Stimulation of gastric ulcer healing by heat shock protein 70

In-depth molecular assessment of Hedera helix's L. α - Hederin & Hederacoside C as a gastroprotective & a possible safe Omeprazole phyto-alternative in ethanol-induced gastric ulcer mice model

Hedera helix L. is among the most popular over-the-counter formulations for effectively alleviating respiratory disorders in adults & children due to its unique active constituents such as α - Hederin & Hederacoside C. Even though its respiratory pharmacological activity is thoroughly researched, its other pharmacological activities remain relatively unexplored. Alcoholism is a Western cultural habit that is associated with various side effects, including peptic ulcer disease (PUD) & drug interaction. The PUD is commonly & recurrently presented clinically, increasing the load on healthcare systems. PUD not only negatively affects the quality of life but is also associated with serious complications such as bleeding, penetration, perforation, pyloric stenosis, & gastric cancer. Alcohol interaction with drugs could either lead to therapeutic failure, accumulation of drug-toxic metabolites, or disturbance of the alcohol detoxification pathway, putting the treatment of alcoholism-induced PUD with a drug-interacting medication such as Omeprazole under the limelight. In line with that, finding plant-derived molecules with the potency of Omeprazole but without its associated side effects & drug-interacting property is a desperate clinical need. In this regard, we aimed to investigate the gastroprotective effect, potency, & molecular mechanism of α - Hederin & Hederacoside C pretreatment against ethanol-induced gastric ulcer in mice model. These compounds were tested in two upgrading doses (50 mg/kg & 75 mg/kg) compared to negative, positive, & Omeprazole groups. Our study revealed that daily oral administration of α - Hederin or Hederacoside C protected the stomach against ethanol-induced gastric ulcers in a dose-dependent manner. The potency of high doses of both compounds was comparable to Omeprazole. Their effectiveness was related to their ability to set the activated invasive forces, including CYP1A2, neutrophils, MDA, leptin, TNF-α, IL-6, IL-12, & NF-κB-p65 & to amplify the intrinsic defensive forces, including COX-2, PGE-2, CAT, & SOD. These intertwined actions were reflected in maintaining vibrant stomach architecture, such as mucosal layer re-epithelization, gland reconstruction, & restoring tunica muscularis normal thickness. Moreover, they limited the exaggeration of the repairing system, including HSP-70, VEGF, & Annexin-1, where their forge was positively correlated with damage depth. Therefore, we compendiously deduced that herbal-based medicine could face the constraints of synthesized medicine satisfactorily without their culminating side effects.

Association between wet-bulb globe temperature with peptic ulcer disease in different geographic regions in a large Taiwanese population study

BACKGROUND

Peptic ulcer disease (PUD) is a common and important cause of morbidity worldwide, with a large impact on healthcare costs. Little research has been conducted on the association between wet-bulb globe temperature (WBGT) and PUD. The aim of this study was to explore this association among different geographical regions of Taiwan in a large sample of participants.

METHODS

This is a cross-sectional study. The study participants (n = 120,424) were enrolled from the Taiwan Biobank (TWB) and resided across northern, central, southern and eastern Taiwan. Self-reported questionnaires were used to ascertain the occurrence of PUD. Average WBGT values were recorded during working hours (8:00 AM to 5:00 PM) and the noon period (11:00 AM to 2:00 PM) for each participant at 1, 3, and 5 years before the TWB survey year. The association between WBGT and PUD was examined with logistic regression analysis.

RESULTS

The 1-year and 5-year noon WBGT values per 1℃ increase were significantly associated with a low prevalence of PUD in northern Taiwan (odds ratio [OR], 0.960, 95% confidence interval [CI], 0.925-0.955; OR, 0.962, 95% CI, 0.929-0.997; respectively). In contrast, there were no significant associations between WBGT and PUD in central Taiwan. In southern Taiwan, the 1-, 3-, and 5-year WBGT values per 1℃ increase during the noon period (OR, 0.875, 95% CI, 0.873-0.909; OR, 0.860, 95% CI, 0.825-0.896; OR, 0.848, 95% CI, 0.812-0.885; respectively) and working period (OR, 0.852, 95% CI, 0.825-0.880; OR, 0.845, 95% CI, 0.816-0.876; OR, 0.832, 95% CI, 0.0.801-0.863; respectively) were significantly associated with a low prevalence of PUD. However, in eastern Taiwan, the 1-, 3-, and 5-year WBGT values per 1℃ increase during the noon period (OR, 1.074, 95% CI, 1.022-1.127; OR, 1.058, 95% CI, 1.013-1.104; OR, 1.058, 95% CI, 1.013-1.105; respectively), and the 3- and 5-year WBGT values per 1℃ increase during the working period were significantly associated with a high prevalence of PUD (OR, 1.049, 95% CI, 1.003-1.097; OR, 1.047, 95% CI, 1.001-1.095; respectively). Based on nonlinear trend analysis, WBGT was categorized into three groups for the noon period or work period, and the results were similar to and generally consistent with those in linear models.

CONCLUSION

The associations between WBGT and PUD differed across the geographical regions of Taiwan. In northern and southern Taiwan, increases in average WBGT values were significantly associated with a low prevalence of PUD. In addition, this relationship was much stronger in southern Taiwan than in northern Taiwan. Of note, there was a reverse relationship between WBGT and PUD during the noon and working periods in eastern Taiwan. Further studies are needed to elucidate the effects of WBGT on PUD.

The Role of Triterpenoids in Gastric Ulcer: Mechanisms and Therapeutic Potentials

Gastric ulcer (GU) is a prevalent gastrointestinal disorder impacting millions worldwide, with complex pathogenic mechanisms that may progress to severe illnesses. Conventional therapies relying on anti-secretory agents and antibiotics are constrained by drug abuse and increased bacterial resistance, highlighting the urgent need for safer therapeutic alternatives. Natural medicinal compounds, particularly triterpenoids derived from plants and herbs, have gained significant attention in recent years due to their favorable efficacy and reduced toxicity profiles. Emerging evidence indicates that triterpenoids exhibit potent anti-ulcer properties across various experimental models, modulating key pathways involved in inflammation, oxidative stress, apoptosis, and mucosal protection. Integrating current knowledge of these bioactive compounds facilitates the development of natural triterpenoids, addresses challenges in their clinical translation, deepens mechanistic understanding of GU pathogenesis, and drives innovation of therapeutic strategies for GU. This review comprehensively evaluates the progress of research on triterpenoids in GU treatment since 2000, discussing their biological sources, structural characteristics, pharmacological activities, and mechanisms of action, the animal models employed in the studies, current limitations, and the challenges associated with their clinical application.

Unlocking the potential of Radix Astragali and its active ingredients in gastric ulcer therapy

We studied the protective effects of Radix Astragali (RA) on gastric ulcer (GU). A literature search was conducted using databases from Web of Science, PubMed, Springer, ScienceDirect, Science Direct Chinese National Knowledge Infrastructure (CNKI), and Wanfang. The inclusion criteria for this study were limited to reports on the effects of RA, AS-IV, cycloastragenol, astragalus polysaccharide (APS), and astragalosides (AST) in the treatment of gastric ulcers. Any studies involving gastric lesions that were precancerous or cancerous were eliminated. The search period was from database inception through June 2024. The results suggested RA hold promiseas potential novel therapeutics for the therapy of GU.

Overexpression of HSP27 accelerates stress-induced gastric ulcer healing via the CXCL12/CXCR4 axis

Chronic stress often triggers gastrointestinal complications, including gastric injury and ulcers. Understanding the role of heat shock protein 27 (HSP27) in stress-induced gastric ulcers could unveil novel therapeutic targets. Here, we established a stress-induced gastric ulcer rat model using water immersion restraint stress and administered adenovirus-packaged HSP27 overexpression vector. Gastric ulcer severity was scored, and mucosal changes were assessed. Gastric epithelial and endothelial cells were treated with lipopolysaccharide and transfected with HSP27 overexpression vectors to evaluate cell viability, migration and angiogenesis. Expression levels of HSP27, C-X-C motif chemokine ligand 12 (CXCL12) and C-X-C motif chemokine receptor 4 (CXCR4) were measured in tissues and cells. HSP27 expression was initially low during stress-induced gastric ulceration but increased during ulcer healing. HSP27 overexpression accelerated ulcer healing in rats, promoting gastric epithelial cell proliferation and migration and gastric endothelial cell angiogenesis through the CXCL12/CXCR4 axis. Inhibitor IT1t reversed the effects of HSP27 overexpression on cell proliferation, migration and angiogenesis. In summary, HSP27 overexpression facilitated ulcer healing, which was partially mediated by the CXCL12/CXCR4 axis.

Heat shock protein 70 is involved in polaprezinc driven cell protection against Helicobacter pylori-induced injury

Polaprezinc (PZ) plays a role in the protection of gastric mucosa and inhibiting Helicobacter pylori (H. pylori) growth in vitro. The objective of this study was to determine the protective effects of PZ on human gastric epithelial cells (GES-1) against H. pylori-induced damage, while also examining heat shock protein 70 (HSP70) as a potential underlying factor in this protection. Our findings revealed that PZ exerted bactericidal effects against H. pylori strains. We also observed that PZ mitigated the H. pylori-induced damage to GES-1 cells by increasing cell viability, reducing LDH release, and decreasing the secretion of pro-inflammatory factors such as MCP-1 and IL-6. Co-culturing PZ with GES-1 cells significantly up-regulated the GES-1 HSP70 expression in both a time and dose-dependent manner. Pre-incubating (for 12 h) or co-culturing (for 24 h) GES-1 cells with PZ reversed the down-regulation of HSP70 in GES-1 cells caused by H. pylori infection. However, when quercetin was used to inhibit the up-regulation of HSP70 in GES-1 cells, the protective effect of PZ on GES-1 cells was significantly reduced. Based on the results of this study, PZ exhibits a protective role on GES-1 cells against H. pylori injury, as well as a direct bactericidal effect on H. pylori. HSP70 is involved in the PZ-driven host cell protection against H. pylori injury. These findings provide insight into alternative strategies for H. pylori treatment.

[Pharmacokinetics and pharmacodynamics of rebamipide. New possibilities of therapy: A review]

The MedLine database contains 570 publications, including 71 randomized clinical trials and 6 meta-analyses on the rebamipide molecule in 2022. Indications for the use of rebamipide are gastric ulcer, chronic gastritis with hyperacidityin the acute stage, erosive gastritis, prevention of damage to the gastrointestinal mucosa while taking non-steroidal anti-inflammatory drugs, eradication of Helicobacter pylori. Currently trials are studying the efficacy and safety of the drug in gouty and rheumatoid arthritis, osteoarthritis, Sjögren's syndrome, bronchial asthma, vitiligo, atherosclerosis, diseases of the kidneys and liver; using in traumatology to accelerate bone regeneration; in ophthalmology to improve the regeneration of corneal epithelium; in oncology to reduce inflammatory changes in the oral mucosa after chemoradiotherapy. The review article is about the main pharmacokinetic and pharmacodynamic characteristics of rebamipide. A detailed understanding of pharmacodynamics and pharmacokinetics allows for individual selection of therapy based on the characteristics of the patient's body - gender, age, comorbidities; choose the optimal route of administration and dosing regimen; predict adverse effects and drug interactions; be determined with new clinical indications.

Investigation on the Effects and Mechanisms of Alkaline Natural Mineral Water and Distilled Water on Ethanol-Induced Gastric Ulcers In Vivo and In Vitro

Studies have proven that alkaline water has a protective effect on gastric diseases. However, the underlying mechanism is not clear. Moreover, in some countries, especially in China, purified water (distilled water) is also an important form of drinking water, while its protective effect on gastric diseases is still unknown. This study aimed to compare the effects of distilled water (pH = 5.6 ± 0.3) and alkaline natural mineral water (pH = 9.3 ± 0.6) on ethanol-induced gastric ulcers in mice and to further clarify the underlying mechanisms. Pepsin activity, prostaglandin E-2 (PGE2) and heat shock protein 70 (HSP70), superoxide dismutase (SOD), reduced glutathione (GSH), and malondialdehyde (MDA), as well as the oxidative stress pathway related proteins such as nuclear factor erythroid-2 related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NADH quinone oxidoreductase 1 (NQO1) were measured. After alkaline natural mineral water treatment, the levels of PGE2 and HSP70 were significantly increased (p < 0.05). Antioxidant indexes (SOD, GSH, and MDA) and Western blot results (Nrf2, HO-1, and NQO1) showed that alkaline natural mineral water did not alleviate gastric ulcers by improving oxidative stress. Pepsin activity assay displayed that the pepsin activity was significantly declined after alkaline natural mineral water treatment compared with the distilled water treatment (p < 0.05). This study indicated that alkaline natural mineral water may alleviate the ethanol-induced gastric ulcers in mice by inhibiting the pepsin activity and increasing the levels of PGE2 and HSP70.

Gastroprotective effect and mechanisms of Chinese sumac fruits (Rhus chinensis Mill.) on ethanol-induced gastric ulcers in mice

This paper aimed to study the effect of the phenol-rich fraction from Chinese sumac fruits on ethanol-induced gastric ulcers in mice and to further elucidate the potential mechanisms. The results showed that the phenol-rich fraction of the fruits significantly decreased the ulcer index, restored the levels of prostaglandin E-2, heat shock protein 70, glutathione and superoxide dismutase, and reduced the malondialdehyde content. Further analyses revealed that the fraction significantly alleviated the gastric oxidative stress by upregulating the Nrf2 protein pathway to increase the HO-1 and NQO1 expression levels, suppressed the inflammation by reducing the expression levels of p-NF-κB and p-IκBα and inhibited the secretion of tumor necrosis factor-α, interleukin-1β, and interleukin-6. In addition, the fraction remarkably prevented gastric mucous cell apoptosis by upregulating Bcl-2 and downregulating Bax and cleaved caspase3. This experiment clarified for the first time that the phenol-rich fraction from Chinese sumac fruits can prevent ethanol-induced gastric ulcers in mice by inhibiting the oxidative stress, inflammatory response and cell apoptosis. The results obtained from the current work indicated that the phenol-rich fraction from Chinese sumac fruits could be applied as a kind of natural resource for producing new functional foods to prevent and/or improve gastric ulcers induced by ethanol.

In vivo acute toxicity and anti-gastric evaluation of a novel dichloro Schiff base: Bax and HSP70 alteration

Chlorine is shown to possess anti-gastric ulcer activity, since it can inactivate Helicobacter pylori, which is regarded as one of the most common risk factors for causing gastric problems. In the current study, the gastroprotective property of a novel dichloro-substituted Schiff base complex, 2, 2'- [-1, 2-cyclohexanediylbis(nitriloethylidyne)] bis(4-chlorophenol) (CNCP), against alcohol-induced gastric lesion in SD rats was assessed. SD rats were divided into four groups, i.e. normal, ulcer control, testing, and reference groups. Ulcer area, gastric wall mucus, and also gastric acidity of the animal stomachs were measured. In addition, antioxidant activity of CNCP was evaluated and its safe dose was identified. Immunohistochemistry staining was also carried to evaluate two important proteins, i.e. Bcl2-associated X protein (Bax) and heat shock protein 70 (HSP70). Moreover, the activities of super oxide dismutase and catalase, as well as the levels of prostaglandin E2 (PGE2) and malondialdehyde (MDA) were also measured. Antioxidant activity of CNCP was approved via the aforementioned experiments. Histological evaluations showed that the compound possesses stomach epithelial defense activity. Additionally, periodic acid-Schiff staining exhibited over-expression of HSP70 and down-expression of Bax protein in the CNCP-treated rats. Moreover, CNCP caused deceased MDA level and elevated PGE2 level, and at the same time increased the activities of the two enzymes.

Therapeutic effects of hydro-alcoholic extract of Achillea wilhelmsii C. Koch on indomethacin-induced gastric ulcer in rats: a proteomic and metabolomic approach

BACKGROUND

Gastric ulcer is one of the most prevalent diseases worldwide. In Iranian folk medicine, Achillea wilhelmsii (AW) is used as a treatment for gastric ulcer. Previous reports also mentioned Antiulcerogenic properties for this herbal plant. This study investigated the therapeutic effects of Achillea wilhelmsii C. Koch extract on indomethacin-induced gastric lesion in rats, from both proteomic and metabolomic perspectives.

METHODS

The rats were divided into 4 groups. Gastric ulceration was induced by a single dose of indomethacin (45 mg/kg) by oral gavage. An amount of 800 mg/kg of AW extract was administered orally. Serum and tissue samples were collected for further investigations. The metabolomic study was performed by 1H-NMR CPMG spectrometry. Proteomic analysis was also executed by using two dimensional gel electrophoresis (2DE) followed by liquid chromatography coupled to tandem mass spectrometry (LC-ESI/MS/MS). Real time PCR was used to confirm some of the genes.

RESULTS

The macroscopic and microscopic investigations confirmed the effectiveness of the AW extract. There was a panel of metabolites which showed alteration during gastric lesion development. The levels of some of these metabolite reversed nearly to their control values after the administration of AW extract. There were also changes in the levels of some proteins including Alb, Fabp5, Hspb1, Tagln, Lgals7, Csta and Myl9 which were reversed after AW administration.

CONCLUSIONS

Our findings suggested that Achillea wilhelmsii C. Koch extract could be a potential therapy to be used for indomethacin-induced gastric lesion treatment in the future. However, further investigations are needed to confirm the results.

Heat shock protein 90 and inflammatory activity in newly onset Crohn's disease

OBJECTIVE

The aim of the study was to investigate whether heat shock protein (HSP)90α plasma concentrations were associated with disease activity in patients with Crohn's disease.

MATERIALS AND METHODS

This cross-sectional study included 53 patients who were newly diagnosed with Crohn's disease. Demographic data and disease distribution were recorded, and disease activity was rated using the Simple Endoscopic Score for Crohn's Disease (SES-CD) and the Harvey Bradshaw Index (HBI). Faecal calprotectin and plasma concentrations of CRP and HSP90α were measured.

RESULTS

The median SES-CD was 7, and the median HSP90α level was 17.2 ng/mL. The HSP90α level was significantly correlated with SES-CD, CRP, and faecal calprotectin, but not with HBI. Linear regression analysis revealed that HSP90α was significantly associated with SES-CD (r² = 0.27, p < .001) and with CRP (r² = 0.18, p = .002). HSP90α concentrations were significantly higher in the 10 patients with the highest SES-CD scores compared to the 10 patients with the lowest SES-CD scores.

CONCLUSIONS

Objective measures of disease activity and inflammation in Crohn's disease - SES-CD and CRP - were closely associated with HSP90α concentrations in plasma, suggesting that HSP90α may be a biomarker of Crohn's disease.

Mechanisms of Antiulcer Effect of an Active Ingredient Group of Modified Xiao Chaihu Decoction

The present study aimed to investigate the antiulcer activities and mechanisms of action of an active ingredient group (AIG) of Modified Xiao Chaihu Decoction (MXCD). The gastroprotective action of the AIG was studied in ethanol-induced, pylorus ligature-induced, and acetic acid-induced in vivo gastric ulcer models. The enzyme-linked immunoadsorbent assay (tumor necrosis factor-α (TNF-α), prostaglandin E₂ (PGE₂), and epidermal growth factor (EGF)), nitrate reductase assay (nitric oxide (NO)), western blot analysis (Bax, Bcl-2, cleaved-caspase-3, and cleaved-PARP (poly (ADP-Ribose) polymerase)), histological analysis (HE), and immunohistochemical analysis (HSP-70, p-AKT, and PCNA) were used to evaluate the anti-inflammatory, antiapoptotic, and healing properties of AIG. Numerous mechanisms are involved in the antiulcer activity of AIG, including the increase of PGE₂, NO, and EGF content and a reduction in TNF-α levels. The upregulation of HSP-70, p-AKT, and PCNA seems to be directly linked to the healing effect of AIG. Bax, Bcl-2, cleaved-caspase-3, and cleaved-PARP also play a key role in this process. The AIG exerted gastroprotective effects by reducing antisecretory, anti-inflammatory, and antiapoptotic mechanisms. In addition, it promotes cell proliferation. Therefore, activation of the PI3K/AKT signaling pathway may play an important role in cell proliferation.

Protective Effect of Cod (Gadus macrocephalus) Skin Collagen Peptides on Acetic Acid-Induced Gastric Ulcer in Rats

This research was performed to explore the protective effect of cod skin collagen peptides (CCP) on gastric ulcer induced by acetic acid. The CCP were fractionated into low molecular CCP (LMCCP, Mw < 3 kDa) and high molecular CCP (HMCCP, Mw > 3 kDa). In HMCCP and LMCCP, glycine of accounted for about one-third of the total amino acids without cysteine and tryptophan, and hydrophobic amino acids accounted for about 50%. After 21 d CCP treatment (60 or 300 mg/kg, p.o./daily), the healing effects on acetic acid-induced gastric ulcers were evaluated by macroscopic measure, microscopic measure, and immune histochemistry. Moreover, the expression levels of the growth factors, such as vascular endothelial growth factor, epidermal growth factor, transforming growth factor β1 (TGFβ1), and the heat shock protein 70 (HSP70) was detected. The results showed that both LMCCP and HMCCP could significantly decrease the ulcer areas and promote the healing of the lesions. They also could improve the levels of hexosamine, glutathione, superoxide dismutase, and glutathione peroxidase, and reduce the content of malondialdehyde and inducible nitric oxide synthase. In addition, the expression level of TGFβ1 gene and HSP70 mRNA was significantly improved by the treatment. It suggested that CCP could be able to improve symptoms of gastric ulcer and probably be used in the treatment of gastric ulcer.

The gastroprotective effect of pogostone from Pogostemonis Herba against indomethacin-induced gastric ulcer in rats

Pogostemonis Herba, known as "Guang-Huo-Xiang" in Chinese, has been widely used in the treatment of gastrointestinal dysfunction. Pogostone is one of the major constituents of Pogostemonis Herba. The aim was to scientifically evaluate the possible gastroprotective effect and the underlying mechanisms of pogostone against indomethacin-induced gastric ulcer in rats. Rats were orally treated with vehicle, lansoprazole (30 mg/kg) or pogostone (10, 20 and 40 mg/kg) and subsequently exposed to acute gastric lesions induced by indomethacin. Gross evaluation, histological observation, gastric mucosal superoxide dismutase activity, glutathione content, catalase activity, malonaldehyde level and prostaglandin E2 production were performed. Immunohistochemistry and reverse transcription polymerase chain reaction for cyclooxygenase-1 and cyclooxygenase-2, as well as terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling assay, immunohistochemistry for heat-shock protein 70, B-cell lymphoma-2 and Bax were conducted. Results indicated that rats pretreated with pogostone showed remarkable protection from the gastric mucosa damage compared to vehicle-treated rats based on the ulcer index and inhibition percentage. Histologically, oral administration of pogostone resulted in observable improvement of gastric injury, characterized by reduction of necrotic lesion, flattening of gastric mucosa and alleviation of submucosal edema with hemorrhage. Pogostone pretreatment significantly raised the depressed activities of superoxide dismutase, glutathione and catalase, while reduced the elevated malonaldehyde level compared with indomethacin-induced group. Pogostone-pretreated group induced a significant increase in gastric mucosal prostaglandin E2 level and obvious up-regulation of protein levels and mRNA expressions of cyclooxygenase-1 and cyclooxygenase-2. Furthermore, antiapoptotic effect of pogostone was verified by terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling assay, and the apoptotic process triggered by pogostone involved the up-expression of heat-shock protein70 and B-cell lymphoma-2 protein, and suppression of Bax protein expressions in the ulcerated tissues. It is speculated that the gastroprotective effect of pogostone against indomethacin-induced gastric ulceration might be associated with its stimulation of cyclooxygenase-mediated prostaglandin E2, antioxidant and antiapoptotic effect.

RETRACTED: Protective role of HSP70 against various gastrointestinal diseases

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the author. The article is a substantial duplicate of a paper that has already been published by the same author in Curr Pharm Des, 16 (2010) 1190-1196, http://dx.doi.org/10.2174/138161210790945986.

[Identification of a molecular mechanism for actions of existing medicines and its application for drug development]

As a new strategy for drug discovery and development, we propose here the establishment of drug re-profiling strategy. In this strategy, the actions of existing medicines, whose safety and pharmacokinetic effects in humans have been confirmed already, are examined comprehensively at the molecular level and the results are used for the development of new medicines. For example, identification of the mechanisms underlying the side effects of medicines enables us to develop safer drugs. The results can also be used for developing existing drugs for use as medicines in treatment of other diseases. Promoting this research strategy could provide breakthroughs in drug discovery and development by pharmaceutical companies.

Protective effect of Luffa acutangula extracts on gastric ulceration in NIDDM rats: role of gastric mucosal glycoproteins and antioxidants

OBJECTIVE

To study the comparative gastroprotective effect of Luffa acutangula methanolic extract (LAM) and aqueous extract (LAW) on type II diabetes rats.

METHODS

Streptozotocin (65 mg/kg, i.p.) along with nicotinamide (120 mg/kg, i.p.) was used to induce non insulin dependent diabetes mellitus (NIDDM) in rats. A daily oral dose of aspirin (200 mg/kg, i.p.) was administered for initial seven days to induce gastric ulcerations in the diabetic rats. LAM and LAW were administered orally in the doses of 100, 200 and 400 mg/kg once daily for 21 days. Glibenclamide and ranitidine were used as standards for comparing the antidiabetic and antiulcer effect respectively.

RESULTS

LAM significantly (P<0.01) increased mucosal glycoprotein and antioxidant enzyme level in gastric mucosa of diabetic rats than LAW (P <0.05). LAM was efficient in reversing the delayed healing of gastric ulcer in diabetic rats close to the normal level. LAM exhibited better ulcer healing effect than glibenclamide and LAW, because of its both antihyperglycemic and mucosal defensive actions.

CONCLUSIONS

Thus, LAM is proved to be a better alternative for treating gastric ulcers co-occurring with diabetes.

Mechanisms of action underlying the gastric antiulcer activity of the Rhizophora mangle L

ETHNOPHARMACOLOGICAL RELEVANCE

Rhizophora mangle, the red mangrove, has long been known as a traditional antiulcer medicine. The present work evaluated the mechanisms of action involved in the anti-ulcer properties of the Rhizophora mangle bark extracts.

MATERIALS AND METHODS

Gastroprotection of Rhizophora mangle was evaluated in rodent experimental models (ethanol). To elucidate the mechanisms of action the antisecretory action and involvement of NO, SH, mucus and PGE(2) were evaluated. The acetic acid-induced gastric ulcer model, Western blotting assay (COX-1, COX-2 and EGF) and immunohistochemical localization of HSP-70, PCNA and COX-2 were also used to evaluate the Rhizophora mangle healing properties.

RESULTS

Results showed that Rhizophora mangle bark crude extract (CE), as well as ethyl acetate (EtOAc) and butanolic fractions (BuOH) provided significant gastroprotection at all the tested doses. Thereby, the following protocols were performed using the lowest dose capable of producing the most effective gastroprotection, which was the BuOH 0.5mg/kg (P<0.001). Several mechanisms are involved in the antiulcer activity of Rhizophora mangle, such as, participation of NO, SH and mucus. The enhancement of PGE(2) levels and the upregulation of COX-2 and EGF seem to be directly linked to the antisecretory, cytoprotective and healing effects of BuOH. HSP-70 and PCNA are also involved in this cicatrisation process. No sign of toxicity was observed in this study, considering the analyzed parameters.

CONCLUSION

Our study reinforces its traditional medicinal use. Considering that the current therapies are based on the use of antisecretory or cytoprotective drugs, the Rhizophora mangle arises as a promising alternative antiulcer therapy.

Down-regulation of HSP70 sensitizes gastric epithelial cells to apoptosis and growth retardation triggered by H. pylori

BACKGROUND

H. pylori infection significantly attenuated the expression of HSP70 in gastric mucosal cells. However, the role of HSP70 cancellation in H. pylori-associated cell damages is largely unclear.

METHODS

Small interfering RNA (siRNA) was used to down-regulate HSP70 in gastric epithelial cell lines AGS. The transfected cells were then incubated with H. pylori and the functions of HSP70 suppression were observed by viability assay, cell cycle analyses and TUNEL assay. HSP70 target apoptotic proteins were further identified by Western blot.

RESULTS

The inhibition of HSP70 has further increased the effect of growth arrest and apoptosis activation triggered by H. pylori in gastric epithelial cells. The anti-proliferation function of HSP70 depletion was at least by up-regulating p21 and cell cycle modulation with S-phase accumulation. An increase of apoptosis-inducing factor (AIF) and cytosolic cytochrome C contributes to the activation of apoptosis following down-regulation of intracellular HSP70. Extracellular HSP70 increased cellular resistance to apoptosis by suppression the release of AIF and cytochrome c from mitochondria, as well as inhibition of p21 expression.

CONCLUSIONS

The inhibition of HSP70 aggravated gastric cellular damages induced by H. pylori. Induction of HSP70 could be a potential therapeutic target for protection gastric mucosa from H. pylori-associated injury.