulcerative property, the probability of the seeds of E. conferta possessing similar activity seemed quite significant. Aim of the studyPhytochemical investigation and assessment of pharmacological mechanism(s) involved in anti-ulcer effect of methanolic extract of the seeds of E. conferta. Materials and methodsBioactive phytoconstituents were isolated by column chromatography. These were identified by spectroscopic techniques including infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) and mass spectrometry. Methanolic extract (MEC) of the seeds was prepared by cold maceration and its anti-ulcerogenic potential was evaluated using indomethacin (50 mg/kg) and water immersion stress models in male rats. The animals were pre-treated with different doses of MEC (400 and 800 mg/kg) and the therapeutic effect was compared with standard drug i.e. ranitidine (RANT; 50 mg/kg). The ameliorative effects of MEC were investigated on gastric juice pH, total acidity, free acidity and ulcer index. The assays of malionaldehyde (MDA), catalase (CAT), superoxide dismutase (SOD), glutathione (GSH) and pro-inflammatory cytokines i.e. interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were carried out to find out the possible mechanism(s) of protection. Further, histopathological changes were also studied. ResultsChromatography studies and further confirmation by spectroscopic techniques revealed the presence of four different compounds in MEC i.e oleic acid (1), stearic acid (2), ascorbic acid (3) and quercetin (4). MEC exhibited anti-ulcerogenic effect in dose dependent manner which may be attributed to suppression of pro-inflammatory cytokines (IL-6, TNF-α) and MDA (112.7%), and up-regulation of protective factors such as CAT (90.48%), SOD (92.77%) and GSH (90.01%). Ulcer inhibition, reduction in total and free acidity and increase in gastric juice pH were observed in MEC treated rats as compared to disease control animals. Histopathological findings confirmed decreased cell infiltration, less epithelial cell damage and regeneration of gastric mucosa in dose dependent manner. ConclusionsThe anti-ulcer effect of MEC may be attributed to its ability to scavenge free radicals and anti-inflammatory property via suppression of TNF-α and IL-6, thus offers a complete and holistic approach for management of peptic ulcer.

Effect of acupuncture on intestinal flora and TLR4 in brain and intestinal tissues in rats with stress gastric ulcer

To observe the effect of acupuncture at "Guanyuan" (CV 4) and "Xiajuxu" (ST 39) on intestinal flora and Toll-like receptors-4 (TLR4) in brain and intestinal tissue in rats with stress gastric ulcer (SGU), and to explore the possible mechanism of acupuncture for SGU. Thirty-one male SD rats were randomly divided into a blank group (n=7), a model group (n=8), an acupuncture group (n=8) and a drug group (n=8). The rats in the model group, acupuncture group and drug group were treated with modified restraint plus water-immersion stress method to establish SGU model. After modeling, the rats in the acupuncture group were treated with acupuncture at "Guanyuan" (CV 4) and "Xiajuxu" (ST 39), 20 min each time, and the needles were twirled for 30 s every 5 min. The rats in the drug group were treated with intragastric administration of 2 mL omeprazole enteric-coated tablets (20 mg/mL). Both the treatments were given once a day for 5 days. After the intervention, the gastric mucosal damage index was calculated by Guth method; the morphological changes of gastric mucosa were observed by HE staining; the diversity of intestinal flora was detected by 16S rDNA high-throughput sequencing; TLR4 contents in brain and intestinal tissues were determined by ELISA. Compared with the blank group, the gastric mucosal damage index was significantly increased in the model group (P<0.01); the morphological changes of gastric mucosa were obvious; the Observed Species index and Shannon index of α diversity index of intestinal flora were decreased (P<0.05); the β diversity showed that the spatial distance between the model group and the blank group was far; the TLR4 contents in the brain and intestinal tissue were increased (P<0.05, P<0.01). Compared with the model group, the gastric mucosal damage index was decreased in the acupuncture group and the drug group (P<0.05); the morphology of gastric mucosa was improved; the Observed Species index and Shannon index of α diversity index of intestinal flora in the acupuncture group was increased (P<0.05), and the Shannon index in the drug group was increased (P<0.05); the β diversity showed that the spatial distance between the acupuncture group and the blank group was close; the TLR4 contents in the brain and intestinal tissues of the acupuncture group were decreased (P<0.01). Compared with the drug group, the contents of TLR4 in the intestinal tissue of the acupuncture group were decreased (P<0.05). Acupuncture at "Guanyuan" (CV 4) and "Xiajuxu" (ST 39) could alleviate SGU in rats, and its mechanism may be related to increasing the diversity of intestinal flora, promoting the disorder of intestinal flora to normal, and reducing the overexpression of TLR4 in brain and intestinal tissues.