Gastroprotective Effects of Glutinous Rice Extract against Ethanol-, Indomethacin-, and Stress-induced Ulcers in Rats

Tannic acid is a gastroprotective that regulates inflammation and oxidative stress

This study investigated the gastroprotective effect of TA against gastric ulcer in mice, and its possible mechanisms of action. The effects were investigated in a model of ethanol and ethanol/HCl induced ulcers, and physical barrier test. Quantification of oxidative stress mediators and inflammatory cytokines in gastric tissue was performed. The involvement of sulfhydryl compounds (-SH), nitric oxide (NO), prostaglandin E₂ (PGE₂), potassium channels (K ⁺_ATP) and opioid receptors in gastroprotection were investigated. Oral treatment with TA at a dose of 50 mg/kg resulted in 97.96% and 94.20% (reduction in gastric injury) of gastroprotection, against injuries caused by ethanol and ethanol/HCL, respectively, in addition to having a systematic effect. TA promotes increased levels of superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH), as well as reduced levels of malondialdehyde (MDA) reaction to thiobarbituric acid and myeloperoxidase (MPO). In addition, there was reduction in levels of tumor necrosis factor alpha (TNF-α) and interleukins (IL) IL-1β and IL-6 and increased IL-10. The gastroprotective activity of TA involved K ⁺_ATP channels and the production of -SH, NO and PGE_2, demonstrating multiple mechanisms of action. The results of the present study suggest that TA may be a gastroprotective agent counteracting oxidative and inflammatory stress.

Allantoin improves histopathological evaluations in a rat model of gastritis

PURPOSE

Gastritis is found to be one of the most common gastrointestinal diseases worldwide. However, current therapeutic agents cause side effects, interaction, and recurrence. Allantoin has anti-inflammatory and wound healing properties. In this study, the therapeutic effect of allantoin has been assessed on the histopathological indices and gastric mucosal barrier of male rats.

METHODS

Male rats were equally divided into control, ethanol-induced gastritis, and allantoin groups. The therapeutic groups consisted of gastritis plus 12.5 mg/kg allantoin, gastritis plus 25 mg/kg allantoin, and gastritis plus 50 mg/kg allantoin groups. After 5 days of allantoin administration, the rats were sacrificed and a part of their gastric tissue was maintained at -70 °C for prostaglandin E2 (PGE2) and non-protein sulfhydryl (NP-SH) measurements. Another part was stained with hematoxylin and eosin and Masson's trichrome.

RESULTS

We found that Allantoin increased parietal and mucosal cell counts and mucosal thickness after gastritis induction. In addition, the number of leukocytes and vessels decreased in both of the mucosal and the submucosal layers. Allatoin improved gastric ulcer in all treatment groups. Gastric levels of PGE2 and NP-SH increased after allantoin treatment.

CONCLUSION

This study indicated that allantoin had a considerable effect on gastritis treatment, which seems to result from the reinforcement of gastric mucosal barrier.

Potential Gastroprotective Activity of Rice Bran (Oryza sativa L.) Extracted by Ionic Liquid-Microwave-Assisted Extraction against Ethanol-Induced Acute Gastric Ulcers in Rat Model

The presence of gamma-oryzanol in rice bran oil can be 10⁻20-fold higher than tocopherol and tocotrienol. Gamma-oryzanol has various pharmacological properties. The objective of this study was to evaluate the effectiveness of rice bran extract as a gastroprotective in reducing lesions in ethanol-induced acute gastric ulcer models in rat, using the ionic liquid-microwave-assisted extraction (IL-MAE) method. Rice bran extract was obtained using the IL-MAE method with ionic liquid (IL), 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM]BF₄ (concentration 0.7 M), and a ratio of solid/liquid of 15 g/mL, 15 min extraction time, and 10% microwave power. The rats were pretreated with rice bran extract at different doses (100, 200, and 400 mg/kg body weight; BW) for seven days and subsequently exposed to acute gastric lesions induced by 80% ethanol. Omeprazole (36 mg/kg BW) was used as a standard anti-ulcer drug. The ulcer index, gastric juice acidity, and mucus levels were measured to assess the degree of gastroprotection. The results showed that the oral administration of rice bran extract at a dose of 400 mg/kg BW significantly inhibited the development of ulcer formation by 66.75% and reduced gastric acid levels. Moreover, gamma oryzanol and omeprazole protected the gastric mucosa from ethanol-induced gastric lesions by increasing the level of gastric mucus. Rice bran extract is effective as a gastroprotective therapy sourced from natural ingredients in treating the incidence of gastric ulcers. Most likely, this is related to gamma oryzanol as a bioactive compound contained in rice bran (Oryza sativa L.).

N-acetylcysteine a possible protector against indomethacin-induced peptic ulcer: crosstalk between antioxidant, anti-inflammatory, and antiapoptotic mechanisms

This study investigated the gastroprotective effects of N-acetylcysteine (NAC) against indomethacin-induced gastric ulcer in rats. Ulceration was induced by a single oral administration of indomethacin (30 mg/kg). 50 male albino rats were allocated into 5 equal groups: control group received normal saline orally, indomethacin group rats received normal saline orally for 5 days and indomethacin (50 mg/kg) on the last day, ranitidine group received ranitidine (reference drug) orally for 5 days (50 mg/kg) before receiving indomethacin (50 mg/kg) on the last day, and NAC groups received NAC orally at 300 and 500 mg/kg, respectively, for 5 days before receiving indomethacin (50 mg/kg) on the last day. Gastric tissue interleukin-1β (IL-1β), interferon-γ (IFN-γ), and caspase-3 levels were immunoassayed. Total thiol (T-SH), myeloperoxidase (MPO), and glucose-6-phosphate dehydrogenase (G6PD) were determined by spectrophotometry. Cytokine-induced neutrophil chemoattractant 2α (CINC-2α) gene expression was evaluated in addition to Bcl-2 immunohistochemistry. Pretreatment with NAC improved the inflammatory, apoptotic, and redox status in a dose-dependent manner particularly in NAC 500 mg/kg pretreated group. These results show a role for NAC in improving indomethacin-induced gastric ulceration via antioxidative, antiapoptotic, and anti-inflammatory interactive mechanisms.

Prostaglandin E2 stimulates urokinase-type plasminogen activator receptor via EP2 receptor-dependent signaling pathways in human AGS gastric cancer cells

Aberrant expression of urokinase-type plasminogen activator receptor (uPAR) has been observed in human gastric cancers. Prostaglandin E₂ (PGE₂ ), whose biosynthesis is catalyzed by cyclooxygenase-2 (COX-2), is implicated in cancer metastasis; however, the cellular and molecular mechanisms of PGE₂ -driven uPAR expression are yet to be elucidated in human gastric cancer AGS cells. In this study, we showed that PGE₂ induces uPAR expression in concentration- and time-dependent manners. Furthermore, using antagonists and siRNA, we found that among the four subtypes of PGE₂ receptors, EP2 receptors are involved in PGE₂ -induced uPAR expression. PGE₂ induced the activation of Src, epidermal growth factor receptor (EGFR), c-Jun NH₂ -terminal kinase (JNK), extracellular signal-regulated kinase (Erk), and p38 mitogen activated protein kinase (p38 MAPK). Specific inhibitor and mutagenesis studies showed that Src, EGFR, JNK1/2, and Erk1/2 are involved in PGE₂ -induced uPAR expression. PGE₂ induces EP2-dependent phosphorylation of Src, while the activation of Src-dependent EGFR leads to the phosphorylation of JNK1/2 and Erk1/2. Deletion and site-directed mutagenesis studies demonstrated the involvement of transcription factor activator protein (AP)-1 and nuclear factor-kappa B (NF-κB) in PGE₂ -induced uPAR expression. EGFR-dependent MAPKs (JNK1/2 and Erk1/2) function as the upstream signaling molecules in the activation of AP-1 and NF-κB, respectively. AGS cells pre-treated with PGE₂ showed remarkably enhanced invasiveness, which was partially abrogated by uPAR-neutralizing antibodies. To the best of our knowledge, this is the first report that PGE₂ -induced uPAR expression, which stimulates invasiveness of human gastric cancer AGS cells, is mediated by the EP2 receptor-dependent Src/EGFR/JNK1/2, Erk1/2/AP-1, and Src/EGFR/JNK1/2, Erk1/2/NF-κB cascades. © 2016 Wiley Periodicals, Inc.

Protective effect of diet supplemented with rice prolamin extract against DNCB-induced atopic dermatitis in BALB/c mice

Background

Rice prolamin has been reported to possess antioxidative, anti-inflammatory and immune-promoting properties. This study is aimed to examine the protective effects of dietary rice prolamin extract (RPE) against dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD)-like skin lesions in mice.

Methods

BALB/c mice were fed diet supplemented with 0–0.1 % RPE for 6 weeks. For the last 2 weeks, 1 % or 0.2 % DNCB was applied repeatedly to the back skin of mice to induce AD-like lesions. Following AD induction, the severity of skin lesions was examined macroscopically and histologically. In addition, the serum levels of IgE, IgG1 and IgG2a were determined by ELISA, and the mRNA expression of IL-4 and IFN-γ in the skin was determined by real-time PCR.

Results

Dietary RPE suppressed the clinical symptoms of DNCB-induced dermatitis as well as its associated histopathological changes such as epidermal hyperplasia and infiltration of mast cells and eosinophils in the dermis. RPE treatment also suppressed the DNCB-induced increase in transepidermal water loss. Dietary RPE inhibited the DNCB-induced enhancement of serum IgE and IgG1 levels, whereas it increased the serum IgG2a level in DNCB-treated mice. In addition, dietary RPE upregulated the IFN-γ mRNA expression and downregulated the IL-4 mRNA expression in the skin of DNCB-treated mice.

Conclusions

The above results suggest that dietary RPE exerts a protective effect against DNCB-induced AD in mice via upregulation of Th1 immunity and that RPE may be useful for the treatment of AD.

Chrysin inhibits tumor promoter-induced MMP-9 expression by blocking AP-1 via suppression of ERK and JNK pathways in gastric cancer cells

Cell invasion is a crucial mechanism of cancer metastasis and malignancy. Matrix metalloproteinase-9 (MMP-9) is an important proteolytic enzyme involved in the cancer cell invasion process. High expression levels of MMP-9 in gastric cancer positively correlate with tumor aggressiveness and have a significant negative correlation with patients’ survival times. Recently, mechanisms suppressing MMP-9 by phytochemicals have become increasingly investigated. Chrysin, a naturally occurring chemical in plants, has been reported to suppress tumor metastasis. However, the effects of chrysin on MMP-9 expression in gastric cancer have not been well studied. In the present study, we tested the effects of chrysin on MMP-9 expression in gastric cancer cells, and determined its underlying mechanism. We examined the effects of chrysin on MMP-9 expression and activity via RT-PCR, zymography, promoter study, and western blotting in human gastric cancer AGS cells. Chrysin inhibited phorbol-12-myristate 13-acetate (PMA)-induced MMP-9 expression in a dose-dependent manner. Using AP-1 decoy oligodeoxynucleotides, we confirmed that AP-1 was the crucial transcriptional factor for MMP-9 expression. Chrysin blocked AP-1 via suppression of the phosphorylation of c-Jun and c-Fos through blocking the JNK1/2 and ERK1/2 pathways. Furthermore, AGS cells pretreated with PMA showed markedly enhanced invasiveness, which was partially abrogated by chrysin and MMP-9 antibody. Our results suggest that chrysin may exert at least part of its anticancer effect by controlling MMP-9 expression through suppression of AP-1 activity via a block of the JNK1/2 and ERK1/2 signaling pathways in gastric cancer AGS cells.