Role of NRF2 in protection of the gastrointestinal tract against oxidative stress

Enhanced upregulation of SIRT1 via pioglitazone and ligustrazine confers protection against ethanol-induced gastric ulcer in rats

Gastric ulcer is a disturbing disease that impacts many people worldwide. Pioglitazone (Piog), a thiazolidinedione, and ligustrazine (Ligu), a natural component of Ligusticum chuanxiong possess gastroprotective properties. However, the underlying mechanism is not well elucidated. The present study aimed to investigate the gastroprotective effects of Piog (15 mg/kg, p.o.), Ligu (15 mg/kg, p.o.), and their combination against ethanol-induced gastric ulcer in rats. Omeprazole (10 mg/kg) was used as a standard. Pre-treatment for 7 days with Piog, Ligu, and (Piog+Ligu) effectively alleviated ethanol-predisposed oxidative stress and inflammation through restoring HO-1, GSH, and SOD tissue levels and decreasing elevated MDA, TNF-α, ICAM, I-NOS, and IL-1β contents. Moreover, Piog, Ligu, and (Piog+Ligu) markedly inhibited the ethanol-induced increase of gastric NF-KB and BAX. In contrast, this pre-treatment regimen significantly accelerated protein expression of SIRT1, Nrf2, and Bcl-2, along with autophagic proteins, ATG5 and Beclin. Interestingly, macroscopic, histopathological examination and mucin content were in harmony with previous results, where pre-treatment with Piog, Ligu, and (Piog+Ligu) showed a declined mucosal injury as evidenced by the remarkable decrease of the ulcer area percentage by 62.3%, 38.7%, and 91.2%, respectively, compared to the ethanol-ulcerated group. In conclusion, Piog and Ligu exhibited remarkable gastroprotective properties. Our study was the first to show that Piog, Ligu, and (Piog+Ligu) ameliorated oxidative stress, inflammation, and apoptosis and accelerated the autophagic process via the upregulation of the upstream SIRT1 protein. It is worth mentioning that future studies are needed to pave the way for the clinical use of Piog and Ligu as gastro-protective agents.

Pinocembrin's protective effect against acute pancreatitis in a rat model: The correlation between TLR4/NF-κB/NLRP3 and miR-34a-5p/SIRT1/Nrf2/HO-1 pathways

BACKGROUND

Acute pancreatitis (APS) is a prevalent acute pancreatic inflammation, where oxidative stress, inflammatory signaling pathways, and apoptosis activation contribute to pancreatic injury.

METHODS

Pinocembrin, the predominant flavonoid in propolis, was explored for its likely shielding effect against APS provoked by two intraperitoneal doses of L-arginine (250 mg / 100 g) in a rat model.

RESULTS

Pinocembrin ameliorated the histological and immunohistochemical changes in pancreatic tissues and lowered the activities of pancreatic amylase and lipase that were markedly elevated with L-arginine administration. Moreover, pinocembrin reinstated the oxidant/antioxidant equilibrium, which was perturbed by L-arginine, and boosted the pancreatic levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). Pinocembrin markedly reduced the elevation in serum C-reactive protein (CRP) level induced by L-arginine. Additionally, it decreased the expression of high motility group box protein 1 (HMGB1), toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and NOD-like receptor (NLR) Family Pyrin Domain Containing 3 (NLRP3) inflammasome in the pancreas. Furthermore, it also reduced myeloperoxidase (MPO) activity. Pinocembrin markedly downregulated miR-34a-5p expression and upregulated the protein levels of peroxisome proliferator-activated receptor alpha (PPAR-α) and Sirtuin 1 (SIRT1) and the gene expression level of the inhibitor protein of NF-κB (IκB-α), along with normalizing the Bax/Bcl-2 ratio.

CONCLUSIONS

Pinocembrin notably improved L-arginine-induced APS by its antioxidant, anti-inflammatory, and anti-apoptotic activities. Pinocembrin exhibited a protective role in APS by suppressing inflammatory signaling via the TLR4/NF-κB/NLRP3 pathway and enhancing cytoprotective signaling via the miR-34a-5p/SIRT1/Nrf2/HO-1 pathway.

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.

Gastroprotective Effect of Quercus infectoria Olivier Galls on Ethanol-Induced Gastritis in Rats

One of the common inflammatory disorders that substantially affects the stomach and its mucosa is gastritis. It can be induced by non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, alcohol, Helicobacter pylori infection, and stress. These factors affect cellular regeneration, mucus production, and bicarbonate secretion, resulting finally in inflammation and ulceration. Ethanol-induced gastritis is one of the commonly used models for studying the pathology of gastritis and investigating the effect of drugs in managing the disease. Several drugs, such as proton pump inhibitors (PPIs), are available to control and correct the pathological signs of gastritis; however, the side effects of such drugs represent an obstacle to their applications in many cases. Quercus infectoria (QI) Olivier galls are formed as a pathological response to wasp insults to the tree. They are rich in several bioactive molecules, e.g., gallotannins that have been shown to be effective in several inflammatory conditions due to their antioxidant and anti-inflammatory potentials. In this study, we aimed to evaluate the therapeutic potential of QI gall extract (QIGE) in treating ethanol-induced gastritis in rats. To test this, 20 adult male Swiss rats were divided into four groups: healthy control, ethanol-treated (80% in water, 5 ml/kg, per oral gavage), ethanol + omeprazole (20 mg/kg, per oral gavage), and ethanol + QIGE (300 mg/kg, per oral gavage). QIGE was administered for seven days before ethanol administration, which took place three hours after the last QIGE dose. Three hours after ethanol intake, animals were euthanized, gastric content was collected, and stomach tissue was examined for macroscopic changes and then fixed to be further utilized for histological assessment by hematoxylin and eosin (H&E), periodic acid-Schiff (PAS), and Masson's trichrome staining. Ethanol treatment significantly decreased gastric pH and increased gastric acidity compared to healthy control. It also induced clear morphological and histological damage and ulceration, depleted mucus on the gastric epithelium, and induced edema and collagen deposition in gastric submucosa. The QIGE treatment ameliorated the changes in gastric pH and total acidity. It also protected stomach tissue from ethanol-induced ulceration, histopathological changes, edema, and collagen deposition. The protective effects of QIGE were comparable to those of omeprazole. In conclusion, QI gall extract possesses a promising gastroprotective effect against ethanol-induced gastritis.

Natural xanthones as modulators of the Nrf2/ARE signaling pathway and potential gastroprotective agents

Oxidative stress is implicated in the initiation, pathogenesis, and progression of various gastric inflammatory diseases (GID). The prevalence of these diseases remains a concern along with the increasing risks of adverse effects in current clinical interventions. Hence, new gastroprotective agents capable of inhibiting oxidative stress by modulating cellular defense systems such as the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway are critically needed to address these issues. A candidate to solve the present issue is xanthone, a natural compound that reportedly exerts gastroprotective effects via antioxidant, anti-inflammatory, and cytoprotective mechanisms. Moreover, xanthone derivatives were shown to modulate the Nrf2/ARE signaling pathway to counter oxidative stress in both in vitro and in vivo models. Thirteen natural xanthones have demonstrated the ability to modulate the Nrf2/ARE signaling pathway and have high potential as lead compounds for GID as indicated by their in vivo gastroprotective action-particularly mangiferin (2), α-mangostin (3), and γ-mangostin (4). Further studies on these compounds are recommended to validate the Nrf2 modulatory ability in relation to their gastroprotective action.

Apium extract alleviates indomethacin-induced gastric ulcers in rats via modulating the VEGF and IK-κB/NF-κB p65 signaling pathway: insights from in silico and in vivo investigations

BACKGROUND

Gastric ulcers represent a worldwide health problem, characterized by erosions that affect the mucous membrane of the stomach and may even reach the muscular layer, leading to serious complications. Numerous natural products have been assessed as anti-ulcerogenic agents, and have been considered as new approaches for treatment or prevention of gastric ulcers. The present research investigated the preventive benefits of Apium graveolens L. (Apiaceae), known as celery, seed extract towards indomethacin-induced ulceration of the stomach in rats.

METHODS

Metabolomic profiling, employing liquid chromatography coupled to high-resolution electrospray ionization mass spectrometry (LC-HR-ESI-MS), was implemented with the aim of investigating the chemical profile of the seeds. Histopathological analysis of gastric tissues, as well as assessment of numerous inflammatory cytokines and oxidative stress indicators, confirmed the in vivo evaluation.

RESULTS

The prior treatment with A. graveolens seed extract resulted in a substantial reduction in the ulcer index when compared to the indomethacin group, indicating an improvement in stomach mucosal injury. Moreover, the gastroprotective effect was demonstrated through examination of the oxidative stress biomarkers which was significantly attenuated upon pre-treatment with A. graveolens seed extract. Vascular endothelial growth factor (VEGF), a fundamental angiogenic factor that stimulates angiogenesis, was markedly inhibited by indomethacin. A. graveolens seed extract restored this diminished level of VEGF. The dramatic reductions in NF-κB protein levels indicate a considerable attenuation of the indomethacin-induced IKκB/NF-κB p65 signaling cascade. These activities were also correlated to the tentatively featured secondary metabolites including, phenolic acids, coumarins and flavonoids, previously evidenced to exert potent anti-inflammatory and antioxidant activities. According to our network pharmacology study, the identified metabolites annotated 379 unique genes, among which only 17 genes were related to gastric ulcer. The PTGS2, MMP2 and PTGS1 were the top annotated genes related to gastric ulcer. The top biological pathway was the VEGF signaling pathway.

CONCLUSION

A. graveolens seed extract possesses significant anti-ulcer activity, similar to famotidine, against gastric lesions induced by indomethacin in rats. It is worth highlighting that the extract overcomes the negative effects of conventional chemical anti-secretory drugs because it does not lower stomach acidity.

Ipomoea carnea mitigates ethanol-induced ulcers in irradiated rats via Nrf2/HO-1 pathway: an in vivo and in silico study

The aim of this study was to investigate the potential of Ipomoea carnea flower methanolic extract (ICME) as a natural gastroprotective therapy against ethanol-induced gastric ulcers, particularly in individuals exposed to ionizing radiation (IR). The study focused on the Nrf2/HO-1 signaling pathway, which plays a crucial role in protecting the gastrointestinal mucosa from oxidative stress and inflammation. Male Wistar rats were divided into nine groups, the control group received distilled water orally for one week, while other groups were treated with ethanol to induce stomach ulcers, IR exposure, omeprazole, and different doses of ICME in combination with ethanol and/or IR. The study conducted comprehensive analyses, including LC-HRESI-MS/MS, to characterize the phenolic contents of ICME. Additionally, the Nrf2/HO-1 pathway, oxidative stress parameters, gastric pH, and histopathological changes were examined. The results showed that rats treated with IR and/or ethanol exhibited histopathological alterations, increased lipid peroxidation, decreased antioxidant enzyme activity, and reduced expression levels of Nrf2 and HO-1. However, pretreatment with ICME significantly improved these parameters. Phytochemical analysis identified 39 compounds in ICME, with flavonoids, hydroxybenzoic acids, and fatty acids as the predominant compounds. Virtual screening and molecular dynamics simulations suggested that ICME may protect against gastric ulceration by inhibiting oxidative stress and inflammatory mediators. In conclusion, this study demonstrates the potential of ICME as a natural gastroprotective therapy for preventing gastric ulcers. These findings contribute to the development of novel interventions for gastrointestinal disorders using natural plant extracts particularly in individuals with a history of radiation exposure.

The enteroprotective effect of nifuroxazide against methotrexate-induced intestinal injury involves co-activation of PPAR-γ, SIRT1, Nrf2, and suppression of NF-κB and JAK1/STAT3 signals

Methotrexate (MTX) has long manifested therapeutic efficacy in several neoplastic and autoimmune disorders. However, MTX-associated intestinal toxicity restricts the continuation of treatment. Nifuroxazide (NIF) is an oral antibiotic approved for gastrointestinal infections as an effective antidiarrheal agent with a high safety profile. The current study was designed to explore the potential efficacy of NIF in alleviating intestinal toxicity associated with MTX chemotherapy with the elucidation of the proposed molecular mechanisms. Rats were administered NIF (50 mg/kg; p.o.) for ten days. On day five, a single i.p. injection of MTX (20 mg/kg) was given to induce intestinal intoxication. At the end of the experiment, duodenal tissue samples were isolated for biochemical, Western blotting, immunohistochemical (IHC), and histopathological analysis via H&E, PSA, and Alcian blue stains. NIF showed antioxidant enteroprotective effects against MTX intestinal intoxication through enhanced expression of the redox-sensitive signals of PPAR-γ, SIRT1, and Nrf2 estimated by IHC. Moreover, NIF down-regulated the pro-inflammatory cytokines (TNF-α, IL-1β, IL-6), NF-κB protein expression, and the phosphorylation of JAK1/STAT3 proteins, leading to mitigation of intestinal inflammation. In accordance, the histological investigation revealed that NIF ameliorated the intestinal pathological changes, preserved the goblet cells, and reduced the inflammatory cells infiltration. Therefore, NIF could be a promising candidate for adjunctive therapy with MTX to mitigate the associated intestinal injury and increase its tolerability.

Food Polyphenols as Preventive Medicine

Reactive oxygen species (ROS) are the initiators in foods and in the stomach of oxidized dietary lipids, proteins, and lipid-oxidation end-products (ALEs), inducing in humans the development of several chronic diseases and cancer. Epidemiological, human clinical and animal studies supported the role of dietary polyphenols and derivatives in prevention of development of such chronic diseases. There is much evidence that polyphenols/derivatives at the right timing and concentration, which is critical, acts mostly in the aerobic stomach and generally in the gastrointestinal tract as reducing agents, scavengers of free radicals, trappers of reactive carbonyls, modulators of enzyme activity, generators of beneficial gut microbiota and effectors of cellular signaling. In the blood system, at low concentration, they act as generators of electrophiles and low concentration of H2O2, acting mostly as cellular signaling, activating the PI3K/Akt-mediated Nrf2/eNOS pathways and inhibiting the inflammatory transcription factor NF-κB, inducing the cells, organs and organism for eustress, adaptation and surviving.

Promising effect of Geranium robertianum L. leaves and Aloe vera gel powder on Aspirin®-induced gastric ulcers in Wistar rats: anxiolytic behavioural effect, antioxidant activity, and protective pathways

BACKGROUND

Many drugs have been restricted in the treatment of gastric ulcers (GU). So, herbal medicines are now in great demand for their better cultural acceptability, compatibility, and minimal side effects. Therefore, our study aimed to assess the protective efficacy of Aloe vera gel and Geranium robertianum extracts against Aspirin®-induced GU in Wistar rats.

METHODS

Antioxidant activity and chemical composition of both herbs were analysed. Then, we divided forty female Wistar rats into five groups: a negative control group, a positive control group of Aspirin®-induced GU, and pretreated groups with Aloe Vera, geranium, and Famotidine (reference drug). The locomotor disability, anxiety-like behaviour, and ultrasonography were assessed. Ultimately, scarification of animals to determine gastric juice pH and ulcer index. Then the collection of stomach and liver for histopathological and immunohistochemical examinations, besides tracing the oxidative stress biomarkers and related genes.

RESULTS

High content of polyphenols was revealed in both extracts. The pretreatment with Aloe vera gel and geranium showed significant antioxidant activities with free radical scavenging and ferric-reducing power (FRAP). Moreover, they improved the stomach architecture and alleviated anxiety-like behaviour and motor deficits. They significantly reduced the expression of proinflammatory cytokine (TNF-α), inflammatory, and oxidative stress genes (NF-KB, HO-1, Nrf-2) while increasing the Keap-1 in gastric mucosa.

CONCLUSION

Data presented a significant protective effect of Aloe vera gel and geranium against Aspirin®-induced GU; they reduced gastric mucosal injury with potential anxiolytic effects through their anti-inflammatory and antioxidant properties. Therefore, they may be considered promising agents for preventing or treating gastric ulceration.

Effects of oxidative stress regulation in inflammation-associated gastric cancer progression treated using traditional Chinese medicines: A review

Gastric cancer (GC) is a global public health concern that poses a serious threat to human health owing to its high morbidity and mortality rates. Due to the lack of specificity of symptoms, patients with GC tend to be diagnosed at an advanced stage with poor prognosis. Therefore, the development of new treatment methods is particularly urgent. Chronic atrophic gastritis (CAG), a precancerous GC lesion, plays a key role in its occurrence and development. Oxidative stress has been identified as an important factor driving the development and progression of the pathological processes of CAG and GC. Therefore, regulating oxidative stress pathways can not only intervene in CAG development but also prevent the occurrence and metastasis of GC and improve the prognosis of GC patients. In this study, PubMed, CNKI, and Web of Science were used to search for a large number of relevant studies. The review results suggested that the active ingredients of traditional Chinese medicine (TCM) and TCM prescriptions could target and improve inflammation, pathological status, metastasis, and invasion of tumor cells, providing a potential new supplement for the treatment of CAG and GC.

The effects of alpha-pinene on the Nrf2-HO1 signaling pathway in gastric damage in rats

BACKGROUND

Alpha-pinene (α-pinene) is a monoterpene with gastroprotective activity. We evaluated the gastroprotective effect of α-pinene in the gastric damage model with ethanol.

METHODS

We evaluated the macroscopic evaluation of the stomach cavity, alteration in pH, mRNA expression of nuclear factor erythroid 2- related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), total antioxidant capacity (TAC) levels, and histopathological changes.

RESULTS

Pretreatment with α-pinene (10, 50 and 100 mg/kg i.p.) before oral administration of ethanol reduced gastric mucosal damage by increasing the percentage of ulcer inhibition. Alpha-pinene also increased gastric pH similar to omeprazole. In addition, the histopathological examination showed that in the groups pretreated with α-pinene 50 and 100 mg/kg, and omeprazole20 mg/kg, the lesions were less than the control group. Moreover, α- pinene 10, 50, 100, and omeprazole 20 mg/kg upregulated the NRF2 and HO1.

CONCLUSIONS

Our results show that pretreatment with α-pinene is effective in reducing ethanol-induced gastric damage through regulation of Nrf2/HO-1.

Cornu aspersum mucin attenuates indomethacins-induced gastric ulcers in mice via alleviating oxidative stress and inflammation

In the past three decades, a significant progress has been made in the prevention and treatment of gastric ulcers. The incidence of the disease has decreased, but gastric ulcer is still a medical problem. Currently, the available drugs for gastric ulcer treatment have many side effects; therefore, searching for new and safe therapeutic agents is mandatory. The present study aims to investigate the gastroprotective potential of Cornu aspersum (C. aspersum) mucin against gastric ulcers, and the mechanisms related to oxidative stress and inflammation. C. aspersum mucin was collected from 50 snails. The characteristics of C. aspersum mucin (chemical and microbiological) were evaluated. Mice were pretreated with famotidine and C. aspersum mucin (7.5 and 15 ml/kg b.w.) for 5 days, and then gastric ulcers were induced by indomethacin. Macroscopic examination, biochemical estimations, and Quantitative real-time PCR were carried out. Also, histopathological and immunohistopathological examinations were evaluated. We found that the high dose of the mucin significantly decreased the gastric mucosal malondialdehyde (MDA) and nitric oxide (NO) contents as well as interleukin 1β (IL-1β) and nuclear factor kappa β (NF-ҡB) expression, and inducible nitric oxide synthase (iNOS) immunostaining. It also increased the gastric mucosal GSH and catalase contents as well as hemoxygenase-1 (HO-1) and nuclear factor-erythroid 2-related factor 2 (Nrf2) expressions with regressions in gastric mucosal lesions. In conclusion, C. aspersum mucin could be a potential therapeutic candidate to protect against gastric ulceration.

Advances in health-promoting effects of natural polysaccharides: Regulation on Nrf2 antioxidant pathway

Natural polysaccharides (NPs) possess numerous health-promoting effects, such as liver protection, kidney protection, lung protection, neuroprotection, cardioprotection, gastrointestinal protection, anti-oxidation, anti-diabetic, and anti-aging. Nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant pathway is an important endogenous antioxidant pathway, which plays crucial roles in maintaining human health as its protection against oxidative stress. Accumulating evidence suggested that Nrf2 antioxidant pathway might be one of key regulatory targets for the health-promoting effects of NPs. However, the information concerning regulation of NPs on Nrf2 antioxidant pathway is scattered, and NPs show different regulatory behaviors in their different health-promoting processes. Therefore, in this article, structural features of NPs having regulation on Nrf2 antioxidant pathway are overviewed. Moreover, regulatory effects of NPs on this pathway for health-promoting effects are summarized. Furthermore, structure-activity relationship of NPs for health-promoting effects by regulating the pathway is preliminarily discussed. Otherwise, the prospects on future work for regulation of NPs on this pathway are proposed. This review is beneficial to well-understanding of underlying mechanisms for health-promoting effects of NPs from the view angle of Nrf2 antioxidant pathway, and provides a theoretical basis for the development and utilization of NPs in promoting human health.

Insights into diet-associated oxidative pathomechanisms in inflammatory bowel disease and protective effects of functional amino acids

There has been a substantial rise in the incidence and prevalence of clinical patients presenting with inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis. Accumulating evidence has corroborated the view that dietary factors (particularly diets with high levels of saturated fat or sugar) are involved in the development and progression of IBD, which is predominately associated with changes in the composition of the gut microbiota and an increase in the generation of reactive oxygen species. Notably, the ecological imbalance of the gut microbiome exacerbates oxidative stress and inflammatory responses, leading to perturbations of the intestinal redox balance and immunity, as well as mucosal integrity. Recent findings have revealed that functional amino acids, including L-glutamine, glycine, L-arginine, L-histidine, L-tryptophan, and hydroxyproline, are effectively implicated in the maintenance of intestinal redox and immune homeostasis. These amino acids and their metabolites have oxygen free-radical scavenging and inflammation-relieving properties, and they participate in modulation of the microbial community and the metabolites in the gut. The principal focus of this article is a review of recent advances in the oxidative pathomechanisms of IBD development and progression in relation to dietary factors, with a particular emphasis on the redox and signal transduction mechanisms of host cells in response to unbalanced diets and enterobacteria. In addition, an update on current understanding of the protective effects of functional amino acids against IBD, together with the underlying mechanisms for this protection, have been provided.

Lactoferrin mitigates ethanol-induced gastric ulcer via modulation of ROS/ICAM-1/Nrf2 signaling pathway in Wistar rats

Objectives

We aimed to investigate the gastroprotective effect of lactoferrin (LF; 100 & 300 mg/kg) in male Wistar rats versus gastric ulcers induced by 96% ethanol.

Materials and Methods

Rats were randomly allocated into 4 groups: control, ethanol, ethanol+LF100, and ethanol+LF300. LF100 & 300 were given 15 days before ulcer induction. At the end of the experiment, the gastric mucosa was examined macroscopically and microscopically.

Results

The ethanol group showed damage and degeneration of the stomach mucosa in addition to elevation of oxidative and inflammatory biomarkers. LF showed explicit healing of the gastric mucosal damage. LF reduced gastric malondialdehyde (MDA), tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), myeloperoxidase (MPO), and intracellular adhesion molecule-1 (ICAM-1). On the other hand, LF elevated the depleted reduced glutathione (GSH) and Nuclear factor-erythroid factor 2 (Nrf2).

Conclusion

Our current study is the first to study the antiulcer effect of LF via its potential modulatory effects on the ROS/ICAM-1/Nrf2 signaling pathway. Moreover, we concluded that pretreatment with LF100 & 300 mitigated the ethanol-induced gastric ulcer via modulation of both oxidative stress and inflammatory responses.

Achillea millefolium Essential Oil Mitigates Peptic Ulcer in Rats through Nrf2/HO-1 Pathway

Extreme ethanol ingestion is associated with developing gastric ulcers. Achillea millefolium (yarrow) is one of the most commonly used herbs with numerous proven pharmacological actions. The goal of the hereby investigation is to explore the gastroprotective action of yarrow essential oil against ethanol-induced gastric ulcers and to reveal the unexplored mechanisms. Rats were distributed into five groups (n = 6); the control group administered 10% Tween 20, orally, for two weeks; the ethanol group administered absolute ethanol (5 mL/kg) to prompt gastric ulcer on the last day of the experiment. Yarrow essential oil 100 or 200 mg/kg + ethanol groups pretreated with yarrow oil (100 or 200 mg/kg, respectively), orally, for two weeks prior to gastric ulcer induction by absolute ethanol. Lanso + ethanol group administered 20 mg/kg lansoprazole, orally, for two weeks prior to gastric ulcer induction by ethanol. Results of the current study showed that ethanol caused several macroscopic and microscopic alterations, amplified lipid peroxidation, pro-inflammatory cytokines, and apoptotic markers, as well as diminished PGE₂, NO, and antioxidant enzyme activities. On the other hand, animals pretreated with yarrow essential oil exhibited fewer macroscopic and microscopic modifications, reduced ulcer surface, and increased Alcian blue binding capacity, pH, and pepsin activity. In addition, yarrow essential oil groups exhibited reduced pro-inflammatory cytokines, apoptotic markers, and MDA, restored the PGE₂ and NO levels, and recovered the antioxidant enzyme activities. Ethanol escalated Nrf2 and HO-1 expressions, whereas pretreatment of yarrow essential oil caused further intensification in Nrf2 and HO-1. To conclude, the current study suggested yarrow essential oil as a gastroprotective agent against ethanol-induced gastric lesions. This gastroprotective effect could be related to the antioxidant, anti-inflammatory, and anti-apoptotic actions of the essential oil through the instigation of the Nrf2/HO-1 pathway.

Protective Effects of Piperine on Ethanol-Induced Gastric Mucosa Injury by Oxidative Stress Inhibition

Piper nigrum Linnaeus is often used as a treatment for chills, stomach diseases, and other ailments. Piperine has many biological functions; however, its mechanism for preventing gastric mucosal damage is still unclear. The objective of this study was to investigate the preventive effects of piperine on ethanol-induced gastric mucosal injury by using GES-1 cells and rats. SOD, CAT, GSH-Px and MDA were effectively regulated in GES-1 cells pre-treated with piperine. Piperine significantly increased SOD, CAT and GSH-Px activities, but decreased the ulcer area, MDA, ROS and MPO levels in the gastric tissues of rats. RT-PCR analysis showed that piperine downregulated the mRNA expression levels of keap1, JNK, ERK and p38, and upregulated the mRNA transcription levels of Nrf2 and HO-1. Western blotting results indicated that piperine could activate the protein expression levels of Nrf2 and HO-1 and inhibit the protein expression levels of keap1, p-JNK, p-ERK and p-p38. In conclusion, piperine suppressed ethanol-induced gastric ulcers in vitro and in vivo via oxidation inhibition and improving gastric-protecting activity by regulating the Nrf2/HO-1 and MAPK signalling pathways.

The lack of transcriptionally active Nrf2 triggers colon dysfunction in female mice - The role of estrogens

BACKGROUND AND AIM

The proper functioning of the gastrointestinal system relies on an intricate crosstalk between a plethora of cell types and signaling pathways. Recently we identified that the lack of NRF2 transcriptional activity (NRF2 tKO) triggers significant colon microscopical alterations, still they do not affect the general functioning of mice. Therefore, in this study, we aimed to address the gender-dependent impact of NRF2 transcriptional deficiency on colon function, and relate them to an established model of inflammatory bowel disease (IBD).

METHODS

In the study we subjected 3- and 6-month old mice deficient in IL-10 and NRF2 transcriptional activity and wild-type counterparts to tests assessing colon functionality, and histological analyses. To address the role of estrogens, we attempted to rescue the phenotype by the delivery of 17β-estradiol through subcutaneous implants.

RESULTS

In females, NRF2 transcriptional abrogation, like IL-10 deficiency, triggers a functional and microscopic phenotype, that resembles IBD. The females are significantly more affected by the dysfunctional phenotype, and the functional impairmentdecreases with age. We found that NRF2 transcriptional activity influences 17β-estradiol level and the estrogen receptors expression and location. Exogenous delivery of 17β-estradiol normalized colon motility in the NRF2 tKO mice, which is related to enhanced ERβ signaling.

CONCLUSIONS

Summing up, in this study, we underline that NRF2 transcriptional deficiency or the lack of IL-10 results in pronounced GI functional decline in young females. Mechanistically, we show that the impaired distal colon motility is dependent on ERβ signaling. Targeting estrogen signaling seems a promising therapeutic strategy to counteract colonic dysfunction.

Amelioration of ethanol-induced gastric ulcer in rats by quercetin: implication of Nrf2/HO1 and HMGB1/TLR4/NF-κB pathways

Gastric ulcer is a serious medical condition that can be developed due to an imbalance in the protective and destructive factors of the gastric system. Available therapies do not provide definite cure, thus, there is an urge to seek for alternative treatments. Quercetin is a natural flavonoid that possesses antioxidant and anti-inflammatory properties. In the current study, the antiulcerogenic effect of quercetin in ethanol-induced gastric ulcer (EI-GU) rat model was compared to Antodine® (a reference drug), to elucidate the potential underlying mechanisms. Quercetin (50 mg/kg) and Antodine® (20 mg/kg) were given orally for one week post ulcer induction by ethanol. EI-GU was associated with downregulation of SOD, CAT, Nrf2 and HO1, and accompanied by upregulation of inflammatory markers (i.e., HMGB1, NF-κB and TNFα) and an increase in Bax/Bcl2 ratio. Administration of quercetin resulted in a significant reduction in gastric volume in the stomach of ulcerative rats by 86% and a significant decrease in gastric lesion count by 3.5- folds, as compared with the ulcerative rats. Moreover, rats treated with quercetin showed upregulation of Nrf2 by 3.3-fold change and in HO1 by 3.5-fold change when compared to ulcerated rats, and decreased HMGB1, TLR4, NF-κB p65 and TNF-α by 50%, 53%, 52.9% and 54.9%, respectively. Treatment of rats with quercetin reduced Bax and Bax/Bcl2 ratio and increased Bcl2 relative to ulcerated rats. Thus, it can be concluded that the ulcerogenic curative properties of quercetin were mediated by antioxidant, anti-inflammatory and antiapoptotic activities.

Nrf2 Downregulation Contributes to Epithelial-to-Mesenchymal Transition in Helicobacter pylori-Infected Cells

Simple Summary

Gastric cancer is mainly linked to Helicobacter pylori infection. It is therefore important to decipher the mechanisms involved in H. pylori-induced gastric carcinogenesis, and especially the early events. We have previously demonstrated that the infection leads to an epithelial-to-mesenchymal transition (EMT) favoring gastric carcinogenesis. H. pylori infection is also associated with high levels of oxidative stress. In this work, we aimed at investigating the modulation of Nrf2, a major regulator of cellular antioxidant response to oxidative stress, upon infection with H. pylori and to decipher its implication in EMT. We demonstrated that H. pylori-induced Nrf2 downregulation may participate in gastric cells’ EMT, one crucial tumorigenic event in gastric cancer. These results could pave the way for new therapeutic strategies using Nrf2 modulators to reduce gastric carcinogenesis associated with H. pylori infection.

Abstract

Background: Gastric cancer, the fifth most common cancer worldwide, is mainly linked to Helicobacter pylori infection. H. pylori induces chronic inflammation of the gastric mucosa associated with high oxidative stress. Our study aimed at assessing the implication of Nrf2, a major regulator of cellular redox homeostasis, in H. pylori-induced gastric carcinogenesis. Methods: Using three different gastric epithelial cell lines, a non-cancerous (HFE-145) and two different subtypes of gastric cancer (AGS and MKN74), we analyzed the modulation of Nrf2 expression over time. After invalidation of Nrf2 by CRISPR-cas9, we assessed its role in H. pylori-induced epithelial-to-mesenchymal transition (EMT). Finally, we evaluated the expression of Nrf2 and ZEB1, a central EMT transcription factor, in human gastric tissues. Results: We first demonstrated that the Nrf2 signaling pathway is differentially regulated depending on the infection stage. Rapidly and transiently activated, Nrf2 was downregulated 24 h post-infection in a VacA-dependent manner. We then demonstrated that Nrf2 invalidation leads to increased EMT, which is even exacerbated after H. pylori infection. Finally, Nrf2 expression tended to decrease in human patients’ gastric mucosa infected with H. pylori. Conclusions: Our work supports the hypothesis that Nrf2 downregulation upon H. pylori infection participates in EMT, one of the most important events in gastric carcinogenesis.

Therapeutic Potential of Quercetin Loaded Nanoparticles: Novel Insights in Alleviating Colitis in an Experimental DSS Induced Colitis Model

Oxidative stress is considered the main etiologic factor involved in inflammatory bowel disease (IBD). Integration of nanocarriers for natural therapeutic agents with antioxidant and anti-inflammatory potential is a novel promising candidate for curing IBD. Herein, the colonic antioxidant and anti-inflammatory effects of different concentrations of quercetin nanoparticles (QT-NPs) were evaluated using a dextran sulfate sodium (DSS)-induced colitis model. Following colitis induction, the efficacy and mechanistic actions of QT-NPs were evaluated by assessing lesion severity, molecular aids controlling oxidative stress and inflammatory response, and histopathological and immunohistochemistry examination of colonic tissues. Administration of QT-NPs, especially at higher concentrations, significantly reduced the disease activity index and values of fecal calprotectin marker compared to the colitic group. Colonic oxidant/antioxidant status (ROS, H2O2, MDA, SOD, CAT, GPX and TAC) was restored after treatment with higher concentrations of QT-NPs. Moreover, QT-NPs at levels of 20 mg/kg and, to a lesser extent, 15 mg/kg reduced Nrf2 and HO-1 gene expression, which was in line with decreasing the expression of iNOS and COX2 in colonic tissues. Higher concentrations of QT-NPs greatly downregulated pro-inflammatory cytokines; upregulated genes encoding occludin, MUC-2 and JAM; and restored the healthy architectures of colonic tissues. Taken together, these data suggest that QT-NPs could be a promising alternative to current IBD treatments.

The ameliorative impacts of wheat germ oil against ethanol-induced gastric ulcers: involvement of anti-inflammatory, antiapoptotic, and antioxidant activities

This study examined if wheat germ oil (WGO) has gastroprotective impacts against ethanol-induced gastric ulcer in rats. Rats were assigned into control, WGO, ethanol, omeprazole + ethanol, and WGO + ethanol. WGO prevented gastric ulceration and damage induced by ethanol, the same effect induced by omeprazole, a widely known medication used for gastric ulcer treatment. WGO reduced gastric ulcer index, nitric oxide, and malondialdehyde levels in the stomach. WGO boosted the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), Bcl2, and the antioxidants. WGO showed inflammatory and anti-inflammatory impacts through the control of interleukin (IL)-1β, Tumor necrosis factor alpha (TNF-α), and IL-10 that were altered in ethanol-administered rats. Ethanol up-regulated caspase-3 and nuclear factor-kappa B (NF-kB) expression and showed histopathological changes such as necrosis and mucosal degeneration that were mitigated by pre-administration of WGO. Moreover, WGO decreased gastric immunoreactivity of NF-kB and increased transforming growth factor beta-1 (TGF-β1) that were associated with upregulation of Nrf2, heme oxygenase-1 (HO-1), and antioxidant expression and production. In conclusion, WGO reduced ethanol-induced stomach toxicity by regulating genes involved in oxidative stress, inflammation, and apoptotic/antiapoptotic pathways.

Recent Advances in Understanding Nrf2 Agonism and Its Potential Clinical Application to Metabolic and Inflammatory Diseases

Oxidative stress is a major component of cell damage and cell fat, and as such, it occupies a central position in the pathogenesis of metabolic disease. Nuclear factor-erythroid-derived 2-related factor 2 (Nrf2), a key transcription factor that coordinates expression of genes encoding antioxidant and detoxifying enzymes, is regulated primarily by Kelch-like ECH-associated protein 1 (Keap1). However, involvement of the Keap1–Nrf2 pathway in tissue and organism homeostasis goes far beyond protection from cellular stress. In this review, we focus on evidence for Nrf2 pathway dysfunction during development of several metabolic/inflammatory disorders, including diabetes and diabetic complications, obesity, inflammatory bowel disease, and autoimmune diseases. We also review the beneficial role of current molecular Nrf2 agonists and summarize their use in ongoing clinical trials. We conclude that Nrf2 is a promising target for regulation of numerous diseases associated with oxidative stress and inflammation. However, more studies are needed to explore the role of Nrf2 in the pathogenesis of metabolic/inflammatory diseases and to review safety implications before therapeutic use in clinical practice.

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.

Revisiting the Oxidation of Flavonoids: Loss, Conservation or Enhancement of Their Antioxidant Properties

Flavonoids display a broad range of health-promoting bioactivities. Among these, their capacity to act as antioxidants has remained most prominent. The canonical reactive oxygen species (ROS)-scavenging mode of the antioxidant action of flavonoids relies on the high susceptibility of their phenolic moieties to undergo oxidation. As a consequence, upon reaction with ROS, the antioxidant capacity of flavonoids is severely compromised. Other phenol-compromising reactions, such as those involved in the biotransformation of flavonoids, can also markedly affect their antioxidant properties. In recent years, however, increasing evidence has indicated that, at least for some flavonoids, the oxidation of such residues can in fact markedly enhance their original antioxidant properties. In such apparent paradoxical cases, the antioxidant activity arises from the pro-oxidant and/or electrophilic character of some of their oxidation-derived metabolites and is exerted by activating the Nrf2–Keap1 pathway, which upregulates the cell’s endogenous antioxidant capacity, and/or, by preventing the activation of the pro-oxidant and pro-inflammatory NF-κB pathway. This review focuses on the effects that the oxidative and/or non-oxidative modification of the phenolic groups of flavonoids may have on the ability of the resulting metabolites to promote direct and/or indirect antioxidant actions. Considering the case of a metabolite resulting from the oxidation of quercetin, we offer a comprehensive description of the evidence that increasingly supports the concept that, in the case of certain flavonoids, the oxidation of phenolics emerges as a mechanism that markedly amplifies their original antioxidant properties. An overlooked topic of great phytomedicine potential is thus unraveled.

Investigating the Potential for Sulforaphane to Attenuate Gastrointestinal Dysfunction in mdx Dystrophic Mice

Gastrointestinal (GI) dysfunction is an important, yet understudied condition associated with Duchenne muscular dystrophy (DMD), with patients reporting bloating, diarrhea, and general discomfort, contributing to a reduced quality of life. In the mdx mouse, the most commonly used mouse model of DMD, studies have confirmed GI dysfunction (reported as altered contractility and GI transit through the small and large intestine), associated with increased local and systemic inflammation. Sulforaphane (SFN) is a natural isothiocyanate with anti-inflammatory and anti-oxidative properties via its activation of Nrf2 signalling that has been shown to improve aspects of the skeletal muscle pathology in dystrophic mice. Whether SFN can similarly improve GI function in muscular dystrophy was unknown. Video imaging and spatiotemporal mapping to assess gastrointestinal contractions in isolated colon preparations from mdx and C57BL/10 mice revealed that SFN reduced contraction frequency when administered ex vivo, demonstrating its therapeutic potential to improve GI function in DMD. To confirm this in vivo, four-week-old male C57BL/10 and mdx mice received vehicle (2% DMSO/corn oil) or SFN (2 mg/kg in 2% DMSO/corn oil) via daily oral gavage five days/week for 4 weeks. SFN administration reduced fibrosis in the diaphragm of mdx mice but did not affect other pathological markers. Gene and protein analysis revealed no change in Nrf2 protein expression or activation of Nrf2 signalling after SFN administration and oral SFN supplementation did not improve GI function in mdx mice. Although ex vivo studies demonstrate SFN’s therapeutic potential for reducing colon contractions, in vivo studies should investigate higher doses and/or alternate routes of administration to confirm SFN’s potential to improve GI function in DMD.

Chemical characterization of Tianshan green tea polysaccharides and its protective effects on cell oxidative injury

The purpose of this study was to analyze the chemical characterization of Tianshan green tea polysaccharides (TSPS), and evaluate its antioxidant activity by chemical-based and cellular-based antioxidant models in vitro. The results showed that the TSPS were composed of mannose, ribose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, arabinose, and fucose with a molar ratio of 14.5:33.5:10.5:6.5:111.5:22.3:59.5:51: 1.0, and an average molecular weight of 19.49 kDa. TSPS exhibited excellent antioxidant ability to DPPH radical, hydroxyl radical, and ABTS radical, and enhanced the ferric-reducing power (FRAP). The antioxidation model of LO2 and HepG2 cells was established, and found that TSPS had no significant toxicity to either of the two cells at the range of 0.1-5 mg/mL, but clearly protected cells from H₂ O₂ -induced apoptosis and significantly reduced intracellular ROS level. In addition, the activities of antioxidant-associated enzymes were detected in LO2 cells, which suggested that TSPS could significantly improve the activities of SOD and CAT enzyme when the concentration was higher than 0.5 mg/mL. Furthermore, TSPS activated the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway by promoting Nrf2 nuclear translocation and inhibited the expression of Kelch-like ECH-associated protein 1 (Keap-1) and enhanced the expression of heme oxygenase-1 (HO-1). PRACTICAL APPLICATIONS: Tianshan green tea, a local variety in Fujian Province, belongs to unfermented tea. Polysaccharide is considered as the most promising component in Tianshan green tea. This study showed that TSPS had excellent antioxidant activity and had no significant toxicity to cells, which provides a scientific foundation and new idea for its further development and application in functional foods.

Commiphora myrrh Supplementation Protects and Cures Ethanol-Induced Oxidative Alterations of Gastric Ulceration in Rats

Gastric ulceration is a multifactorial disease defined as a defect in the gastric wall that extends through the muscularis mucosae into the deeper layers of the wall. The most common cause of gastric ulceration is alcohol consumption. In the current study, rats were gavaged by ethanol to investigate the protective (before ethanol) and curative (after ethanol) ability of Commiphora myrrh (myrrh) oil and extract against gastric ulcer oxidative alterations induced by ethanol. Myrrh significantly improved ulcer index, histomorphology, and periodic acid Schiff (PAS) impaired by ethanol. In addition, myrrh improved the antioxidant potential of gastric mucosa through enhancement of nuclear factor related to erythroid 2 (Nrf2), total glutathione (GSH), reduced GSH, and oxidized glutathione (GSSG), along with significant reduction in malondialdehyde (MDA) levels. Amelioration of gastric oxidative stress by myrrh enables gastric mucosa to counteract the ethanol’s inflammatory and apoptotic processes leading to improved gastric proliferation and healing. Interestingly, myrrh extract showed better protective and curative effects than myrrh oil against gastric ulceration.

Olmesartan niosomes ameliorates the Indomethacin-induced gastric ulcer in rats: Insights on MAPK and Nrf2/HO-1 signaling pathway

AIMS

Gastric ulcer is a continuous worldwide threat that inquires protective agents. Olmesartan (OLM) has potent anti-oxidant and anti-inflammatory characters, yet having limited bioavailability. We targeted the gastro-protective potential and probable mechanism of OLM and its niosomal form against indomethacin (IND) induced-gastric ulcer in rats.

MAIN METHODS

we prepared OLM niosomes (OLM-NIO) with different surfactant: cholesterol molar ratios. We evaluated particle size, zeta-potential, polydispersity, and entrapment efficiency. In-vitro release study, Fourier transform infrared spectroscopy, differential scanning calorimetry, and transmission electron microscopy were performed for selected niosomes. In-vivo, we used oral Omeprazole (30 mg/kg), OLM or OLM-NIO (10 mg/kg) for 3 days before IND (25 mg/kg) ingestion. We assessed gastric lesions, oxidative and inflammatory markers.

KEY FINDINGS

OLM-NIO prepared with span 60:cholesterol ratio (1:1) showed high entrapment efficiency 93 ± 2%, small particle size 159.3 ± 6.8 nm, low polydispersity 0.229 ± 0.009, and high zeta-potential -35.3 ± 1.2 mV, with sustained release mechanism by release data. In-vivo macroscopical and histological results showed gastro-protective effects of OLM pretreatment, which improved oxidative stress parameters and enhanced the gastric mucosal cyclooxygenase-1 (COX-1) and prostaglandin E2 (PGE2) contents. OLM pretreatment suppressed interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) contents and translocation of p38 mitogen-activated protein kinase (p38-MAPK). Besides, OLM substantially promoted the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) protective pathway. OLM-NIO furtherly improved all previous outcomes.

SIGNIFICANCE

We explored OLM anti-ulcerative effects, implicating oxidative stress and inflammation improvement, mediated by the Nrf2/HO-1 signaling pathway and p38-MAPK translocation. Meanwhile, the more bioavailable OLM-NIO achieved better gastro-protective effects compared to conventional OLM form.

The role of Nrf2 pathway in alleviating fluorine-induced apoptosis by different selenium sources in the chicken duodenum and jejunum

In order to evaluate the alleviative effects and molecular mechanisms of sodium selenite (SS) and selenomethionine (SM) on excessive apoptosis induced by high fluorine (HF) in the duodenum and jejunum of broilers, 720 1 day old Lingnan Yellow broilers were randomly divided into 4 groups (each group assigned 180 chickens with 6 replicates) and offered either a control diet or test diets (800 mg/kg F, HF group; 800 mg/kg F + 0.15 mg selenium (Se)/kg as SS (SS group) or SM (SM group)) for 50 days. High F intake significantly increased (P < 0.05) apoptosis rates of duodenum and jejunum by inducing oxidative stress and leading to mitochondrial damage. Selenomethionine supplementation effectively alleviated mitochondrial damage and severe apoptosis of duodenum and jejunum caused by HF through decreasing oxidative stress parameters. Selenomethionine added group significantly increased (P < 0.05) nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA and nuclear Nrf2 protein levels as well as Nrf2 downstream antioxidant enzymes expressions in the duodenum and jejunum when compared with the HF group. Selenomethionine was superior to SS in activating the Nrf2 pathway and reducing the apoptosis rate of duodenum. It was concluded that dietary SM supplementation could ameliorate F-induced excessive apoptosis by inducing the Nrf2 pathway. Our findings will bring a promising tactics for the utilization of SM as an efficient antioxidant additive for reducing the intestinal damage caused by fluorosis in poultry.

Benzyl isothiocyanates modulate inflammation, oxidative stress, and apoptosis via Nrf2/HO-1 and NF-κB signaling pathways on indomethacin-induced gastric injury in rats

The present study investigated the gastroprotective activity of benzyl isothiocyanates (BITC) on indomethacin (IND)-induced gastric injury in a rat model and explicated the possible involved biochemical, cellular, and molecular mechanisms. The rat model with gastric ulcers was established by a single oral dose of IND (30 mg per kg b.wt). BITC (0.75 and 1.5 mg kg^-1) and esomeprazole (20 mg per kg b.wt) were orally administered for 3 weeks to rats before the induction of gastric injury. Compared with the IND group, BITC could diminish both the macroscopic and microscopic pathological morphology of gastric mucosa. BITC significantly preserved the antioxidants (glutathione GSH, superoxide dismutase SOD), nitric oxide (NO), and prostaglandin E2 (PGE2) contents, while decreasing the gastric mucosal malondialdehyde (MDA), tumor necrosis factor alpha (TNFα), and myeloperoxidase (MPO) contents. Moreover, BITC remarkably upregulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), hemoxygenase-1 (HO-1), and NAD(P)H : quinone oxidoreductase (NQO1). In addition, BITC activates the expression of heat shock protein 70 (HSP-70) and downregulated the expression of nuclear factor-κB (NF-κB) and caspase-3 to promote gastric mucosal cell survival. To the best of our knowledge, this study is the first published report to implicate the suppression of inflammation, oxidative stress, and Nrf2 signaling pathway as a potential mechanism for the gastroprotective activity of BITC.

The intervention of tert-butylhydroquinone protects ethanol-induced gastric ulcer in type II diabetic rats: the role of Nrf2 pathway

Ethanol consumption increases the prevalence of gastric ulcer (GU) in rats with type II diabetes (T2D). Induction of GU by absolute ethanol (5 mL/kg or 3.94 g/kg) in the animal model resembles human ulcer characteristics. The aim was to investigate the role of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in the treatment of GU in diabetic condition. The rats were exposed to absolute ethanol 1 h before sacrifice and T2D was induced by combined exposure of high-fat diet and low dose streptozotocin. Pretreatment of tert-butylhydroquinone (tBHQ) (25 and 50 mg/kg), metformin (500 mg/kg), and omeprazole (20 mg/kg) were given once daily for last three consecutive weeks. In ethanol-exposed diabetic rats, pretreatment with tBHQ, omeprazole, and metformin reduced gastric mucosal lesion, ulcer index, histological alterations, malondialdehyde level, and apoptosis. Furthermore, the intervention of tBHQ, omeprazole, and metformin improved the integrity of the stomach mucosa, glutathione, gastric pH, collagen, and goblet cells. tBHQ treatment improved ethanol-induced alterations of Nrf2, catalase, heat shock protein 70 (HSP70), NF-κB, and endothelin-1 expressions in diabetic rats. In diabetic conditions, the incidence of GU is increased due to elevated levels of reactive oxygen species, inflammatory mediators, depleted levels of cellular antioxidants, and altered gastric parameters. The tBHQ intervention could be a rational strategy to protect these changes.

Gastroprotective Effect of Sinapic Acid on Ethanol-Induced Gastric Ulcers in Rats: Involvement of Nrf2/HO-1 and NF-κB Signaling and Antiapoptotic Role

Background: In the current study, we evaluated the therapeutic potential of sinapic acid (SA) in terms of the mechanism underlying its gastroprotective action against ethanol-induced gastric ulcers in rats.

Methods: These effects were examined through gross macroscopic evaluation of the stomach cavity [gastric ulcer index (GUI)], alteration in pH, gastric juice volume, free acidity, total acidity, total gastric wall mucus, and changes in PGE2. In addition, we evaluated lipid peroxidation (malondialdehyde), antioxidant systems (catalase and glutathione), inflammatory markers [tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and myeloperoxidase (MPO)], apoptotic markers (caspase-3, Bax, and Bcl-2), nuclear factor-κB [NF-κB (p65)], NO levels, and histopathological staining (H and E and PAS).

Results: In rats with ethanol-induced ulcers, pre-treatment with SA (40 mg/kg p. o.) decreased the sternness of ethanol-induced gastric mucosal injuries by decreasing the GUI, gastric juice volume, free acidity, and total acidity. In addition, the pH and total gastric mucosa were increased, together with histopathological alteration, neutrophil incursion, and increases in PGE2 and NO₂. These effects were similar to those observed for omeprazole, a standard anti-ulcer drug. SA was shown to suppress gastric inflammation through decreasing TNF-α, IL-6, and MPO, as well as curbing gastric oxidative stress through the inhibition of lipid peroxidation (MDA) and restoration of depleted glutathione and catalase activity. SA inhibited Bcl-2-associated X (Bax) and caspase-3 activity, and restored the antiapoptotic protein Bcl-2; these findings indicate the antiapoptotic potential of SA, leading to enhanced cell survival. SA also repressed NF-κB signaling and increased IκBα. Moreover, SA upregulated the nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), thereby restoring depleted antioxidant defense enzymes and implicating the NRF2/HO-1 signaling pathways.

Conclusion: These results suggest that the prophylactic administration of SA (40 mg/kg) can ameliorate ethanol-induced gastric ulcers in rats primarily via the modulation of Nrf2/HO-1 and NF-κB signaling and subsequent enhancement of cell viability.

New insights into the role of the Nrf2 signaling pathway in green tea catechin applications

Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a transcriptional signaling pathway that plays a crucial role in numerous clinical complications. Pivotal roles of Nrf2 have been proved in cancer, autoimmune diseases, neurodegeneration, cardiovascular diseases, diabetes mellitus, renal injuries, respiratory conditions, gastrointestinal disturbances, and general disorders related to oxidative stress, inflammation, apoptosis, gelatinolysis, autophagy, and fibrogenesis processes. Green tea catechins as a rich source of phenolic compounds can deal with various clinical problems and manifestations. In this review, we attempted to focus on intervention between green tea catechins and Nrf2. Green tea catechins especially epigallocatechin gallate (EGCG) elucidated the protective role of Nrf2 and its downstream molecules in various disorders through Keap-1, HO-1, NQO-1, GPx, GCLc, GCLm, NF-kB cross-link, kinases, and apoptotic proteins. Subsequently, we compiled an updated expansions of the Nrf2 role as a gate to manage and protect different disorders and feasible indications of green tea catechins through this signaling pathway. The present review highlighted recent evidence-based data in silico, in vitro, and in vivo studies on an outline for future clinical trials.

Potential of Sulforaphane as a Natural Immune System Enhancer: A Review

Brassicaceae are an outstanding source of bioactive compounds such as ascorbic acid, polyphenols, essential minerals, isothiocyanates and their precursors, glucosinolates (GSL). Recently, GSL gained great attention because of the health promoting properties of their hydrolysis products: isothiocyanates. Among them, sulforaphane (SFN) became the most attractive one owing to its remarkable health-promoting properties. SFN may prevent different types of cancer and has the ability to improve hypertensive states, to prevent type 2 diabetes–induced cardiomyopathy, and to protect against gastric ulcer. SFN may also help in schizophrenia treatment, and recently it was proposed that SFN has potential to help those who struggle with obesity. The mechanism underlying the health-promoting effect of SFN relates to its indirect action at cellular level by inducing antioxidant and Phase II detoxifying enzymes through the activation of transcription nuclear factor (erythroid-derived 2)-like (Nrf2). The effect of SFN on immune response is generating scientific interest, because of its bioavailability, which is much higher than other phytochemicals, and its capacity to induce Nrf2 target genes. Clinical trials suggest that sulforaphane produces favorable results in cases where pharmaceutical products fail. This article provides a revision about the relationship between sulforaphane and immune response in different diseases. Special attention is given to clinical trials related with immune system disorders.

Formulation, optimization and characterization of allantoin-loaded chitosan nanoparticles to alleviate ethanol-induced gastric ulcer: in-vitro and in-vivo studies

Allantoin (ALL) is a phytochemical possessing an impressive array of biological activities. Nonetheless, developing a nanostructured delivery system targeted to augment the gastric antiulcerogenic activity of ALL has not been so far investigated. Consequently, in this survey, ALL-loaded chitosan/sodium tripolyphosphate nanoparticles (ALL-loaded CS/STPP NPs) were prepared by ionotropic gelation technique and thoroughly characterized. A full 24 factorial design was adopted using four independently controlled parameters (ICPs). Comprehensive characterization, in vitro evaluations as well as antiulcerogenic activity study against ethanol-induced gastric ulcer in rats of the optimized NPs formula were conducted. The optimized NPs formula, (CS (1.5% w/v), STPP (0.3% w/v), CS:STPP volume ratio (5:1), ALL amount (13 mg)), was the most convenient one with drug content of 6.26 mg, drug entrapment efficiency % of 48.12%, particle size of 508.3 nm, polydispersity index 0.29 and ζ-potential of + 35.70 mV. It displayed a sustained in vitro release profile and mucoadhesive strength of 45.55%. ALL-loaded CS/STPP NPs (F-9) provoked remarkable antiulcerogenic activity against ethanol-induced gastric ulceration in rats, which was accentuated by histopathological, immunohistochemical (IHC) and biochemical studies. In conclusion, the prepared ALL-loaded CS/STPP NPs could be presented to the phytomedicine field as an auspicious oral delivery system for gastric ulceration management.

Natural Xanthones and Skin Inflammatory Diseases: Multitargeting Mechanisms of Action and Potential Application

The pathogenesis of skin inflammatory diseases such as atopic dermatitis, acne, psoriasis, and skin cancers generally involve the generation of oxidative stress and chronic inflammation. Exposure of the skin to external aggressors such as ultraviolet (UV) radiation and xenobiotics induces the generation of reactive oxygen species (ROS) which subsequently activates immune responses and causes immunological aberrations. Hence, antioxidant and anti-inflammatory agents were considered to be potential compounds to treat skin inflammatory diseases. A prime example of such compounds is xanthone (xanthene-9-one), a class of natural compounds that possess a wide range of biological activities including antioxidant, anti-inflammatory, antimicrobial, cytotoxic, and chemotherapeutic effects. Many studies reported various mechanisms of action by xanthones for the treatment of skin inflammatory diseases. These mechanisms of action commonly involve the modulation of various pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor α (TNF-α), as well as anti-inflammatory cytokines such as IL-10. Other mechanisms of action include the regulation of NF-κB and MAPK signaling pathways, besides immune cell recruitment via modulation of chemokines, activation, and infiltration. Moreover, disease-specific activity contributed by xanthones, such as antibacterial action against Propionibacterium acnes and Staphylococcus epidermidis for acne treatment, and numerous cytotoxic mechanisms involving pro-apoptotic and anti-metastatic effects for skin cancer treatment have been extensively elucidated. Furthermore, xanthones have been reported to modulate pathways responsible for mediating oxidative stress and inflammation such as PPAR, nuclear factor erythroid 2-related factor and prostaglandin cascades. These pathways were also implicated in skin inflammatory diseases. Xanthones including the prenylated α-mangostin (2) and γ-mangostin (3), glucosylated mangiferin (4) and the caged xanthone gambogic acid (8) are potential lead compounds to be further developed into pharmaceutical agents for the treatment of skin inflammatory diseases. Future studies on the structure-activity relationships, molecular mechanisms, and applications of xanthones for the treatment of skin inflammatory diseases are thus highly recommended.

A Review of the Role of Flavonoids in Peptic Ulcer (2010-2020)

Peptic ulcers are characterized by erosions on the mucosa of the gastrointestinal tract that may reach the muscle layer. Their etiology is multifactorial and occurs when the balance between offensive and protective factors of the mucosa is disturbed. Peptic ulcers represent a global health problem, affecting millions of people worldwide and showing high rates of recurrence. Helicobacter pylori infection and the use of non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most important predisposing factors for the development of peptic ulcers. Therefore, new approaches to complementary treatments are needed to prevent the development of ulcers and their recurrence. Natural products such as medicinal plants and their isolated compounds have been widely used in experimental models of peptic ulcers. Flavonoids are among the molecules of greatest interest in biological assays due to their anti-inflammatory and antioxidant properties. The present study is a literature review of flavonoids that have been reported to show peptic ulcer activity in experimental models. Studies published from January 2010 to January 2020 were selected from reference databases. This review refers to a collection of flavonoids with antiulcer activity in vivo and in vitro models.

NADPH oxidase 4 is protective and not fibrogenic in intestinal inflammation

Dysregulated redox signaling and oxidative injury are associated with inflammatory processes and fibrosis. H₂O₂ generation by NOX4 has been suggested as a key driver in the development of fibrosis and a small molecule drug is under evaluation in clinical trials for idiopathic pulmonary fibrosis and primary biliary cholangitis. Fibrosis is a common complication in Crohn's disease (CD) leading to stricture formation in 35-40% of patients, who require surgical interventions in the absence of therapeutic options. Here we assess NOX4 expression in CD patients with inflammatory or stricturing disease and examine whether loss of NOX4 is beneficial in acute and fibrotic intestinal disease. NOX4 was upregulated in inflamed mucosal tissue of CD and ulcerative colitis (UC) patients, in CD ileal strictures, and in mice with intestinal inflammation. Nox4 deficiency in mice promoted pathogen colonization and exacerbated tissue injury in acute bacterial and chemical colitis. In contrast, in two chronic injury models aberrant tissue remodeling and fibrosis-related gene expression did not differ substantially between Nox4^-/- mice and wildtype mice, suggesting that Nox4 is dispensable in TGF-β1-driven intestinal fibrogenesis. While animal models do not recapitulate all the hallmarks of CD fibrosis, the tissue-protective role of Nox4 warrants a cautious approach to pharmacological inhibitors.

The Synthetic Myeloperoxidase Inhibitor AZD3241 Ameliorates Dextran Sodium Sulfate Stimulated Experimental Colitis

Chronic inflammatory bowel disease (IBD) is a condition with multifactorial pathophysiology. To date, there is no permanent cure and the disease is primarily managed by immunosuppressive drugs; long-term use promotes serious side effects including increased risk malignancies. The current study aimed to target neutrophil-myeloperoxidase, a key contributor to the pathogenesis of IBD, through the use of AZD3241that inhibits extracellular myeloperoxidase. Experimental colitis was induced in C57BL/6 male mice by 2% dextran sodium sulfate in drinking water ad libitum over 9 days. Mice received either normal drinking water and peanut butter (control), 2% DSS in drinking water and peanut butter or 2% DSS in drinking water and AZD3241 (30 mg/kg) dispersed in peanut butter daily for 9 days. Administered AZD3241 attenuated body weight loss (10% p<0.05) and improved clinical score (9 fold p<0.05; a score comprising the time-dependent assessment of stool consistency and extent of rectal bleeding), loss of colonic crypts (p<0.001), preserved surface epithelium (p<0.001) and enhanced expression of the transcription factor Nrf-2 (regulator of antioxidants) and enhanced expression of the downstream antioxidant response element haeoxygenase-1 (HO-1) in the colon tissue. Also, the concentration of fecal hemoglobin and the myeloperoxidase specific oxidative damage biomarker 3-chlorotyrosine in the colon were significantly decreased in the presence of AZD3241. This latter result was consistent with AZD3241 inhibiting MPO activity in vitro. Overall, AZD3241 ameliorated the course and severity of experimental colitis through ameliorating MPO derived tissue damage and could be considered a potential therapeutic option, subject to further validation in chronic IBD models.

Dietary polyacetylene falcarinol upregulated intestinal heme oxygenase-1 and modified plasma cytokine profile in late phase lipopolysaccharide-induced acute inflammation in CB57BL/6 mice

Unlike polyphenols, which are widely available in the diet, polyacetylenes are available only from the Apiaceae family vegetables, including carrot, parsnip, fennel, celery, and many herbs (parsley, lovage, etc). The aim of this study was to investigate the hypothesis that polyacetylene falcarinol (FA) reduces intestinal inflammation and examine its similarity of effect to isothiocyanate R-sulforaphane during the late phase of acute inflammation. To this end, 3-month-old male CB57BL/6 mice were fed twice daily for 1 week with 5 mg/kg of FA, sulforaphane, or vehicle before receiving an intraperitoneal injection of 5 mg/kg endotoxin (lipopolysaccharide [LPS]) to induce modest acute inflammation. The expression of intestinal and hepatic heme oxygenase-1 at the mRNA and protein levels, circulating cytokines, as well as intestinal and mesenteric n-6 and n-3 fatty acid lipid mediators was compared 24 hours after LPS administration to examine its effects on the late phase of inflammation. Intestinal nuclear factor (erythroid-derived 2)-like 2 target enzyme heme oxygenase-1 was upregulated 8.42-fold at the mRNA level and 10.7-fold at the protein level by FA-supplemented diet. However, the FA-supplemented diet produced a unique type-2 plasma cytokine skew after LPS treatment. Plasma cytokines interleukin (IL)-4, IL-13, IL-9, and IL-10 were upregulated, reflecting the cytokine profile of reduced type 1 inflammation. A detailed lipidomic analysis of n-6 and n-3 fatty acid pro- and anti-inflammatory pathways in the mesentery and intestinal mucosa showed that FA diet was more similar to the control groups than to other LPS treated groups. In this study, we demonstrated that FA-supplemented diet produced a unique immunomodulatory effect not observed with sulforaphane in late phases of inflammation. These results support the hypothesis that FA may have role as a dietary immunosuppressant in patients with inflammatory gastrointestinal as well as other inflammatory disorders that may be alleviated by increasing consumption of carrot or other FA-containing food sources.

Protective effects of bovine milk exosomes against oxidative stress in IEC-6 cells

PURPOSE

Bovine milk exosomes, which are enriched with microRNAs (miRNAs) and proteins, regulate immune response and growth. In the present study, we aimed to assess the protective effects of bovine milk exosomes against oxidative stress of intestinal crypt epithelial cells (IEC-6).

METHODS

Bovine milk exosomes were isolated and characterized. To assess the protective effects of exosomes, IEC-6 cells were pretreated with exosomes, followed by H₂O₂. Cell viability and levels of superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase (GPX), reactive oxidative species (ROS), and lactate dehydrogenase (LDH) were measured. The expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (Ho1) genes, and miR-146a, miR-155, and the HO-1 protein were also determined.

RESULTS

The isolated bovine milk exosome were positive for CD63 and CD9 expression. The exosomes were approximately circular and had a diameter of about 67.23 nm. Pretreatment of IEC-6 cells with bovine milk exosomes enhanced cell viability; increased SOD and GPX activities; and reduced LDH, ROS, and MDA levels after H₂O₂ challenge. Further analysis showed that exosome pretreatment increased intracellular miR-146a and miR-155 levels. Exosome pretreatment inhibited the elevation of Nrf2 and Ho1 gene expression induced by H₂O₂, but promoted HO-1 protein expression.

CONCLUSION

The results indicated that bovine milk exosomes exerted protective effects against oxidative stress in IEC-6 cells.

Ethanol-induced gastric ulcer in rats and intervention of tert-butylhydroquinone: Involvement of Nrf2/HO-1 signalling pathway

Gastric ulcer (GU) is the most common health concern that occurs due to alcohol consumption, smoking and physiological stress. Ethanol-induced GU in animal model resembles the pathophysiology of human ulcer. The present study was designed to investigate the cytoprotective and anti-inflammatory properties of tert-butylhydroquinone (tBHQ), a nuclear factor erythroid 2-related factor 2 (Nrf2) activator, against gastric mucosal damage induced by acute exposure of ethanol (5 ml/kg). The intervention of tBHQ (25 and 50 mg/kg, per os (po)) and omeprazole (20 mg/kg, po) was done for 10 consecutive days. Omeprazole was chosen as a standard drug because it is prescribed for the treatment of GU. Pretreatment of tBHQ decreased gastric mucosal lesion, ulcer index, apoptotic cells and lipid peroxidation level induced by ethanol. Furthermore, the intervention of tBHQ increased gastric mucosa integrity, pH, reduced glutathione, collagen and mucus-producing goblet cells. Intervention of tBHQ increased the expression of antioxidant markers such as Nrf2, haeme oxygenase-1 and catalase and decreased the expressions of inflammatory markers such as nuclear factor kappa-light-chain-enhancer of activated B cells and cyclooxygenase-2. The cytoprotective potential of tBHQ against gastric mucosal damage might be due to its ability to enhance cellular antioxidants and anti-inflammatory responses.

Sulforaphane Protects Cells against Lipopolysaccharide-Stimulated Inflammation in Murine Macrophages

Inflammation is an essential part for the general or innate immune defenses to defend against tissue damage and accelerate the curing process by providing protection against pathogens. Sulforaphane (SFN) is a natural isothiocyanate that has potential properties against inflammation, along with other protective functions. The purpose of this study was to examine the mechanism of its protective effect on lipopolysaccharide (LPS)-induced inflammation in Raw 264.7 macrophages. Here, we compared LPS-challenged macrophages with or without SFN pretreatment. Macrophages were pre-incubated for 6 h with a wide range of concentrations of SFN (0 to 50 µM), and then treated with LPS for 24 h. Nitric oxide (NO) concentration and gene expression of different inflammatory mediators, i.e., interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-1β, were measured. SFN neither directly reacted with cytokines, nor with NO. To understand the mechanisms, we performed analyses of the expression of regulatory enzyme inducible nitic oxide synthase (iNOS), the transcription factor NF-E2-related factor 2 (Nrf2), and its enzyme heme-oxygenase (HO)-1. Our results revealed that LPS increased significantly the expression of inflammatory cytokines and concentration of NO in non-treated cells. SFN was able to prevent the expression of NO and cytokines through regulating inflammatory enzyme iNOS and activation of Nrf2/HO-1 signal transduction pathway.

Chronic toxicity of methamphetamine: Oxidative remodeling of pulmonary arteries

Methamphetamine (MA) has a high uptake in lung, but the precise mechanism of MA-induced lung toxicity remains unclear. The aim of this study is to investigate the role of MA abuse in remodeling of pulmonary arteries and to explore the possible correlation of the association of the remodeling with the redox imbalance in pulmonary arterial smooth muscle cells (PASMCs). Wistar rats were randomly divided into control group and MA group for the experimental study. We employed H&E staining, western blot, immunofluorescence, knockdown, flow in our experimental approach. Our studies shows that chronic exposure to MA led to weight loss, increased pulmonary arterial pressure, hypertrophy of right ventricle and remodeling of pulmonary arterial wall of rats. Our cell culture study with PASMCs indicates that MA significantly induced the imbalance between proliferation and apoptosis by upregulating the level of PCNA, Bcl-2 and reduction in the expression of BAX and Caspase 3. MA markedly prevented the nuclear translocation of Nrf2 to inhibit antioxidation. The knockdown of Nrf2 expression using siRNA significantly elevated the expression of SOD2/GCS and the production of ROS in PASMCs and even scaled up the amount of PASMCs induced by MA. Linear regression analysis showed that knockdown of Nrf2 promoted the positive correlation of relative ROS level with proliferation of PASMCs. Therefore, chronic exposure to MA induces pulmonary arterial remodeling by Nrf2-mediated imbalance of redox system to aggravate oxidative stress, and Nrf2 is a possible target for the treatment of MA-lung toxicity.

Sulforaphane: Its "Coming of Age" as a Clinically Relevant Nutraceutical in the Prevention and Treatment of Chronic Disease

A growing awareness of the mechanisms by which phytochemicals can influence upstream endogenous cellular defence processes has led to intensified research into their potential relevance in the prevention and treatment of disease. Pharmaceutical medicine has historically looked to plants as sources of the starting materials for drug development; however, the focus of nutraceutical medicine is to retain the plant bioactive in as close to its native state as possible. As a consequence, the potency of a nutraceutical concentrate or an extract may be lower than required for significant gene expression. The molecular structure of bioactive phytochemicals to a large extent determines the molecule's bioavailability. Polyphenols are abundant in dietary phytochemicals, and extensive in vitro research has established many of the signalling mechanisms involved in favourably modulating human biochemical pathways. Such pathways are associated with core processes such as redox modulation and immune modulation for infection control and for downregulating the synthesis of inflammatory cytokines. Although the relationship between oxidative stress and chronic disease continues to be affirmed, direct-acting antioxidants such as vitamins A, C, and E, beta-carotene, and others have not yielded the expected preventive or therapeutic responses, even though several large meta-analyses have sought to evaluate the potential benefit of such supplements. Because polyphenols exhibit poor bioavailability, few of their impressive in vitro findings have been replicated in vivo. SFN, an aliphatic isothiocyanate, emerges as a phytochemical with comparatively high bioavailability. A number of clinical trials have demonstrated its ability to produce favourable outcomes in conditions for which there are few satisfactory pharmaceutical solutions, foreshadowing the potential for SFN as a clinically relevant nutraceutical. Although myrosinase-inert broccoli sprout extracts are widely available, there now exist myrosinase-active broccoli sprout supplements that yield sufficient SFN to match the doses used in clinical trials.