Molecular docking, characterization, ADME/toxicity prediction, and anti-ulcer activity of new quercetin derivatives on indomethacin-induced gastric ulcer in mice

Gastric ulcer (GU) is a serious upper gastrointestinal tract disorder that affects people worldwide. The drugs now available for GU treatment have a high rate of relapses and drug interactions, as well as mild to severe side effects. As a result, new natural therapeutic medications for treating GU with fewer negative side effects are desperately needed. Because of quercetin's (QCT) diverse pharmacological effects and unique structural features, we decided to semi-synthesize new QCT derivatives and test them for antiulcer activity. Docking assays were performed on the synthesized compounds to determine their affinity for TLR-4/MD-2, MyD88/TIR, and NF-κB domains, an important inflammatory pathway involved in GU development and progression. Mice were given oral famotidine (40 mg/kg/day), QCT, QCT pentamethyl (QPM), or QCT pentaacetyl (QPA) (50 mg/kg/day) for 5 days before GU induction by a single intraperitoneal injection of indomethacin (INDO; 18 mg/kg). QPM and QPA have a stronger binding affinity for TLR-4/MD-2, MyD88/TIR and NF-κB domains than QCT. In comparison, they demonstrated the greatest reduction in ulcer score and index, gastric MDA and nitric oxide (NO) contents, MyD88 and NF-κB expressions, and gastric TLR-4 immunostaining. They also enhanced the levels of GSH, CAT, COX-1, and COX-2 in the gastric mucosa, as well as HO-1 and Nrf2 expression, with histological regression in gastric mucosal lesions, with QPA-treated mice demonstrating the best GU healing. QPA is safe against all of the target organs and adverse pathways studied, with good ADME properties. However, further in vitro experiments are necessary to demonstrate the inhibitory effects of QPM and QPA on the protein targets of interest. In addition, preclinical research on its bioavailability and safety is essential before clinical management can be undertaken. Overall, the new QPA derivative could one day serve as the basis for a new class of potential antiulcer drugs.

Brain oxidative stress mediates anxiety-like behavior induced by indomethacin in zebrafish: protective effect of alpha-tocopherol

RATIONALE

Indomethacin (INDO) is a widely utilized non-steroidal anti-inflammatory drug (NSAID) with recognized effect on the central nervous system. Although previous reports demonstrate that prolonged treatment with indomethacin can lead to behavioral alterations such as anxiety disorder, the biochemical effect exerted by this drug on the brain are not fully understood.

OBJECTIVES

The aim of present study was to evaluate if anxiety-like behavior elicited by indomethacin is mediated by brains oxidative stress as well as if alpha-tocopherol, a potent antioxidant, is able to prevent the behavioral and biochemical alterations induced by indomethacin treatment.

METHODS

Zebrafish were utilized as experimental model and subdivided into control, INDO 1 mg/Kg, INDO 2 mg/Kg, INDO 3 g/Kg, α-TP 2 mg/Kg, α-TP 2 mg/Kg + INDO 1 mg/Kg and α-TP + INDO 2 mg/Kg groups. Vertical distributions elicited by novelty and brain oxidative stress were utilized to determinate behavioral and biochemical alterations elicited by indomethacin treatment, respectively.

RESULTS

Our results showed that treatment with indomethacin 3 mg/kg induces animal death. No changes in animal survival were observed in animals treated with lower doses of indomethacin. Indomethacin induced significant anxiogenic-like behavior as well as intense oxidative stress in zebrafish brain. Treatment with alpha-tocopherol was able to prevent anxiety-like behavior and brain oxidative stress induced by indomethacin.

CONCLUSIONS

Data presented in current study demonstrated for the first time that indomethacin induces anxiety-like behavior mediated by brain oxidative stress in zebrafish as well as that pre-treatment with alpha-tocopherol is able to prevent these collateral effects.

Caffeic acid phenethyl ester attenuates indomethacin-induced gastric ulcer in rats

Gastric ulcer is one of the most frequent gastrointestinal ailments worldwide. Indomethacin, one of the most potent NSAIDs, suffers undesirable ulcerogenic activity. Caffeic acid phenethyl ester (CAPE) has known health benefits. The current study examined the potential of CAPE to combat indomethacin-induced gastric ulcers in rats. Animals were randomized into 5 groups: control, Indomethacin (50 mg/kg) mg/kg), Indomethacin + CAPE (5 mg/kg/day), Indomethacin + CAPE (10 mg/kg), and Indomethacin + Omeprazole (30 mg/kg). CAPE prevented the rise in ulcer index, attenuated histopathological changes and preserved gastric mucin concentration. CAPE efficiently significantly prevented accumulation of malondialdehude (MDA) and prevented exhaustion of the enzymatic activities of catalase (CAT) and superoxide dismutase (SOD). Further, CAPE prevented the rise in the expression of tumor necrosis factor-α (TNF-α), cyclo-oxygenase-2 (COX-2) and nuclear factor kapp-B (NFκB). This was associated with down-regulation of Bax and up-regulation of Bcl-2 mRNA. Finally, CAPE prevented induced indomethacin-induced decrease in heat shock protein 70 (HSP70) in gastric tissues. In conclusion, CAPE possesses the ability to prevent indomethacin-induced gastric ulcer in rats. This involves, at least partially, antioxidation, anti-inflammation, anti-apoptosis and enhancement of HSP70 expression.

Huang-Qi-Jian-Zhong-Tang accelerates healing of indomethacin-induced gastric ulceration in rats via anti-inflammatory and antioxidant mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Huang-Qi-Jian-Zhong-Tang (HQJZT) is a canonical traditional Chinese medicine (TCM) formula that has been widely used in both the prevention and treatment of gastrointestinal diseases, including gastric ulcer, duodenal ulcer, and chronic atrophic gastritis, in China.

AIM OF THE STUDY

In the present study, we investigated the gastroprotective potential of HQJZT in a rat model of indomethacin (IND)-induced gastric ulcer and explained the biochemical, cellular, and molecular mechanisms involved.

MATERIALS AND METHODS

Observations were conducted at the macroscopic level to ascertain the ulcer index (UI) and the curative index (CI). Histopathological examinations were conducted, and a microscopic score (MS) was computed. The gastric juice volume, total acidity, pH value, and pepsin activity were quantified. Antioxidant and oxidative parameters were assessed, namely GSH, CAT, SOD, and MDA content. The RFLSI Pro instrument was employed to measure the blood flow within the gastric mucosa continuously. The mRNA levels of the inflammatory cytokines were assessed using droplet digital PCR (ddPCR). Molecular docking was employed to examine the interaction between representative active components of HQJZT and the binding sites associated with the NF-κB and STAT signaling pathways. The protein expression and localization of p-JAK, p-STAT, p-IκBβ, and p-NF-κB were evaluated through immunofluorescence analysis.

RESULTS

The administration of HQJZT treatment demonstrated a significant reduction in gastric lesions induced by IND, leading to a notable decrease in the UI. Additionally, HQJZT treatment significantly decreased gastric juice volume, acidity, and pepsin activity, accompanied by increased pH value. IND-treated stomachs exhibited severe hemorrhagic necrosis, submucosal edema, and epithelial cell destruction. However, the administration of HQJZT effectively counteracted these pathological changes. Furthermore, HQJZT administration significantly increased blood flow to the gastric mucosa. HQJZT enhanced antioxidant defenses and modulated oxidative stress by increasing SOD, CAT, and GSH activities while reducing MDA levels. Moreover, HQJZT reversed IND-induced increases in mRNA expression levels of inflammatory cytokines. Molecular docking analysis revealed that the representative active components of HQJZT could bind to the NF-κB and STAT signaling pathways. In addition, immunofluorescence microscopy revealed that HQJZT markedly attenuated the phosphorylation of IκΒβ, NF-κB, JAK, and STAT.

CONCLUSIONS

The therapeutic and protective effect of HQJZT on gastric ulcers is attributed to its ability to suppress gastric acid secretion, enhance antioxidative defenses and blood flow, mitigate proinflammatory cytokines, and inhibit the activation of NF-κB and STAT signaling pathways.

Protective effect of Lizhong Pill on nonsteroidal anti-inflammatory drug-induced gastric mucosal injury in rats: Possible involvement of TNF and IL-17 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional Chinese medicine formula Lizhong Pill (LZP) and its herbal constituents are frequently utilized in Asian (China, Saudi Arabia, India, Japan, etc.) and some European (Russia, Sweden, UK, etc.) nations to treat various gastrointestinal ailments.

AIM OF THE STUDY

This study aimed to investigate the protective impact and potential mechanism of LZP against indomethacin (IND)-induced gastric mucosal injury in rats.

MATERIAL AND METHODS

Using a biochemical kit, we investigated the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) in rat serum, as well as pepsin in rat stomach tissue, using an IND-induced rat model of gastric mucosal injury. Various imaging tools, including HE staining, scanning electron microscopy (SEM), and transmission electron microscopy (TEM), were used to examine the gastric mucosa's surface morphology and ultrastructure. Furthermore, molecular docking was employed to predict the binding capacity of the primary bioactive components of LZP to the critical molecular protein targets in the IL-17 and TNF signaling pathways. At the same time, immunofluorescence was used to determine the protein expressions of CASP3, VCAM1, MAPK15, MMP3, IL-17RA, and TNFR1.

RESULTS

The present study demonstrates that LZP (3.75 and 7.50 g/kg) significantly reduces the gastric mucosal injury index induced by IND. This effect is evidenced by the improved morphology, surface, and structure of the gastric mucosa, as determined by HE, SEM, and TEM findings. Additionally, 3.75 and 7.50 g/kg LZP intervention significantly increased SOD and CAT contents and inhibited pepsin and GST activities. Molecular docking analysis revealed that the small molecular components of LZP can bind spontaneously to crucial proteins involved in the IL-17 and TNF signaling pathways, including MAPK15, MMP3, VCAM1, and CASP3. The immunofluorescence findings proved that LZP (3.75 and 7.50 g/kg) can inhibit the protein expressions of MAPK15, MMP3, VCAM1, CASP3, IL-17RA, and TNFR1.

CONCLUSIONS

Our investigation findings demonstrate that LZP can potentially ameliorate IND-induced damage to the gastric mucosa by inhibiting IL-17 and TNF signaling pathways. These results offer encouraging support for using alternative medicine to manage drug-induced gastric mucosal injury.

Low dose dietary contamination with deoxynivalenol mycotoxin exacerbates enteritis and colorectal cancer in mice

BACKGROUND

The mycotoxin deoxynivalenol (DON) is a frequent contaminant of grain and cereal products worldwide. Exposure to DON can cause gastrointestinal inflammation, disturb gut barrier function, and induce gut dysbiosis in vivo under basal conditions, but little is known about the effects of DON ingestion in individuals with pre-existing gastrointestinal disease.

OBJECTIVES

Mice were orally exposed to 10 and 100 μg/kg bw/day of DON, corresponding to 10 to 100-fold human tolerable daily intake concentrations, and to the translation in mice of current human daily intake. The effects of DON exposure were explored under steady-state conditions, and in murine models of enteritis and colorectal cancer (CRC).

RESULTS

After 8 days of DON exposure, an increase of histomorphological and molecular parameters of epithelial proliferation were observed in normal mice, from the duodenum to the colon. The same exposure in a murine model of indomethacin-induced enteritis led to exacerbation of lesion development and induction of ileal cytokines. DON exposure also worsened the development of colitis-associated CRC in mice as shown by increases in endoscopic and histological colitis scores, tumor grades, and histological hyperplasia. In colon of DON-exposed mice, upstream and downstream ERK signaling genes were upregulated including Mapk1, Mapk3, Map 2k1, Map2k2 core ERK pathway effectors, and Bcl2 and Bcl2l1 antiapoptotic genes. The effects observed in the CRC model were associated with alterations in cecal microbiota taxonomic composition and metabolism of bacterial fucose and rhamnose. Strong Spearman's correlations were revealed between the relative abundance of the changed bacterial genera and CRC-related variables.

DISCUSSION

Ingestion of DON mycotoxin at concentrations representative of human real-world exposure worsened the development of indomethacin-induced enteritis and colitis-associated CRC in mice. Our results suggest that even at low doses, which are currently tolerated in the human diet, DON could promote the development of intestinal inflammatory diseases and CRC.

Gastro-protective effect of l-arginine against nitric oxide deficiency-related mucosal injury induced by indomethacin: Does age matter?

Gastric ulcer is a common disease with increased prevalence in the aged population. Aged gastric mucosa has increased susceptibility to injury along with nonsteroidal anti-inflammatory drugs use due to impaired mucosal defense and decreased vasodilator release. We investigated whether l-arginine could protect against age-related gastric ulceration induced by indomethacin. Aged and adult male Wistar rats were administered sole and combined treatment of  l-arginine and Nω -nitro-l-arginine methyl ester ( l-NAME) before induction of gastric ulceration by indomethacin. The gastroprotective effect of  l-arginine was displayed only in adult rats with indomethacin-induced gastric ulceration, as evidenced by a significant decrease in ulcer index, oxidative stress parameters, and mucosal myeloperoxidase activity along with increased mucosal PGE2 levels. Interestingly, the mucosal gene expressions of NF-кB, iNOS, and COX-2 were significantly suppressed by  l-arginine pretreatment and aggregated upon pretreatment with  l-NAME in both adult and aged rats treated with indomethacin. In conclusion,  l-arginine protected the rats' gastric mucosa against indomethacin-induced gastric ulceration, possibly, at least in part, by enhancement of mucosal nitric oxide/PGE2 content along with suppressing gastric inflammation and oxidative stress. This study supposed that the gastroprotective effect of  l-arginine depends on aging, and even so, the adoption of a new approach to gastric ulcer treatment for the aged population is warranted.

Flavonoid-Rich Sambucus nigra Berry Extract Enhances Nrf2/HO-1 Signaling Pathway Activation and Exerts Antiulcerative Effects In Vivo

Sambucus nigra (SN) berry extract is characterized by high antioxidant and anti-inflammatory activity. The current study aimed to investigate the effect of SN berry extract against indomethacin (IND)-induced gastric ulcer in rats and the mechanism involved. SN berry extract alleviated IND-induced gastric ulcers, as shown by assessing pathological manifestations in the gastric mucosa. These protective effects are attributed to attenuated oxidative damage to the gastric mucosa, correlated to increased activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), enhanced glutathione (GSH) levels, total antioxidant capacity (TAC), and upregulation of the Nrf2/HO-1 cascade. Moreover, oxidative stress markers, including malondialdehyde (MDA) and total oxidant status (TOS), were downregulated in SN-extract-treated animals. Furthermore, SN berry extract suppressed gastric mucosal inflammation by downregulating interleukin (IL)-33, IL-1β, IL-6, and tumor necrosis factor-alpha (TNF-α) levels, and attenuating myeloperoxidase (MPO) activity. The protective effects of SN berry extract were similar to those exerted by esomeprazole (ESO), an acid-secretion-suppressive drug. In conclusion, SN berry extract has antiulcerative effects, alleviating oxidative stress and inflammation.

Honokiol, an inducer of sirtuin-3, protects against non-steroidal anti-inflammatory drug-induced gastric mucosal mitochondrial pathology, apoptosis and inflammatory tissue injury

BACKGROUND AND PURPOSE

Mitochondrial oxidative stress, inflammation and apoptosis primarily underlie gastric mucosal injury caused by the widely used non-steroidal anti-inflammatory drugs (NSAIDs). Alternative gastroprotective strategies are therefore needed. Sirtuin-3 pivotally maintains mitochondrial structural integrity and metabolism while preventing oxidative stress; however, its relevance to gastric injury was never explored. Here, we have investigated whether and how sirtuin-3 stimulation by the phytochemical, honokiol, could rescue NSAID-induced gastric injury.

EXPERIMENTAL APPROACH

Gastric injury in rats induced by indomethacin was used to assess the effects of honokiol. Next-generation sequencing-based transcriptomics followed by functional validation identified the gastroprotective function of sirtuin-3. Flow cytometry, immunoblotting, qRT-PCR and immunohistochemistry were used measure effects on oxidative stress, mitochondrial dynamics, electron transport chain function, and markers of inflammation and apoptosis. Sirtuin-3 deacetylase activity was also estimated and gastric luminal pH was measured.

KEY RESULTS

Indomethacin down-regulated sirtuin-3 to induce oxidative stress, mitochondrial hyperacetylation, 8-oxoguanine DNA glycosylase 1 depletion, mitochondrial DNA damage, respiratory chain defect and mitochondrial fragmentation leading to severe mucosal injury. Indomethacin dose-dependently inhibited sirtuin-3 deacetylase activity. Honokiol prevented mitochondrial oxidative damage and inflammatory tissue injury by attenuating indomethacin-induced depletion of both sirtuin-3 and its transcriptional regulators PGC1α and ERRα. Honokiol also accelerated gastric wound healing but did not alter gastric acid secretion, unlike lansoprazole.

CONCLUSIONS AND IMPLICATIONS

Sirtuin-3 stimulation by honokiol prevented and reversed NSAID-induced gastric injury through maintaining mitochondrial integrity. Honokiol did not affect gastric acid secretion. Sirtuin-3 stimulation by honokiol may be utilized as a mitochondria-based, acid-independent novel gastroprotective strategy against NSAIDs.

Protective effects of Saccharomyces boulardii CNCM I-745 in an experimental model of NSAID-induced enteropathy

Nonsteroidal anti-inflammatory drugs (NSAIDs) induce a broad spectrum of gastro-intestinal adverse effects, including ulceration and bleeding. The pathophysiology of NSAID enteropathy is complex and incompletely understood, but some evidence showed that NSAIDs impair the intestinal barrier and cause a gut dysbiosis. Identifying new treatments aiming to reverse or attenuate NSAID-induced adverse effects would have a significant impact on a high number of patients. The aim of this work is to assess the effects of the probiotic yeast Saccharomyces boulardii CNCM I-745 (Sb) on a model of NSAID-induced enteropathy. Four groups of mice were tested: Control, Indomethacin, Sb, and Sb + Indomethacin. A clinical score was evaluated throughout the experiment. Faecal calprotectin, microbiota and haemoglobin analyses were performed. At the end of the treatments, the small intestine, colon, and caecum lengths, and intestinal permeability were measured. Sections of ileum and jejunum were observed to assess a histological score and ileal cytokines were measured by immunoassay. Indomethacin-treated animals showed an increase in their clinical scores, reflecting a worsening of their general state. Mice co-treated with Sb and indomethacin displayed an improvement of their clinical score in comparison with mice treated with indomethacin alone. Sb prevented the indomethacin-induced shortening of the small intestine and caecum, and significantly attenuated the severity of intestinal lesions. Sb also prevented the increase in faecal calprotectin, reduced faecal haemoglobin, and prevented the increase of intestinal permeability in mice treated with indomethacin. Sb also counteracted the increase of faecal bacteria associated with the pathogenesis of NSAID-enteropathy. In conclusion, our results show a protective effect of Sb in a model of indomethacin-induced enteropathy. Sb improved the intestinal barrier function and exerted a positive action on gut microbiota composition.

Systems-level multi-omics characterization provides novel molecular insights into indomethacin toxicity

The mechanism of indomethacin toxicity at the systemic level is largely unknown. In this study, multi-specimen molecular characterization was conducted in rats treated with three doses of indomethacin (2.5, 5, and 10 mg/kg) for 1 week. Kidney, liver, urine, and serum samples were collected and analyzed using untargeted metabolomics. The kidney and liver transcriptomics data (10 mg indomethacin/kg and control) were subjected to a comprehensive omics-based analysis. Indomethacin exposure at 2.5 and 5 mg/kg doses did not cause significant metabolome changes, whereas considerable alterations in the metabolic profile compared to the control were induced by a dose of 10 mg/kg. Decreased levels of metabolites and an increased creatine level in the urine metabolome indicated injury to the kidney. The integrated omics analysis in both liver and kidney revealed an oxidant-antioxidant imbalance due to an excess of reactive oxygen species, likely originating from dysfunctional mitochondria. Specifically, indomethacin exposure induced changes in metabolites related to the citrate cycle, cell membrane composition, and DNA synthesis in the kidney. The dysregulation of genes related to ferroptosis and suppression of amino acid and fatty acid metabolism were evidence of indomethacin-induced nephrotoxicity. In conclusion, a multi-specimen omics investigation provided important insights into the mechanism of indomethacin toxicity. The identification of targets that ameliorate indomethacin toxicity will enhance the therapeutic utility of this drug.

Protective effect of valerian extract capsule (VEC) on ethanol- and indomethacin-induced gastric mucosa injury and ameliorative effect of VEC on gastrointestinal motility disorder

CONTEXT

Valerian extract capsule (VEC) is an effective Chinese patent medicine used for gastrointestinal (GI) diseases.

OBJECTIVE

To investigate the detailed pharmacological activity for VEC clinical effects in GI diseases.

MATERIALS AND METHODS

Sprague-Dawley rats were divided into six groups: control, model, and drug-treated (VEC-L, VEC-M, VEC-H, and teprenone). Rats were orally administered VEC (124, 248, 496 mg/kg) and teprenone (21.43 mg/kg) for 3 consecutive days. After 1 h, the five groups (except the control group) were orally given ethanol (10 mL/kg) for 1 h or indomethacin (80 mg/kg) for 7 h. The spasmolytic activity of VEC (0.01-1 mg/mL) on ACh/BaCl₂-induced New Zealand rabbit smooth muscle contraction was performed. The C57BL/6 mice carbon propelling test evaluated the effects of VEC (248-992 mg/kg) on intestinal motility in normal and neostigmine/adrenaline-induced mice.

RESULTS

Compared with the model group, VEC treatment reduced the gastric lesion index and mucosal damage. Further experiments showed that the pathological ameliorative effect of VEC was accompanied by augmentation of the enzymatic antioxidant system and cytoprotective marker (COX-1, p < 0.01; PGI2 p < 0.05;), along with the alleviation of the levels of MPO (ethanol: 15.56 ± 0.82 vs. 12.15 ± 2.60, p < 0.01; indomethacin: 9.65 ± 3.06 vs. 6.36 ± 2.43, p < 0.05), MDA (ethanol: 1.66 ± 0.44 vs. 0.81 ± 0.58, p < 0.01; indomethacin: 1.71 ± 0.87 vs. 1.09 ± 0.43, p < 0.05), and inflammatory mediators. VEC decreased the high tone induced by ACh/BaCl₂ and promoted intestinal transit in normal and neostigmine/adrenaline-induced mice.

DISCUSSION AND CONCLUSIONS

VEC showed a potential gastroprotective effect, suggesting that VEC is a promising phytomedicine for the treatment of GI diseases.

Rivastigmine ameliorates indomethacin experimentally induced gastric mucosal injury via activating α7nAChR with inhibiting oxidative stress and apoptosis

The current study aimed to investigate the potential ameliorative role of Rivastigmine (RIVA), the anti-Alzheimer drug, against the gastric mucosal injury caused by indomethacin (IND). The rats were divided into four groups: group I was given a vehicle as a control, group II was given RIVA (0.3 mg/kg) once daily intraperitoneal (ip) for 2 weeks, group III was given a single IP dose of 30 mg/kg IND, and group IV was given RIVA ip 2 weeks before the administration of IND. The gastric mucosal injury was detected by the estimation of ulcer index, gastric acidity, pepsin, and mucin concentrations. Malondialdehyde (MDA), superoxide dismutase (SOD), reduced glutathione (GSH), total nitrite/nitrate (NOx), and the expression of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), nuclear factor kappa B (NF-κB), Hemoxygenase 1 (HO-1), and caspase-3 were all measured in gastric tissue. In addition, histological assessment and proliferating cell nuclear antigen (PCNA) immuno-expression were studied. Gastric mucosal injury induced by IND was indicated by both biochemical and histopathological assessments. RIVA Pretreatment reduced ulcer index, MDA, TNF-α, IL-6, NF-κB, and caspase-3 and increased SOD, GSH, NOx, and HO-1. RIVA improved the suppressed nuclear immunoreaction for PCNA observed with IND. The current findings provide novel evidence that RIVA possesses a prophylactic action against IND-induced gastric mucosal damage in rats. Despite being a cholinergic drug that is associated with increased pepsin and stomach acidity, RIVA protected against IND-induced gastric mucosal injury via activating α7nAChR and inhibiting oxidative stress and apoptosis.

Chinese sumac (Rhus chinensis Mill.) fruits alleviate indomethacin-induced gastric ulcer in mice by improving oxidative stress, inflammation and apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

According to traditional Chinese medicine and a previous literature, many parts of Chinese sumac (Rhus chinensis Mill.), including fruits, are used as traditional herb to prevent or cure many diseases, such as inflammation, diarrhea, malaria, and other acute or chronic gastrointestinal diseases. However, the effects of the fruits on the prevention of gastric ulcer and the underlying mechanisms have not been reported.

AIM OF THE STUDY

This experiment aimed to investigate the preventive effect of ethanol extract (RM) from Chinese sumac fruits on indomethacin-induced gastric ulcer in mice and the underlying mechanisms.

MATERIALS AND METHODS

A single gavage of indomethacin was used to induce a gastric ulcer model in Kunming male mice. According to the results of histopathological analysis, immunohistochemistry and immunofluorescence analysis, as well as the expression of prostaglandin E-2, antioxidant enzymes and cytokines, the protective effect of RM on indomethacin-induced gastric ulcer was evaluated. The expression levels of several key proteins involved in oxidative stress, inflammation and apoptosis in gastric tissue were detected to illuminate the underlying mechanisms.

RESULTS

RM significantly reduced the ulcer index and pepsin activity, improved the microstructure of gastric mucosa and the prostaglandin E-2 content, restored the levels of glutathione and superoxide dismutase, and decreased the contents of malondialdehyde, advanced oxidation protein products, TNF-α, IL-1 β and IL-6. Further experimental results showed that RM could improve the expression levels of HO-1 and NQO1 by activating the Nrf2 protein pathway to alleviate oxidative stress in gastric tissue. At the same time, RM significantly down-regulated the expressions of p-NF-κB, p-IκBα and iNOS to relieve inflammatory response, and inhibited the cellular apoptosis of gastric tissue by up-regulating Bcl-2 and down-regulating Bax and cleaved Caspase-3.

CONCLUSIONS

The current work clarified that the ethanol extract from Chinese sumac fruits can improve the oxidative stress level, inflammatory response and cell apoptosis in gastric tissue by interfering with the expressions of several key regulatory proteins to prevent indomethacin-induced gastric ulcer in mice. This study may provide some insights and scientific evidence on the application of Chinese sumac fruits as a traditional herb to prevent or alleviate gastric ulcer.

Eremomastax speciosa (Hochst.) Cufod. counteracts the delaying effect of indomethacin on Helicobacter pylori-associated chronic gastric ulcers healing

ETHNOPHARMACOLOGICAL RELEVANCE

Information collected from local traditional healers reported that Eremomastax speciosa (Hochst.) Cufod. has for a long time been used to manage gastric ulcers in many regions of Cameroon and beyond. This traditional use is supported by numerous studies. However, efficacy of this plant has never been tested in case of chronic gastric ulcers associating Helicobacter pylori infection.

AIM OF THE STUDY

This study was designed to investigate curative effects of the aqueous extract of E. speciosa leaves (AEESL) against chronic gastric ulcers associated to Helicobacter pylori infection.

MATERIALS AND METHODS

Two experimental methods of chronic gastric ulcers, involving H. pylori infection, were performed using Wistar rats, namely: acetic acid-induced ulcers and "unhealed ulcers". E. speciosa extract was tested at three doses (100; 200; 400 mg/kg) and at the end of experiments, some in vivo antioxidant parameters were measured, bacterial load in stomach tissue calculated and histopathological examinations performed.

RESULTS

E. speciosa reduced ulcer index at all the doses and significantly increased mucus production as well as antioxidant (mainly SOD and GSH) level. Bacterial load in stomach significantly decreased (p < 0.05) in extract-treated groups (200 and 400 mg/kg) as confirmed by histopathological observations. The extract was found to be non toxic to healthy and cancerous cells (IC₅₀ > 1000 μg/mL).

CONCLUSIONS

E. speciosa accelerated healing of gastric ulcers even in presence of indomethacin, while decreasing bacterial loads in rats' stomachs. These results provide supplementary support to the use of E. speciosa in ethnomedicine and open new perspectives regarding development of a herbal-based monotherapy able to efficiently replace/supplement standard antiulcer tri/quadritherapy.

Peripheral corticotropin-releasing hormone may protect the gastric musosa against indometacin-induced injury through involvement of glucocorticoids

The hypothalamic-pituitary-adrenocortical (HPA) system is a key hormonal branch of the brain-gut axis in stress and corticotropin-releasing hormone (CRH) is a principal stimulator of the HPA system. According to our finding activation of the HPA system has gastroprotective role in stress and CRH may protect the gastric mucosa against stress-induced injury through involvement of glucocorticoids. To extend this idea to indomethacin-induced gastric injury in the present work we studied whether CRH may protect the gastric mucosa against ulcerogenic action of indomethacin (IM) through involvement of glucocorticoids. CRH administration (1.25 μg/kg and 2.5 μg/kg, i.p.) markedly, dose-dependently, increased plasma corticosterone level and significantly, dose-dependently, suppressed the occurrence of gastric erosion induced by IM (35 mg/kg, s.c.) in conscious rats. To estimate the role of glucocorticoids in CRH-induced gastroprotection, the effect of CRH (1.25 μg/kg) on the IM-induced gastric erosion was studied after acute reduction of corticosterone release by metyrapone (30 mg/kg, i.p., 30 min before CRH administration) or by CRH receptor type 1 antagonist NBI 27914 (10 mg/kg, i.p., 15 min before CRH administration) and also after occupation of glucocorticoid receptors by their antagonist RU-38486 (20 mg/kg, i.p., 2 h before CRH administration). The effects were compared with those in control rats without acute reduction of corticosterone release or occupation of glucocorticoid receptors. Both metyrapone and NBI 27914 injected shortly before CRH administration caused an inhibition of CRH-induced corticosterone response and prevented protective effect of CRH on the gastric mucosa against the IM-induced erosion. The gastroprotective effect of CRH was also eliminated by the pretreatment with glucocorticoid receptor antagonist RU-38486. The results obtained suggest that exogenous CRH may protect the gastric mucosa against IM-induced gastric injury through involvement of glucocorticoids.

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

ETHNOPHARMACOLOGICAL RELEVANCE

Elaeagnus 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 STUDY

Phytochemical investigation and assessment of pharmacological mechanism(s) involved in anti-ulcer effect of methanolic extract of the seeds of E. conferta.

MATERIALS AND METHODS

Bioactive 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.

RESULTS

Chromatography 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.

CONCLUSIONS

The 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.

Zuojin Pill ameliorates inflammation in indomethacin-induced gastric injury via inhibition of MAPK pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Zuojin Pill (ZJP) has been a classic prescription for the treatment of gastrointestinal diseases in China since ancient times. But its effect on non-steroidal anti-inflammatory drugs (NSAIDs) induced gastric injury (GI) is still uncharted.

AIM OF THE STUDY

This study aims to investigate the therapeutic effect and molecular mechanism of ZJP on indomethacin (IDO) induced gastric injury.

MATERIALS AND METHODS

GI was induced in rat by oral administration of 5 mg/kg IDO. Then the rats were treated with ZJP (1.26, 2.52, 5.04 g/kg, ig). The changes of food intake, body weight, gastric pH and general state observation were carried out to determine the improvement of ZJP in IDO-induced GI: HE staining and AB-PAS staining was analyzed to characterize the thickness of gastric mucosa and micro mucosal injury; in order to elucidate the effect of ZJP on IDO-induced inflammatory injury, the inflammatory infiltration of gastric tissue was observed by MPO immunohistochemical method, and the contents of TNF-α, IL-6 and IL-10 were measured. Furthermore, the regulatory mechanism of ZJP in treating IDO-induced GI was predicted with the help of network pharmacology, and the expression levels of key proteins ERK, p-ERK, P38, p-P38, JNK, p-JNK were determined to elucidate the molecular mechanism of ZJP.

RESULTS

Current data strongly demonstrated that ZJP alleviated food intake reduction, weight loss and gastric injury caused by IDO and made gastric pH and mucosal thickness return to normal. In addition, ZJP could reduce the level of MPO to alleviate the inflammatory infiltration of gastric tissue. Simultaneously, ZJP could down regulate the expression of TNF-α and IL-6 and up regulate the expression of IL-10 to reduce the damage caused by inflammatory, and create a healing environment. Furthermore, ZJP could significantly inhibit the phosphorylation of ERK, p38 and JNK, which leaded to the increase of inflammatory factors and the damage of gastric mucosa.

CONCLUSION

ZJP improved local inflammation by inhibiting MAPK signaling pathway, and had a good therapeutic effect on IDO-induced GI. This study has reference significance for the study of ZJP in the prevention and treatment of NSAID induced gastric injury. In addition, ZJP may be a new treatment option for the prevention and treatment of NSAID induced gastric disease.

Protective and therapeutic effects of the flavonoid "pinocembrin" in indomethacin-induced acute gastric ulcer in rats: impact of anti-oxidant, anti-inflammatory, and anti-apoptotic mechanisms

Peptic ulcer including gastric and duodenal ulcers is a common gastro-intestinal disorder worldwide, associated with a significant mortality due to bleeding and perforation. Numerous efforts are being exerted to look for natural drugs that lack the potential side effects but still keep beneficial effects for treatment and/or prevention of gastric ulcer. Pinocembrin (PINO) is a natural flavonoid retaining anti-microbial, anti-oxidant, and anti-inflammatory activities. The present study was conducted to investigate the protective and therapeutic effects of PINO against indomethacin (INDO)-induced gastric ulcer in rats and the possible underlying mechanisms. PINO (25 and 50 mg/kg) promoted mucus secretion, decreased ulcer index, and inhibited histopathological changes induced by INDO. Further investigation of possible mechanisms showed that PINO significantly attenuated INDO-induced oxidative and inflammatory responses in both doses when administrated before or after ulcer induction. PINO downregulated mRNA expression level of p38-mitogen-activated protein kinase (p38-MAPK) which subsequently inhibited NF-κB activation and inflammatory cytokine release including tumor necrosis factor-α (TNF-α) and interleukin-1beta (IL-1β). Additionally, PINO inhibited apoptotic activity which was confirmed by downregulation of caspase-3 transcription. The current results demonstrated the promising therapeutic activity of PINO against INDO-induced gastric ulcer due to-at least partly-its anti-oxidant, anti-inflammatory, and anti-apoptotic effects.

Evaluation of the gastroprotective effects of Chihuahua propolis on indomethacin- induced gastric ulcers in mouse

The aim of this work was to evaluate the gastroprotective activity of a Mexican propolis on indomethacin-induced gastric ulcers in a mouse model. The following contents of the ethanolic extract of propolis of Chihuahua (EEPCh) were determined: antioxidant activity (SA50), total phenolic content (TPC), total flavonoid content (TFC), and chemical composition by HPLC-DAD and HPLC-MS, as well as acute toxicity by OECD Guideline 423. Gastric lesions were induced by intragastric indomethacin treatment in male ICR mice. As the positive control, omeprazole was administered, and three doses of EEPCh were evaluated (50, 150 and 300 mg/kg). Gastric mucosal injury, histological changes and mucosal content were evaluated by means of H&E and PAS staining. For homogenized gastric tissues, the following were evaluated: TBARS, MPO, and PGE2 levels; SOD and GPx antioxidant enzymatic activity; and the concentrations of the proinflammatory cytokines, TNF-α, IL-1β and IL-6. EEPCh had a significant SA50 of 41.55 µg/mL. The TPC of EEPCh was 860 mg GAE/g, and its TFC was 49.58 mg QE/g. Different phenolic compounds were identified in the extract and were not toxic. The EEPCh doses decreased mucosal damage and histological injuries, maintained the mucosal content and reduced the TBARS, MPO and concentrations of proinflammatory cytokines in gastric ulcer tissues. The 150 and 300 mg/kg doses increased the SOD activity and maintained the PGE2 content. Only the 300 mg/kg dose increased the GPx activity. The results of this study suggest that EEPCh displays gastroprotective effects by means of its antioxidant activity and anti-inflammatory effects and promotes ulcer protection through the maintenance of mucosal content and PGE2 levels.

Pretreatment of IEC-6 cells with quercetin and myricetin resists the indomethacin-induced barrier dysfunction via attenuating the calcium-mediated JNK/Src activation

This study investigated the protective effect of two flavonols quercetin and myricetin on barrier function of rat intestinal epithelial (IEC-6) cells with indomethacin injury. When the cells were pretreated with the heated or unheated flavonols of 2.5-10 μmol/L for 24-48 h and then injured by 300 μmol/L indomethacin for 24 h, they showed reduced lactate dehydrogenase release (LDH) but increased cell viability; however, the flavonols of 20 μmol/L exerted a little effect to increase cell viability or decrease LDH release. Cell pretreatment with 5 μmol/L flavonols also resisted cell barrier dysfunction by increasing transepithelial resistance, reducing paracellular permeability, and promoting mRNA and protein expression of three tight junction proteins zonula occluden-1, occludin, and claudin-1. Although indomethacin injury increased intracellular Ca²⁺ concentration ([Ca²⁺]_i) and consequently caused JNK/Src activation, the flavonols could decrease [Ca²⁺]_i and attenuate the calcium-mediated JNK/Src activation. Quercetin with less hydroxyl groups was more efficient than myricetin to resist barrier dysfunction, while the unheated flavonols were more active than the heated counterparts to perform this effect. It is thus proposed that quercetin and myricetin could resist barrier dysfunction of the intestine once injured by indomethacin, but heat treatment of flavonols had a negative impact on barrier-protective function of flavonols.

Attenuating Effect of Telfairia occidentalis on Oxidative Stress in Indomethacin-induced Gastric Ulcer in Male Rats

Peptic ulcer is a major health challenge with high morbidity and mortality all over the world. This study investigated the involvement of oxidative stress in the healing and protective potentials of aqueous leave extract of Telfairia occidentalis (TO) on indomethacin induced gastric ulcers in adult Sprague Dawley male rats. The rats were divided into 6 groups (A-F) of 5 rats each, with A as normal control, B received single oral administration of 40mg/kg indomethacin without treatment for 4 hours; C received 40mg/kg indomethacin without treatment for 4 hours and scarified after 72 hours; D received 100mg/kg aqueous leave extract of TO for 7 days without ulcer induction; E (pre-treated test group) received 40mg/kg indomethacin after being pre-treated with 100mg/kg aqueous leave extract of TO daily for 7 days. Group F (Posttreated test) received 40mg/kg of indomethacin and treated four hours later with 100mg/kg aqueous leave extract of TO daily for 7 days. The results revealed changes in gastric macroscopic architecture of the mucosa, and changes in ulcer indices and oxidative stress markers levels in group B-F. These changes comparatively suggested that the leave-extract of Telfairia occidentalis has gastro-protective with minimal healing potentials mediated through reduced oxidative stress.

Revaprazan prevented indomethacin-induced intestinal damages by enhancing tight junction related mechanisms

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most commonly prescribed medications for alleviating pain and inflammation but may cause gastrointestinal tract damage. Proton pump inhibitors (PPI) prevent NSAID-induced gastric damage but may aggravate intestinal damage via dysbiosis and intestinal permeability alteration. Currently, there is growing interest regarding the influence of potassium competitive acid blockers (PCAB) on NSAID-induced enteropathy. Here, we investigated the relative changes in indomethacin-induced enteropathy by combining indomethacin with pantoprazole (as PPI) or revaprazan (as PCAB). We examined intestinal permeability-related molecular changes in in vitro Caco-2 cell models and in an in vivo indomethacin-induced enteropathy rat model. Indomethacin alone or in combination with pantoprazole significantly increased relative lucifer yellow dye flux and decreased relative trans-epithelial electrical resistance and tight junction protein (TJP) expression compare to normal cells. In contrast, indomethacin combined with revaprazan significantly preserved TJPs compare to indomethacin-treated cells. MLC phosphorylation, Rho activation, and ERK activation responsible for TJP were significantly increased by indomethacin alone or a combination of indomethacin and pantoprazole but not by a combination of indomethacin and revaprazan. Intestinal damage scores significantly increased with indomethacin and pantoprazole combination but not with indomethacin and revaprazan combination. Indomethacin and pantoprazole combination significantly activated Rho-GTPase, p-MLC, and p-ERK but significantly decreased TJP expression. However, indomethacin and revaprazan combination significantly preserved TJPs and inactivated Rho-GTPase, MLC, and ERK. Hence, revaprazan rather than PPIs should be co-administered with NSAIDs to mitigate NSAID-induced intestinal damage.

Detection, transformation, and toxicity of indole-derivative nonsteroidal anti-inflammatory drugs during chlorine disinfection

As important emerging contaminants, nonsteroidal anti-inflammatory drugs (NSAIDs) are the most intensively prescribed pharmaceuticals introduced to drinking water due to their incomplete removal in wastewater treatment. While concentrations of NSAIDs in drinking water are generally low, they have been attracting increasing concern as a result of their disinfection byproducts (DBPs) generated in drinking water disinfection. In this work, detection methods were set up for four representative indole-derivative NSAIDs (indomethacin, acemetacin, sulindac, and etodolac) using ultra performance liquid chromatography/electrospray ionization-triple quadruple mass spectrometry (UPLC/ESI-tqMS). ESI+ was better for detection of indomethacin and sulindac, whereas ESI- was suitable to detection of acemetacin and etodolac. With optimized MS parameters, the instrument detection and quantitation limits of the four indole derivatives were achieved to be 1.1-24.6 ng/L and 3.7-41.0 ng/L, respectively. During chlorination, indomethacin and acemetacin could undergo five major reaction types (chlorine substitution, hydrolysis, decarboxylation, C-C coupling, and C-N cleavage) to form a series of DBPs, among which 19 were proposed/identified with structures. Based on the revealed structures of DBPs, transformation pathways of indomethacin and acemetacin in chlorination were partially elucidated. Notably, individual and mixture toxicity of indomethacin and acemetacin before/after chlorination were evaluated using a well-established acute toxicity assessment and a Hep G2 cell cytotoxicity assay, respectively. Results showed that the predicted acute toxicity of a few chlorination DBPs were higher than their precursors; chlorination substantially enhanced the mixture cytotoxicity of indomethacin by over 10 times and slightly increased the mixture cytotoxicity of acemetacin.

The Protective Effect of 5-Aminosalicylic Acid Against Non-Steroidal Anti-Inflammatory Drug-Induced Injury Through Free Radical Scavenging in Small Intestinal Epithelial Cells

Background and objectives: Non-steroidal anti-inflammatory drugs (NSAIDs) have been among the major causes of small intestinal injury in clinical practice. As such, the current study investigated the protective effect of 5-aminosalicylic acid (5-ASA) against an NSAID-induced small intestinal injury. Materials and Methods: IEC-6 cells were treated with various concentrations of indomethacin with or without 5-ASA in a serum-free medium, after which an 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Dromide (MTT) assay, a cell apoptosis assay, a caspase-3 activity assay, a reactive oxygen species (ROS) content and Superoxide dismutase 2 (SOD2) activity measurement, a Western blotting for occludin and zonula occludens-1 (ZO-1) and a wound healing assay were conducted. Results: 5-ASA ameliorated indomethacin-induced cell apoptosis and an increase in the intracellular ROS content while augmenting the indomethacin-induced suppression of SOD2 activity in IEC-6 cells. Moreover, 5-ASA reversed the indomethacin-induced attenuation of occludin and ZO-1 expression and promoted faster wound healing effects in IEC-6 cells following an indomethacin-induced injury. Conclusions: Our results suggested that 5-ASA protects small intestinal cells against an NSAID-induced small intestinal injury by scavenging free radicals. Therefore, 5-ASA could be a potential treatment for an NSAID-induced small intestinal injury.

Glycomacropeptide Ameliorates Indomethacin-Induced Enteropathy in Rats by Modifying Intestinal Inflammation and Oxidative Stress

Nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy is considered a serious and increasing clinical problem without available treatment. Glycomacropeptide (GMP) is a 64-amino acid peptide derived from milk κ-casein with numerous biological activities. The aim of this study was to investigate the protective effect of GMP on NSAID enteropathy in rats. Enteropathy was induced by seven days oral indomethacin administration. Rats were orally GMP treated from seven days previous and during the establishment of the enteropathy model. Changes in metabolism, hematological and biochemical blood alterations, intestinal inflammation and oxidative damage were analyzed. Integrity barrier markers, macroscopic intestinal damage and survival rate were also evaluated. GMP treatment prevented anorexia and weight loss in animals. Furthermore, prophylaxis with GMP ameliorated the decline in hemoglobin, hematocrit, albumin and total protein levels. The treatment had no therapeutic efficacy on the decrease of occludin and mucin (MUC)-2 expression in intestinal tissue. However, GMP markedly decreased neutrophil infiltration, and CXCL1, interleukin-1β and inducible nitric oxide synthase expression. Nitric oxide production and lipid hydroperoxide level in the small intestine were also diminished. These beneficial effects were mirrored by preventing ulcer development and increasing animal survival. These results suggest that GMP may protect against NSAID enteropathy through anti-inflammatory and antioxidant properties.

Leukotriene B4 Receptor Type 2 Accelerates the Healing of Intestinal Lesions by Promoting Epithelial Cell Proliferation

Leukotriene B₄ receptor type 2 (BLT2) is a low-affinity leukotriene B₄ receptor that is highly expressed in intestinal epithelial cells. Previous studies demonstrated the protective role of BLT2 in experimentally induced colitis. However, its role in intestinal lesion repair is not fully understood. We investigated the role of BLT2 in the healing of indomethacin-induced intestinal lesions in mice. There was no significant different between wild-type (WT) and BLT2-deficient (BLT2KO) mice in terms of the development of indomethacin-induced intestinal lesions. However, healing of these lesions was significantly impaired in BLT2KO mice compared with WT mice. In contrast, transgenic mice with intestinal epithelium-specific BLT2 overexpression presented with superior ileal lesion healing relative to WT mice. An immunohistochemical study showed that the number of Ki-67-proliferative cells was markedly increased during the healing of intestinal lesions in WT mice but significantly attenuated in BLT2KO mice. Exposure of cultured mouse intestinal epithelial cells to CAY10583, a BLT2 agonist, promoted wound healing and cell proliferation in a concentration-dependent manner. Nevertheless, these responses were abolished under serum-free conditions. The CAY10583-induced proliferative effect was also negated by Go6983, a protein kinase C (PKC) inhibitor, U-73122, a phospholipase C (PLC) inhibitor, LY255283, a BLT2 antagonist, and pertussis toxin that inhibits G protein-coupled receptor signaling via G_i/o proteins. Thus, BLT2 plays an important role in intestinal wound repair. Moreover, this effect is mediated by the promotion of epithelial cell proliferation via the G_i/o protein-dependent and PLC/PKC signaling pathways. The BLT2 agonists are potential therapeutic agents for the treatment of intestinal lesions. SIGNIFICANCE STATEMENT: The healing of indomethacin-induced Crohn's disease-like intestinal lesions was impaired in mice deficient in low-affinity leukotriene B₄ receptor type 2 (BLT2). They presented with reduced epithelial cell proliferation during the healing. In contrast, healing was promoted in mice overexpressing intestinal epithelial BLT2. In cultured intestinal epithelial cells, the BLT2 agonist CAY10583 substantially accelerated wound repair by enhancing cell proliferation rather than migration. Thus, BLT2 plays an important role in the intestinal lesions via acceleration of epithelial cell proliferation.

Selective serotonin reuptake inhibitor fluvoxamine ameliorates stress- and NSAID-induced peptic ulcer possibly by involving Hsp70

Background Selective serotonin reuptake inhibitors (SSRIs) have recently become potential candidates for a new therapeutic approach to ulcer and gastric bleeding. Heat shock protein 70 (Hsp70) plays an important role in cellular resistance to nonsteroidal anti-inflammatory drugs (NSAIDs). However, there is lack of evidence that fluvoxamine recruits Hsp70 to affect stress-induced gastric ulcer. Therefore, we investigated the effect of fluvoxamine on NSAID- and stress-induced gastric ulcer and the possible involvement of Hsp70. Methods ICR mice were used in the study. Stress induction was made by the water-immersion-plus-restraint method. NSAID-induced gastric ulcer was produced by oral administration of indomethacin. Fluvoxamine was given orally 30 min before stress induction and indomethacin treatment. Results Stress and indomethacin treatment significantly increased the ulcer index and intraluminal bleeding score. Stress and indomethacin treatment also significantly increased the expression of Hsp70. Fluvoxamine significantly decreased the ulcer index and intraluminal bleeding in both ulcer models. Moreover, fluvoxamine further increased the expression of Hsp70 in the gastric tissue of stress- and indomethacin-treated mice. Conclusions Our results indicate that fluvoxamine may have a protective effect against stress- as well as NSAID-induced gastric ulcer. In addition, the present study suggests the possible involvement of Hsp70 in the amelioration of gastric ulcer by fluvoxamine.

Effects and possible mechanisms of Alpinia officinarum ethanol extract on indomethacin-induced gastric injury in rats

CONTEXT

Alpinia officinarum Hance (Zingiberoside) has a long history in treating gastrointestinal diseases, but its mechanisms of action are not yet known.

OBJECTIVE

To investigate the effects and underlying mechanisms of the ethanol extract of A. officinarum rhizomes in an indomethacin-induced gastric injury rat model.

MATERIAL AND METHODS

Indomethacin (0.3 g/kg) was orally administered to Sprague-Dawley rats to induce gastric damage; after 7 h, the rats were treated with 0.03, 0.09, or 0.18 g/kg of the plant extract, galangin (0.2 g/kg), or bismuth potassium citrate (0.08 g/kg), once a day for 6 days. Rats in the control group received an equivalent volume of vehicle solution for 6 days. Gastric damage was evaluated by gross ulcer and histological indexes. Cyclooxygenase and non-cyclooxygenase pathway proteins were quantified by western blotting and ELISA.

RESULTS

Alpinia officinarum extract ameliorated gastric injury in a dose-dependent manner, and 0.18 g/kg dose exhibited the best performance by reducing the gross ulcer (from 20.23 ± 1.38 to 1.66 ± 0.37) and histological (from 4.67 ± 1.03 to 0.33 ± 0.51) indexes, decreasing serum TNF-α level (14.17%), increasing serum VEGF level (1.58 times), increasing cyclooxygenase-1 level (1.25 times, p <  0.001) in the gastric mucosa, and reversing indomethacin-induced changes in the expression of non-cyclooxygenase pathway proteins (p <  0.05). Galangin was less effective as an antiulcer agent than the whole extract, indicating that other components also contributed to the protective effect.

CONCLUSIONS

Alpinia officinarum extract and galangin exert antiulcer effects through cyclooxygenase and non-cyclooxygenase pathways validating use of galangin as a treatment for gastric damage.

Using human iPS cell-derived enterocytes as novel in vitro model for the evaluation of human intestinal mucosal damage

OBJECTIVE AND DESIGN

The primary component in gut mucus is mucin 2 (MUC2) secreted by goblet cells. Fluctuations in MUC2 expression are considered a useful indicator for evaluating mucosal damage and protective effect of various agents using animal studies. However, there are few in vitro studies evaluating mucosal damage using MUC2 as the indicator. Hence, we attempted to establish a novel in vitro model with MUC2 as the indicator for evaluating drug-induced mucosal damage and protective effect using enterocytes derived from human iPS cells.

METHODS

Compounds were added into enterocytes derived from human iPS cells, and MUC2 mRNA and protein expression levels were evaluated. Further, the effect of compounds on membrane permeability was investigated.

RESULTS

Nonsteroidal anti-inflammatory drugs were found to decrease MUC2 mRNA expression in enterocytes, whereas mucosal protective agents increased mRNA levels. Changes in MUC2 protein expression were consistent with those of mRNA. Additionally, our results indicated that indomethacin caused mucosal damage, affecting membrane permeability of the drug. Moreover, we observed protective effect of rebamipide against the indomethacin-induced permeability increase.

CONCLUSIONS

The developed model could facilitate evaluating drug-induced mucosal damage and protective effects of various agents and could impact drug development studies regarding pharmacological efficacy and safety.

Determination of potential oxidative damage, hepatotoxicity, and cytogenotoxicity in male Wistar rats: Role of indomethacin

The present study demonstrated the indomethacin (INDO) induced oxidative stress, hepatotoxicity, and genotoxicity in male Wistar rats. Animals were orally administrated INDO at doses of 0.302 and 0.605 (mg/kg b.w.) for 2 weeks. Reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation (LPO) activities/levels were measured in the liver, kidney, and brain tissues. The aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) activities, total bilirubin (TBIL) levels, and histopathological changes were determined in the liver tissues. Micronucleus frequency (micronucleus test) and DNA damage (comet assay) tests were performed in the bone marrow cells and leukocytes, respectively. Results show that INDO treatment decreased the GSH, SOD, and CAT levels/activities and increased the LPO, ALT, AST, ALP, and TBIL activities/levels. INDO induced significant hepatic injury and micronucleus and DNA damage. Thus, the current investigations confirm the oxidative stress, hepatotoxic, and genotoxic properties of INDO in the male Wistar rats.

Combination therapy with polydeoxyribonucleotide and proton pump inhibitor enhances therapeutic effectiveness for gastric ulcer in rats

AIMS

The main action of proton pump inhibitors (PPIs) is to inhibit gastric acid secretion, and PPIs are widely used to treat gastric ulcer (GU). However, if the action of promoting gastric mucosal regeneration is added, the effectiveness of GU treatment can be enhanced. Thus, in order to improve the therapeutic effect on GU, we tried to develop combination therapy promoting regeneration in injured tissue besides suppressing gastric acid secretion.

MAIN METHODS

Polydeoxyribonucleotide (PDRN) was selected to evaluate tissue regeneration, and pantoprazole was chosen as one of the PPIs. GU was induced by oral administration of indomethacin once a day for 7 days. Rats in drug-administered groups were intraperitoneally injected with 100 μL normal saline, containing each drug at the indicated concentration, once a day for 14 days after inducing GU.

KEY FINDINGS

PDRN and PPI combination therapy potently improved tissue regeneration and inhibited production of pro-inflammatory cytokines. PDRN treatment with or without PPI increased the concentration of cyclic adenosine-3,5'-monophosphate (cAMP) and the ratio of phosphorylated cAMP response element-binding protein (p-CREB) to cAMP response element-binding protein (CREB). PDRN treatment with or without PPI also increased the expressions of vascular endothelial growth factor (VEGF) and adenosine A_2A receptor.

SIGNIFICANCE

PDRN and PPI combination therapy showed more potent therapeutic effect on GU compared to the PDRN monotherapy or PPI monotherapy. The excellent therapeutic effect of PDRN and PPI combination therapy on GU appeared by promoting regeneration of damaged tissue as well as inhibiting gastric acid secretion.

Antioxidant and anti-inflammatory activities of alpha lipoic acid protect against indomethacin-induced gastric ulcer in rats

Little is known about the role of tumor necrosis factor-alpha (TNF-α), plasminogen activator inhibitor-1 (PAI-1), and inducible nitric oxide synthase (iNOS) in the gastric ulcer and the effect of alpha lipoic acid (ALA) in their modulation. Hence, this experimental study was designed to assess the possible protective effect of ALA against indomethacin (IND)-induced gastric ulcer in rats, as well as to determine the possible underlying mechanisms with a special focus on TNF-α, PAI-1, and iNOS. Adult male rats (n = 28) were divided into four equal groups: the control group received distilled water, the vehicle group received 0.5% carboxymethylcellulose, the ulcer group received a single oral dose of IND (50 mg/kg) and the ALA-treated group received ALA (100 mg/kg) orally for 3 days before ulcer induction. Four hours after IND administration, all rats were sacrificed. The ulcer index, and gastric tissue homogenate contents of total antioxidant capacity (TAC), malondialdehyde (MDA), TNF-α, and PAI-1 were evaluated. Immunohistochemical evaluation of iNOS protein expression and histopathological examination of gastric tissue were investigated. The results revealed that ALA pretreatment significantly decreased the ulcer index, the gastric levels of MDA, TNF-α, PAI-1, and iNOS protein expression while increased the gastric levels of TAC as well as improved the histopathological appearance of gastric tissues. In conclusion, ALA ameliorated the IND-induced gastric ulceration. This could be attributed to its antioxidant and anti-inflammatory activities via suppression of TNF-α-induced elevation of both PAI-1 level and iNOS expression in the gastric tissue.

NGF protects endothelial cells from indomethacin-induced injury through activation of mitochondria and upregulation of IGF-1

BACKGROUND/AIMS

Endothelial cells (ECs) lining blood vessels are critical for delivery of oxygen and nutrients to all tissues and organs and play a crucial role in the regeneration of blood vessel following tissue injury. ECs are also major targets of injury by a variety of noxious factors [e.g., ethanol and nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, indomethacin, diclofenac], especially in gastric mucosa that has direct exposure to these agents. In this study, we investigated whether nerve growth factor (NGF) can protect gastric microvascular ECs (GECs) from injury by indomethacin (INDO) and the mechanisms involved.

METHODS

GECs were isolated from rat gastric mucosa and pre-treated with either vehicle or NGF (100ng/ml) for 30min to 4h followed by treatment with vehicle or 0.25mM INDO for 4h.

STUDIES

1) cell viability using Calcein AM live cell tracking dye, 2) mitochondrial structure and function using MitoTracker, molecular probe that stains mitochondria in live cells in a manner dependent on mitochondrial membrane potential (MMP), 3) in vitro angiogenesis - endothelial tube formation on Matrigel, 4) expression and subcellular localization of NGF receptor, TrkA, and 5) expression of IGF-1 protein.

RESULTS

Treatment with INDO reduced GEC viability and in vitro angiogenesis and induced mitochondrial injury and MMP depolarization. NGF pre-treatment protected GECs from INDO-induced injury preventing both INDO-induced MMP depolarization and reduced in vitro angiogenesis. The NGF high affinity receptor, TrkA, was localized in GECs to both cell membrane and mitochondria. NGF treatment of GECs also resulted in increased IGF-1 protein expression.

CONCLUSIONS

1) NGF protects GECs against IND-induced injury. 2) Mitochondria are major targets of both INDO-induced injury and NGF afforded protection of GECs. 3) TrkA expression in the mitochondria of GECs indicates that the protection afforded by NGF is partly mediated by its direct action on mitochondria. 4) NGF prevents MMP depolarization and increases expression of IGF-1 protein in GECs. These studies indicate that NGF may play a protective role against injury to GECs; and, that maintenance of mitochondrial structure and function is one of the mechanisms.

Gastroprotective effect and mode of action of methanol extract of Sphenodesme involucrata var. paniculata (C.B. Clarke) Munir (Lamiaceae) leaves on experimental gastric ulcer models

Sphenodesme involucrata var. paniculata (C. B. Clarke) Munir, endemic to South Asia, is used by tribal for alleviation from abdominal disorders, inflammation and body pain. However, the gastroprotective properties of this species have not yet been studied. The leaves of S. involucrata were extracted by Soxhlet extraction using different solvents successively and the extracts were analyzed for antioxidant and anti-Helicobacter pylori activities using different in vitro assays. The chemical composition of methanol extract of S. involucrata (MESi) was analysed by gas chromatography-mass spectrometry (GC-MS). The gastroprotective action of the MESi at the doses of 100, 200, and 400 mg/kg were evaluated in absolute ethanol, acidified ethanol (EtOH/HCl) and nonsteroidal anti-inflammatory drug (NSAID) induced rat experimental models. To elucidate the mode of antiulcerogenic action, the antisecretory parameters (gastric juice volume, pH, and total acidity) and the catalase (CAT) and superoxide dismutase (SOD) enzymes activity and malondialdehyde (MDA) level were evaluated in gastric ulcer tissue. Also the stomachs of the animals were subjected to histological assessment. MESi presented a high antioxidant activity in several oxidants in vitro systems (DPPH^•, ABTS^•+ and FRAP) and it demonstrated a good spectrum of inhibitory activity against H. pylori growth (MIC, 100 μg/mL). GC-MS analysis of MESi indicated the presence of twenty one compounds, among them phenol (21.84%), hexadecanoic acid (15.96%), (9E, 12E)-9, 12-octadecadienoyl chloride (11.15%) and palmitic acid-β-monoglyceride (8.80%) were found higher. MESi (100, 200 and 400 mg/kg, p.o.) produced significant reduction (p < 0.01) of lesion area in the ethanol, acidified ethanol and indomethacin-induced ulcer models. In the pylorus ligation induced ulcer model, the treatment with MESi significantly altered the gastric secretion by decreasing total gastric juice volume and gastric acidity as well as by increasing the gastric pH. MESi pre-treatment significantly (p < 0.05) restored the depleted activity of SOD, CAT enzymes and reduced MDA levels in the gastric tissue as well as the histological analysis of the stomachs of the animals showed that the MESi also prevents local action of offensive factors. Collectively, the present study results suggest that the methanol extract of S. involucrata leaves demonstrates gastroprotective action, supporting the folkloric usage of the plant to treat gastro-intestinal disturbances.

Ozonation of indomethacin: Kinetics, mechanisms and toxicity

Ozonation of a commonly used non-steroidal anti-inflammatory drug indomethacin (IM) was studied. Kinetic constants of IM with ozone and hydroxyl radicals were measured at an order of magnitude of 10⁵M^-1s^-1 and 10⁹M^-1s^-1, respectively. IM was degraded within 7min under the lowest ozone dose, but TOC removal was only 50% even under the highest ozone dose used in the experiments. Ozone rather than hydroxyl radicals was found to be the main oxidant during reaction, with a contribution rate of 80% under pH 7. Six intermediates were identified by high resolution mass spectrometer. Nitrogen atom, CC double bond and benzene ring were found to be the main reaction sites. Electrophilic attack or Criegee cyclo-addition were proved to be the most probable pathways at the first step. The formation mechanism of one of the ozone products was first proposed during the experiment, then confirmed by the density functional theory (DFT) calculation. Acetic acid, formic acid and oxalic acid were detected as small molecule organic products. The toxicity change during ozonation was measured by luminescent bacterium with results showing that the toxicity can be reduced to zero when ozone dose was high enough.

Amphiphilic poly-N-vinylpyrrolidone nanoparticles as carriers for non-steroidal, anti-inflammatory drugs: In vitro cytotoxicity and in vivo acute toxicity study

Polymeric nanoparticles were prepared from self-assembled amphiphilic N-vinylpyrrolidone polymers in aqueous media and evaluated as novel carriers of indomethacin, a non-steroidal, anti-inflammatory drug. It was determined that these nanoparticles could be created in spherical morphologies with sizes less than 100nm, narrow size distributions and high indomethacin contents(up to 35%) combined with high drug loading efficiencies(up to 95%). In cytotoxicity tests using the human embryonic stem cell derived fibroblasts (EBF-H9) and hepatocellular carcinoma cells (HepG2), the indomethacin-loaded polymeric nanoparticles showed higher cell viability compared to that of free indomethacin at the same concentration. The median LD₅₀ values, determined by the Litchfield-Wilcoxon method, were 55-70mg/kg body weight depending on the polymer molecular design in both mice and rats. Based on the acquired results, these novel amphiphilic poly-N-vinylpyrrolidone nanoparticles can be considered as potential carriers for new, highly efficient, injectable drug delivery systems for hydrophobic drugs such as indomethacin.

[MECHANISMS OF PROULCEROGENIC EFFECT OF CORTISOL AT PHARMACOLOGICAL DOSE ON THE GASTRIC MUCOSA]

In this study, we investigated the mechanisms of proulcerogenic effect of Cortisol at pharmacological dose on the gastric mucosa in rats. Cortisol (300 mg/kg, ip, single) was administered 1, 3, 5, 7 and 30 days before ulcerogenic stimulus (indomethacin, 35 mg/kg, sc). The gastric mucosa integrity, blood corticosterone, glucose levels, the body weight and the thymus and spleen weight were tested 4 h after indomethacin or at appropriate day after cortisol treatment (in rats without indomethacin). Cortisol treatment resulted in an increase in blood glucose levels with a maximum at day 3, decrease in the body weight and weight of the thymus and the spleen. A deficiency of glucocorticoids in the blood and an increase in indomethacin-induced gastric injury were observed 7 days after the cortisol pretreatment. At the same time all parameters did not differ from controls 30 days after cortisol pretreatment. The results suggest that cortisol at a pharmacological dose may cause proulcerogenic action on the gastric mucosa through a long-lasting maintenance of blood glucose levels accompanied by the signs of catabolic effect and through a deficiency of glucocorticoid production.

Indomethacin Exacerbates Oleic Acid-Induced Acute Respiratory Distress Syndrome in Adult Rats

Acute respiratory distress syndrome (ARDS) is an acute fulminant condition associated with acute lung injury and inflammation leading to hypoxemia, pulmonary edema and respiratory failure. Even though prostaglandins are inflammatory mediators, the role of prostaglandins in ARDS is still not clear. Therefore, we examined the involvement of prostaglandin in experimentally induced ARDS by using prostaglandin synthesis inhibitor, indomethacin. Experiments were conducted on anesthetized adult rats (total n=15). Cannulation of trachea, jugular vein and carotid artery was done in these rats. Recording of respiratory excursions (for respiratory frequency; RF), ECG (for heart rate; HR) and blood pressure, before and after lethal dose of oleic acid (75 μL i.v.) was done for 120 min or till death of the animals. Arterial blood sample was collected 15 min after oleic acid injection to determine PaO2/FiO2 ratio. Lungs were excised at the end of experiment for estimation of pulmonary water content. Administration of oleic acid produced progressive increase in the RF up to 45 min followed by decrease. Subsequently, the respiration stopped and all the animals died by 75 min (mean survival time = 64±8.2 min). HR and mean arterial pressure (MAP) exhibited an immediate decrease followed by an increase up to 45 min. Thereafter, the HR and MAP progressively decreased. PaO2/FiO2 ratio in this group was 182±2.6 mm Hg and pulmonary water content was significantly greater than saline control group. However in indomethacin pretreated rats, injection of oleic acid produced instantaneous decrease in RF and all the animals died within 10 min (mean survival time = 6.6±1.07 min). HR and MAP followed the same pattern as seen with RF. Pulmonary water content in indomethacin pretreated animals was also significantly greater than control group. These observations indicate that indomethacin exacerbates the OA-induced ARDS. Thus, prostaglandins play an important role in the pathophysiology of OA-induced ARDS.

Autophagy Deficiency Diminishes Indomethacin-Induced Intestinal Epithelial Cell Damage through Activation of the ERK/Nrf2/HO-1 Pathway

Nonsteroidal anti-inflammatory drugs (NSAIDs) can cause epithelial cell damage in the stomach, intestine, and colon. NSAIDs are reported to induce autophagy and apoptosis in intestinal epithelial cells; however, their role in cell damage is poorly understood. To examine the role of autophagy in cell damage, we used autophagy-related gene Atg5-conditional knockout mice, in which the Atg5 gene is only knocked out in intestinal epithelial cells. In an indomethacin (IM)-induced gastrointestinal ulcer mouse model, intestinal epithelium damage was reduced in Atg5-conditional knockout mice compared with wild-type mice. IM-induced damage in IEC6 rat intestinal epithelial cells was reduced when Atg5 was silenced (IEC6shAtg5 cells). Western blot analyses indicated that IM-induced apoptosis decreased, and the potent, oxidative stress-related extracellular signal-regulated kinase (ERK)/nuclear factor-erythroid2-like2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway was upregulated in IEC6shAtg5 cells. An experiment using a reactive oxygen species (ROS)-sensitive fluorescent dye in IEC6shAtg5 cells revealed that the amount of ROS at the baseline and the rate of increase after IM treatment were lower than in intact IEC6 cells. The mitochondrial membrane potential at the baseline and the reduction rate in IM-treated IEC6shAtg5 cells were lower than in intact IEC6 cells, indicating that autophagy deficiency increased ROS production caused by mitochondrial disturbance. Furthermore, MnTMPyP, a manganese-superoxide dismutase mimetic, significantly inhibited IM-induced autophagy and subsequent apoptosis as well as activation of the ERK/Nrf2/HO-1 pathway. These data suggest that autophagy deficiency and subsequent activation of the ERK/Nrf2/HO-1 pathway diminished IM-induced, apoptosis-mediated intestinal epithelial cell damage, and genetic analyses of single nucleotide polymorphisms in autophagy-related genes could predict NSAID-induced intestinal injury.

Optimization, physicochemical characterization and in vivo assessment of spray dried emulsion: A step toward bioavailability augmentation and gastric toxicity minimization

The limited solubility of BCS class II drugs diminishes their dissolution and thus reduces their bioavailability. Our aim in this study was to develop and optimize a spray dried emulsion containing indomethacin as a model for Class II drugs, Labrasol®/Transuctol® mixture as the oily phase, and maltodextrin as a solid carrier. The optimization was carried out using a 2(3) full factorial design based on two independent variables, the percentage of carrier and concentration of Poloxamer® 188. The effect of the studied parameters on the spray dried yield, loading efficiency and in vitro release were thoroughly investigated. Furthermore, physicochemical characterization of the optimized formulation was performed. In vivo bioavailability, ulcerogenic capability and histopathological features were assessed. The results obtained pointed out that poloxamer 188 concentration in the formulation was the predominant factor affecting the dissolution release, whereas the drug loading was driven by the carrier concentration added. Moreover, the yield demonstrated a drawback by increasing both independent variables studied. The optimized formulation presented a complete release within two minutes thus suggesting an immediate release pattern as well, the formulation revealed to be uniform spherical particles with an average size of 7.5μm entrapping the drug in its molecular state as demonstrated by the DSC and FTIR studies. The in vivo evaluation, demonstrated a 10-fold enhancement in bioavailability of the optimized formulation, with absence of ulcerogenic side effect compared to the marketed product. The results provided an evidence for the significance of spray dried emulsion as a leading strategy for improving the solubility and enhancing the bioavailability of class II drugs.

Beneficial effect of an omega-6 PUFA-rich diet in non-steroidal anti-inflammatory drug-induced mucosal damage in the murine small intestine

AIM: To investigate the effect of a fat rich diet on non-steroidal anti-inflammatory drug (NSAID)-induced mucosal damage in the murine small intestine.

METHODS: C57BL6 mice were fed 4 types of diets with or without indomethacin. One group was fed standard laboratory chow. The other groups were fed a fat diet consisting of 8% w/w fat, beef tallow (rich in SFA), fish oil, (rich in omega-3 PUFA), or safflower oil (rich in omega-6 PUFA). Indomethacin (3 mg/kg) was injected intraperitoneally from day 8 to day 10. On day 11, intestines and adhesions to submucosal microvessels were examined.

RESULTS: In the indomethacin-treated groups, mucosal damage was exacerbated by diets containing beef tallow and fish oil, and was accompanied by leukocyte infiltration (P < 0.05). The mucosal damage induced by indomethacin was significantly lower in mice fed the safflower oil diet than in mice fed the beef tallow or fish oil diet (P < 0.05). Indomethacin increased monocyte and platelet migration to the intestinal mucosa, whereas safflower oil significantly decreased monocyte and platelet recruitment (P < 0.05).

CONCLUSION: A diet rich in SFA and omega-3 PUFA exacerbated NSAID-induced small intestinal damage via increased leukocyte infiltration. Importantly, a diet rich in omega-6-PUFA did not aggravate inflammation as monocyte migration was blocked.

Establishment of a rapid drug screening system based on embryonic stem cells

Embryonic stem (ES) cells have the capacity for self-renewal and differentiation into three germ layers following formation of embryonic bodies (EB). To investigate toxicity of pharmaceutical compounds, five toxic chemicals, indomethacin, dexamethasone, hydroxyurea, 5-fluorouracil, and cytosine arabinoside were applied in mouse ES cells during formation of EBs. Using microscopic evaluation, the size of EBs was reduced in a dose-dependent manner by treatment with pharmaceutical chemicals. While apoptosis-related proteins, cleaved caspase-3 and PARP, were decreased in compound-exposed EBs, necrosis-related protein (Hmgb1) was present in culture media of EBs, indicating that detection of Hmgb1 can result in activation of necrosis by pharmaceutical compounds. While pharmaceutical compounds impaired the differentiation of mES cells linked with spontaneous apoptotic cell death, it was determined that cytotoxic cell damage is necrosis-dependent in mES cells. In addition, an apoptotic transcript (Noxa mRNA) in toxicant-exposed EBs was decreased in parallel with apoptosis-related proteins. Following impairment of apoptosis, differentiation-related markers including un-differentiation (Sox2), endoderm (Hnf4), mesoderm (Bmp4), and ectoderm (Pax6) also fluctuated by treatment with pharmaceutical compounds. Taken together, the data imply that exposure to pharmaceutical compounds results in increased cell death hindering the spontaneous apoptosis of cells to undergo differentiation. Using both characteristics of ES cells like self-renewal or cellular pluripotency and potentials of ES cells for evaluation in toxicity of various compounds, the current study was conducted for establishment of a novel drug screening system beyond hidden virtues of the well-known chemicals.

[Metyrapone effect on gastroprotective action of corticotropin-releasing factor administered centrally against indomethacin-induced gastric injury]

In the present study, we investigated whether corticotropin-releasing factor (CRF) injected into the brain induces protection against indomethacin-caused gastric injury and the role of glucocorticoids in the protection. Gastric injury was caused by indomethacin (35 mg/kg, s.c.) in preliminary (24 h) fasted rats. CRF (10 microgram/rat, i.c.v.) was injected 30 min before administration of indomethacin. The participation of glucocorticoids was studied by metyrapone pretreatment (30 mg/kg, i.p., 30 min before CRF). Pretreatment by metyrapone, the inhibitor of glucocorticoid synthesis was the most suitable approach because of a short-lasting inhibiting effect of the drug. Metyrapone pretreatment allowed us to prevent the acute corticosterone response to CRF and avoid the lasting effects of glucocorticoid deficiency. Intracerebroventricular injection of CRF caused fast increase in plasma corticosterone levels and significantly suppressed the occurrence of gastric erosion induced by indomethacin. Metyrapone administration prevented CRF-induced corticosterone rise and significantly attenuated the protective effect of CRF on the gastric mucosa against indomethacin-produced injury. The results suggest that CRF injected into the brain may induce protection against indomethacin-caused gastric injury through the participation of glucocorticoids.

Antiulcer activity of the ethanolic extract and ethyl acetate fraction of the leaves of Markhamia tomentosa in rats

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Markhamia tomentosa (Benth.) K. Schum. Ex Engl. (Bignoniaceae) are used traditionally in the treatment of skin afflictions, sores, ulcers and inflammation. The aim of the study was to investigate the antiulcer activity of the crude ethanolic extract from the leaves of Markhamia tomentosa, determine the active fraction(s) of the extract and identify the chemical constituents in the active fraction by LC-MS.

MATERIALS AND METHODS

The antiulcer activity of the crude extract (50, 100 and 150mg/kg, p.o.) was evaluated in ethanol and indomethacin-induced models while the solvent fractions (150mg/kg) were screened using ethanol-induced gastric lesions in rats. Furthermore, anti-ulcer activity of the active fraction (50, 100 and 150mg/kg, p.o.) was performed using indomethacin and pylorus ligation models. Parameters such as gastric volume, pH and acidity were determined in the pylorus ligation model. LC-ESI-MS analysis was used to identify the components in the active fraction.

RESULTS

The extract at the dose of 50, 100 and 150mg/kg caused a significant (p<0.05) dose-dependent inhibition of ulcer in the ethanol and indomethacin-induced ulcer models, respectively. The ethyl acetate (EtOAc) fraction showed the most potent antiulcer activity from all the fractions tested. This fraction produced 72% and 92% inhibition of indomethacin and pylorus-induced ulcer at a dose of 150mg/kg respectively. Acteoside, luteolin, luteolin-7-rutinoside, Luteolin-3',7-di-O-glucoside, carnosol, dilapachone, tormentic acid, oxo-pomolic acid and ajugol were detected in the EtOAc fraction.

CONCLUSION

Our data provide a rational base for the folkloric use of Markhamia tormentosa in the treatment of ulcers.

Specific changes of gut commensal microbiota and TLRs during indomethacin-induced acute intestinal inflammation in rats

BACKGROUND AND AIMS

Gut microbiota is a contributing factor in the development and maintenance of intestinal inflammation, although precise cause-effect relationships have not been established. We assessed spontaneous changes of gut commensal microbiota and toll-like receptors (TLRs)-mediated host-bacterial interactions in a model of indomethacin-induced acute enteritis in rats.

METHODS

Male Spague-Dawley rats, maintained under conventional conditions, were used. Enteritis was induced by systemic indomethacin administration. During the acute phase of inflammation, animals were euthanized and ileal and ceco-colonic changes evaluated. Inflammation was assessed through disease activity parameters (clinical signs, macroscopic/microscopic scores and tissue levels of inflammatory markers). Microbiota (ileal and ceco-colonic) was characterized using fluorescent in situ hybridization (FISH) and analysis of 16s rDNA polymorphism. Host-bacterial interactions were assessed evaluating the ratio of bacterial adherence to the intestinal wall (FISH) and expression of TLRs 2 and 4 (RT-PCR).

RESULTS

After indomethacin, disease activity parameters increased, suggesting an active inflammation. Total bacterial counts were similar in vehicle- or indomethacin-treated animals. However, during inflammation the relative composition of the microbiota was altered. This dysbiotic state was characterized by an increase in the counts of Bacteroides spp., Enterobacteriaceae (in ileum and cecum-colon) and Clostridium spp. (in ileum). Bacterial wall adherence significantly increased during inflammation. In animals with enteritis, TLR-2 and -4 were up-regulated both in the ileum and the ceco-colonic region.

CONCLUSIONS

Gut inflammation implies qualitative changes in GCM, with simultaneous alterations in host-bacterial interactions. These observations further support a potential role for gut microbiota in the pathophysiology of intestinal inflammation.

Dipeptidyl peptidase IV inhibition prevents the formation and promotes the healing of indomethacin-induced intestinal ulcers in rats

BACKGROUNDS AND AIMS

We studied the intestinotrophic hormone glucagon-like peptide-2 (GLP-2) as a possible therapy for non-steroidal anti-inflammatory drug (NSAID)-induced intestinal ulcers. Luminal nutrients release endogenous GLP-2 from enteroendocrine L cells. Since GLP-2 is degraded by dipeptidyl peptidase IV (DPPIV), we hypothesized that DPPIV inhibition combined with luminal administration of nutrients potentiates the effects of endogenous GLP-2 on intestinal injury.

METHODS

Intestinal injury was induced by indomethacin (10 mg/kg, sc) in fed rats. The long-acting DPPIV inhibitor K579 was given intragastrically (ig) or intraperitoneally (ip) before or after indomethacin treatment. L-Alanine (L-Ala) and inosine 5'-monophosphate (IMP) were co-administered ig after the treatment.

RESULTS

Indomethacin treatment induced intestinal ulcers that gradually healed after treatment. Pretreatment with ig or ip K579 given at 1 mg/kg reduced total ulcer length, whereas K579 at 3 mg/kg had no effect. Exogenous GLP-2 also reduced intestinal ulcers. The preventive effect of K579 was dose-dependently inhibited by a GLP-2 receptor antagonist. Daily treatment with K579 (1 mg/kg), GLP-2, or L-Ala + IMP after indomethacin treatment reduced total ulcer length. Co-administration (ig) of K579 and L-Ala + IMP further accelerated intestinal ulcer healing.

CONCLUSION

DPPIV inhibition and exogenous GLP-2 prevented the formation and promoted the healing of indomethacin-induced intestinal ulcers, although high-dose DPPIV inhibition reversed the preventive effect. Umami receptor agonists also enhanced the healing effects of the DPPIV inhibitor. The combination of DPPIV inhibition and luminal nutrient-induced GLP-2 release may be a useful therapeutic tool for the treatment of NSAIDs-induced intestinal ulcers.

Anti-inflammatory and gastroprotective activities of the aqueous extract of Micromeria fruticosa (L.) Druce ssp Serpyllifolia in mice

Micromeria fruticosa is used widely in many Mediterranean regions for various inflammatory conditions. The aim of this work was to assess the anti-inflammatory and gastroprotective activities of the aqueous extract of Micromeria fruticosa. The aqueous extract of Micromeria fruticosa was tested orally in mice at doses of 50, 100 and 200 mg/kg in carrageenan-induced paw edema, vascular permeability, myeloperoxidase activity (MPO) and indomethacin-induced gastric ulceration. In the paw edema model, the extract at dose of 200 mg/ kg, exhibited a significant anti-inflammatory effect, while the extract at 100 and 200 mg/kg reduced significantly the vascular permeability and MPO activity in a dose dependant manner. Oral pretreatment of the aqueous extract reduced significantly the development of gastric lesions induced by indomethacin at dose of 200 mg/kg only. Results suggest that the aqueous extract of Micromeria fruticosa has both anti-inflammatory as well as, gastroprotective activities. Thus it could be used as an alternative or supplementary herbal remedy for the treatment of inflammatory diseases especially when combined with strong anti-inflammatory medications that have ulcerogenic side effects such as NSAIDs.

Prostaglandins, masculinization and its disorders: effects of fetal exposure of the rat to the cyclooxygenase inhibitor- indomethacin

Recent studies have established that masculinization of the male reproductive tract is programmed by androgens in a critical fetal ‘masculinization programming window’ (MPW). What is peculiar to androgen action during this period is, however, unknown. Studies from 20 years ago in mice implicated prostaglandin (PG)-mediation of androgen-induced masculinization, but this has never been followed up. We therefore investigated if PGs might mediate androgen effects in the MPW by exposing pregnant rats to indomethacin (which blocks PG production by inhibiting cyclooxygenase activity) during this period and then examining if androgen production or action (masculinization) was affected.

Pregnant rats were treated with indomethacin (0.8 mg/kg/day; e15.5–e18.5) to encompass the MPW. Indomethacin exposure decreased fetal bodyweight (e21.5), testis weight (e21.5) and testicular PGE₂ (e17.5, e21.5), but had no effect on intratesticular testosterone (ITT; e17.5) or anogenital index (AGI; e21.5). Postnatally, AGI, testis weight and blood testosterone were unaffected by indomethacin exposure and no cryptorchidism or hypospadias occurred. Penis length was normal in indomethacin-exposed animals at Pnd25 but was reduced by 26% (p<0.001) in adulthood, an effect that is unexplained.

Our results demonstrate that indomethacin can effectively decrease intra-testicular PGE₂ level. However, the resulting male phenotype does not support a role for PGs in mediating androgen-induced masculinization during the MPW in rats. The contrast with previous mouse studies is unexplained but may reflect a species difference.