Rheumatoid arthritis-recent advances in pathogenesis and the anti-inflammatory effect of plant-derived COX inhibitors

The majority of people with autoimmune disorders, including those with rheumatoid arthritis, osteoarthritis, and tendonitis report pain, stiffness, and inflammation as major contributors to their worse quality of life in terms of overall health. Of all the available treatment options, COX inhibitors are the ones that are utilized most frequently to ease the symptoms. Various signaling cascades have been reported to be involved in the pathogenesis of rheumatoid arthritis which includes JAK/STAT, MAPK, and NF-kB signaling pathways, and several allopathic inhibitors (tofacitinib and baricitinib) have been reported to target the components of these cascades and have received approval for RA treatment. However, the prolonged use of these COX inhibitors and other allopathic drugs can pose serious health challenges due to their significant side effects. Therefore, searching for a more effective and side effect-free treatment for rheumatoid arthritis has unveiled phytochemicals as both productive and promising. Their therapeutic ability helps develop potent and safe drugs targeting immune-inflammatory diseases including RA. Various scientific databases were used for searching articles such as NCBI, SpringerLink, BioMed Central, ResearchGate, Google Scholar, Scopus, Nature, Wiley Online Library, and ScienceDirect. This review lists various phytochemicals and discusses their potential molecular targets in RA treatment, as demonstrated by various in vitro, in vivo (pre-clinical), and clinical studies. Several pre-clinical and clinical studies suggest that various phytochemicals can be an alternative promising intervention for attenuating and managing inflammation-associated pathogenesis of rheumatoid arthritis.

Antiarthritic activity of Physalis peruviana fruit extract via inhibition of inflammatory mediators: Integrated in vitro, in vivo and in silico study

ETHNOPHARMACOLOGICAL RELEVANCE

P. peruviana fruit, native to Andean region, is cultivated worldwide for its adaptability to various soil natures and climatic conditions. It is increasingly consumed for its high nutritional profile and history of ethnomedical uses including treatment of arthritis. Little pharmacological evidences support this folk use except for previous in vitro study that reported significant inhibition of protein denaturation.

AIM OF THE STUDY

The study aims at providing new in vivo evidence on antiarthritic activity of P. peruviana fruits in vivo that justifies its traditional use through mechanism-based experiment.

MATERIAL AND METHODS

Inhibition of inflammatory mediators is considered one of the key treatments to alleviate painful symptoms of rheumatoid arthritis (RA). Anti-inflammatory activity was assessed against COX-1 and COX-2 activity in vitro. Serum TNFα, IL-1β and IL-6 were traced using in vivo model of adjuvant-induced arthritis. Gross/inflammatory changes in rat paw, relative mass indices of spleen and liver were further investigated together with joint tissue histoarchitecture. Seven metabolites from different phytochemical classes, that were previously reported in P. peruviana fruit, were evaluated in silico against TNF-α target protein (PDB ID: 2AZ5) to assess their inhibitory effect. This was followed by assessment of their drug-likeness based on Lipinski's rule according to their physicochemical and pharmacokinetic properties.

RESULTS

High dose of extract (E-1000 mg) improved adjuvant-induced cachexia and attenuated immune-inflammatory responses in paw and serum parameters, with equipotent effect to MTX, in addition to minimal side effect profile on spleen and liver. Histopathological study of knee joint tissues confirmed dose-dependent improvement in arthritic groups treated with P. peruviana fruit extracts. The insilico study recommended steroidal lactones withaperuvin E/C and hydroxywithanolide E as promising lead compounds for inhibiting TNF enzyme as evidenced by docking scores of 6.301, 5.488 and 5.763 kcal/mol, respectively, fitting as well the Lipinski's rule of drug likeness.

CONCLUSION

The study provided novel approach that rationalize folk use of P. peruviana fruit in treatment of arthritis.

Abdominal vagus nerve stimulation alleviates collagen-induced arthritis in rats

Rheumatoid arthritis (RA) is a chronic, autoimmune inflammatory disease. Despite therapeutic advances, a significant proportion of RA patients are resistant to pharmacological treatment. Stimulation of the cervical vagus nerve is a promising alternative bioelectric neuromodulation therapeutic approach. However, recent clinical trials show cervical vagus nerve stimulation (VNS) was not effective in a significant proportion of drug resistant RA patients. Here we aim to assess if abdominal vagus nerve stimulation reduces disease severity in a collagen-induced arthritis (CIA) rat model. The abdominal vagus nerve of female Dark Agouti rats was implanted and CIA induced using collagen type II injection. VNS (1.6 mA, 200 μs pulse width, 50 μs interphase gap, 27 Hz frequency) was applied to awake freely moving rats for 3 h/day (days 11-17). At 17 days following the collagen injection, unstimulated CIA rats (n = 8) had significantly worse disease activity index, tumor necrosis factor-alpha (TNF-α) and receptor activator of NFκB ligand (RANKL) levels, synovitis and cartilage damage than normal rats (n = 8, Kruskal-Wallis: P < 0.05). However, stimulated CIA rats (n = 5-6) had significantly decreased inflammatory scores and ankle swelling (Kruskal-Wallis: P < 0.05) compared to unstimulated CIA rats (n = 8). Levels of tumor necrosis factor-alpha (TNF-α) remained at undetectable levels in stimulated CIA rats while levels of receptor activator of NFκB ligand (RANKL) were significantly less in stimulated CIA rats compared to unstimulated CIA rats (P < 0.05). Histopathological score of inflammation and cartilage loss in stimulated CIA rats were no different from that of normal (P > 0.05). In conclusion, abdominal VNS alleviates CIA and could be a promising therapy for patients with RA.

Flavored Food Additives on the Leaves of Piper betle L.: A Human Health Perspective

Natural products and traditional ethnomedicines are of great effect in therapeutics. Such types of medicine have been practiced in certain areas of the world to treat different health conditions. This pilot investigation aims to review the cumulative health effect of addendums used in betel quid such as areca nut, lime, and tobacco-associated betel quid chewing and without tobacco-associated chewing. This review shows that betel leaf extract and its essential oil could inhibit growth of microbes and damage different gram-positive and gram-negative bacteria as well as various fungus species. Some studies concluded that the combination of Piper leaves essential oil with antibiotics have potential effect on oral microorganisms. Long-term consumption of betel quid with tobacco is known to cause cancer, chromosomal aberrations, and pharynx tumors. However, consumption of betel leaf without tobacco has health benefits because of ethnomedicinal properties. Its essential is oil utilized as raw material for perfumes and mouth fresheners manufacturing. Scientific researches on this plant revealed that it possesses many beneficial activities to be used for developing novel drugs. However, compounds of betel leaves have beneficial natural antioxidant. Chewing and intake of leaves have effect on moving parts of salivary gland which is the main step of digestion. Its components also act as heartbeat regulators in relaxing the blood vessels to reduce hypertension. So this review discussed the natural compounds of betel leaves which is used as traditional medicine to further develop drug discovery.

Targeting inflammation and redox perturbations by lisinopril mitigates Freund's adjuvant-induced arthritis in rats: role of JAK-2/STAT-3/RANKL axis, MMPs, and VEGF

BACKGROUND

Cardiovascular disorders are major complications of rheumatoid arthritis (RA). Hence, finding effective agents that can target RA progression and its cardiovascular consequences is demanding. The present work aimed to explore the potential of lisinopril, an angiotensin-converting enzyme inhibitor, to mitigate adjuvant's-induced arthritis with emphasis on the pro-inflammatory signals, articular degradation cues, and angiogenesis alongside JAK-2/STAT-3 and Nrf2/HO-1 pathways.

METHODS

Lisinopril (10 mg/kg/day) was administered by oral gavage for 3 weeks and the target signals were examined by biochemical assays, ELISA, histopathology, immunoblotting, and immunohistochemistry.

RESULTS

Lisinopril attenuated the progression of arthritis as proven by lowering paw edema, arthritic index, and gait scores alongside diminishing the immune-cell infiltration/aberrant histopathology in the dorsal pouch lining. These favorable actions were associated with curtailing the production of inflammatory cytokines (TNF-α, IL-6, IL-1β, and IL-17) and the pro-inflammatory angiotensin II alongside upregulating the anti-inflammatory angiotensin-(1-7) in the hind paw of arthritic rats. At the molecular level, lisinopril inhibited the upstream JAK-2/STAT-3 pathway by downregulating the protein expression of p-JAK-2/total JAK-2 and p-STAT-3/total STAT-3 ratio and the nuclear levels of NF-κBp65. Meanwhile, lisinopril curbed the downstream cartilage degradation signals matrix metalloproteinases (MMP-3 and MMP-9) and the bone erosion cue RANKL. Equally important, the protein expression of the angiogenesis signal VEGF was downregulated in the hind paw/dorsal lining. With respect to oxidative stress, lisinopril suppressed the paw lipid peroxides and boosted GSH and Nrf-2/HO-1 pathway.

CONCLUSION

Lisinopril attenuated adjuvant-induced arthritis via inhibition of inflammation, articular degradation cues, and angiogenesis.

Role of oxidative stress in induction of trans-differentiation of neutrophils in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disorder whose etiopathology involves an interplay between genetic and environmental factors, with oxidative stress being a key contributory factor. This study aimed to establish the impact, if any, of an oxidative, pro-inflammatory milieu upon trans-differentiation of neutrophils and disease progression. In the synovial fluid (SF) and peripheral blood sourced from patients with RA (n = 40) along with healthy controls (n = 25), the proportion of neutrophil-dendritic (N-DC) cell hybrids, i.e. CD66b⁺/CD83⁺ was characterized in terms of their antigen presentation (HLA-DR, CD80, andCD86) and cell adhesion and migration (ICAM-1, VCAM-1, and CD62L) properties, along with their ability to generate reactive oxygen species (ROS). In the SF of RA cases, the raised levels of circulating and intra-neutrophilic pro-inflammatory cytokines/chemokines were accompanied by an enhanced proportion of CD66b⁺ neutrophils, that co-expressed features of antigen presenting cells (APCs) namely CD83, HLA-DR, CD80, CD86, ICAM-1, VCAM-1, and decreased CD62L. These N-DCs as compared to canonical neutrophils demonstrated a higher generation of ROS, and their frequency positively correlated with disease activity score (DAS28). An ex-vivo functional assay validated that oxidative stress supported trans-differentiation and could be attenuated by a free radical scavenger. Taken together, the pro-inflammatory microenvironment in the SF of patients with RA coupled with a higher generation of ROS promoted the trans-differentiation of neutrophils into N-DCs, suggesting the inclusion of anti-oxidants as an add-on therapeutic strategy to limit trans-differentiation.

Suppression of NF-κB signaling by ECN in an arthritic model of inflammation

BACKGROUND

The 7β-(3-ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranone (ECN), a sesquiterpenoid isolated from the Tussilago farfara Linneaus (Asteraceae), was evaluated against acute Carrageenan and chronic complete Freund's adjuvant (CFA)-induced arthritis in mice.

METHODS

Acute and chronic arthritis were induced by administering Carrageenan and CFA to the intraplantar surface of the mouse paw. Edema, mechanical allodynia, mechanical hyperalgesia, and thermal hyperalgesia were assessed in the paw. Similarly, histological and immunohistological parameters were assessed following arthritis induced by CFA. Antioxidants, inflammatory cytokines, and oxidative stress markers were also studied in all the treated groups.

RESULTS

The ECN treatment significantly attenuated edema in the paw and elevated the nocifensive threshold following induction of this inflammatory model. Furthermore, ECN treatment markedly improved the arthritis index and distress symptoms, while attenuating the CFA-induced edema in the paw. ECN treatment also improved the histological parameters in the paw tissue compared to the control. At the same time, there was a significant reduction in edema and erosion in the ECN-treated group, as measured by radiographic analysis. Using the Comet's assay, we showed that ECN treatment protected the DNA from chronic CFA-induced arthritis. Immunohistochemistry analysis showed a marked decrease in the expression level of p-JNK (phosphorylated C-Jun N-terminal kinase), NF-κB (Nuclear factor-kappa B), COX-2 (Cyclooxygenase-2), and TNF-α (Tumour necrosis factor-alpha) compared to the CFA-treated group. Biophysical analysis involving molecular docking, molecular dynamics simulations, and binding free energies of ECN were performed to explore the underlying mechanism.

CONCLUSION

ECN exhibited significant anti-inflammatory and anti-arthritic activity against Carrageenan and CFA-induced models.

Repurposing monoamine oxidase inhibitors (MAOI) for the treatment of rheumatoid arthritis possibly through modulating reactive oxidative stress mediated inflammatory cytokines

Monoamine oxidase inhibitors (MAOI) are presently used to treat depression, parkinsonian, and other psychiatric disorders. The present study was aimed to repurpose the use of MOAI in Rheumatoid Arthritis (RA). The animal model of RA was developed using collagen type II (CII) in Freund's complete adjuvant (FCA) followed by lipopolysaccharide (LPS) and a booster dose of CII in FCA. The effect of MAOI, Selegiline was evaluated whereas the indicators like paw thickness, arthritic score, and the splenic index were measured and compared with the standard drug Methotrexate. Further to explore the molecular mechanism, the expression of serum inflammatory cytokines (IL-6 and TNF-α), radiographical and histopathological study of hind paw were also checked and analyzed. Treatment with MAOI, Selegiline not only reduced the paw thickness, arthritic score, and the splenic index, but also greatly improved the inflammatory biochemical and hematologic parameters and improved the arthritis score. The serum level of IL-6 and TNF-α are considerably decreased dose dependently, however, the notable significant effect (**p < 0.01) observed at concentration of 30 mg/kg b.w. when the RA animals treated by Selegiline. Collectively, Selegiline improved the progression of RA possibly via decreased catecholamine breakdown at synovial fluid resulting decrease hydrogen peroxide (H₂O₂) generation and inhibition of pro-inflammatory cytokines in situ. Thus, the finding support and indicate the repurposing of MAOI for the treatment of RA meriting further studies on synovial monoamine oxidase as a new therapeutic target to design a new drug for RA.

Ethyl Acetate Fractions of Papaver rhoeas L. and Papaver nudicaule L. Exert Antioxidant and Anti-Inflammatory Activities

Abnormal inflammation and oxidative stress are involved in various diseases. Papaver rhoeas L. possesses various pharmacological activities, and a previously reported analysis of the anti-inflammatory effect of P. nudicaule ethanol extracts and alkaloid profiles of the plants suggest isoquinoline alkaloids as potential pharmacologically active compounds. Here, we investigated anti-inflammatory and antioxidant activities of ethyl acetate (EtOAc) fractions of P. nudicaule and P. rhoeas extracts in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. EtOAc fractions of P. nudicaule and P. rhoeas compared to their ethanol extracts showed less toxicity but more inhibitory activity against LPS-induced nitric oxide production. Moreover, EtOAc fractions lowered the LPS-induced production of proinflammatory molecules and cytokines and inhibited LPS-activated STAT3 and NF-κB, and additionally showed significant free radical scavenging activity and decreased LPS-induced reactive oxygen species and oxidized glutathione. EtOAc fractions of P. nudicaule increased the expression of HO-1, GCLC, NQO-1, and Nrf2 in LPS-stimulated cells and that of P. rhoeas enhanced NQO-1. Furthermore, metabolomic and biochemometric analyses of ethanol extracts and EtOAc fractions indicated that EtOAc fractions of P. nudicaule and P. rhoeas have potent anti-inflammatory and antioxidant activities, further suggesting that alkaloids in EtOAc fractions are potent active molecules of tested plants.

Role of oxidative stress in pathophysiology of rheumatoid arthritis: insights into NRF2-KEAP1 signalling

Rheumatoid arthritis is one of the most prevalent, chronic, inflammatory disorders involving multiple articular and extra-articular complications. Immune deregulation owing to a combinatorial network of cells, inflammatory components, degrading enzymes, angiogenetic factors, exhibiting pleiotropy, synergy, or redundancy, is a critical hallmark for synovial inflammatory milieu reasoning clinical heterogeneity and variability of the disease. As a prototype of autoimmune disease, the pathophysiology of rheumatoid arthritis has been linked to oxidative stress. However, the exact mechanism for these potential driving factors contributing to disease inception and perpetuation is yet elusive. Nuclear factor erythroid 2-related factor 2 - Kelch ECH associating protein 1 (Nrf2-Keap1) pathway, controlled via multifactorial regulation, functions as a ubiquitous, evolutionarily conserved intracellular defense mechanism. Nrf2-Keap1 signalling maintains homeostatic responses against a plethora of environmental or endogenous deviations in cellular growth, death, redox metabolism, inflammation, bone remodelling, detoxification, etc. Administration of antioxidants as an add-on pharmacotherapy along with conventional drugs has been elucidated as a better measure for disease management. Some of the most promising natural and synthetic redox-based therapeutic compounds function as either scavengers of reactive species, or inhibitors of their sources, or activators of an endogenous antioxidant system (Nrf2-Keap1). The present review focuses on the binomial "rheumatoid arthritis-oxidative stress", bringing insights into their pathophysiological interrelationships and Nrf2 signalling, as well as the implications of potential diagnostic oxidative stress biomarkers and therapeutic interventions directed for disease management in patients with rheumatoid arthritis.Highlights:RA has complex etiopathogenesis, evolving from multiple endogenous and exogenous factors with oxidative stress as a critical pathogenic signature.Oxidative damage and damaged compounds could serve as potent biomarkers for disease diagnosis, therapeutic response, and prognosis.One of the supreme cytoprotective signalling cascades, the Nrf2-Keap1 pathway has been known to elicit a protective effect against RA and various other autoimmune, inflammatory, degenerative disorders.Inclusion of natural and synthetic antioxidants has been encouraged by various studies for additional therapy to conventional drugs for better management of the disease.

Molecular insights into phytochemicals exhibiting anti-arthritic activity: systematic review : John Di Battista

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease with an unclear etiology causing severe inflammation, joint pain, and destruction that increases the chance of disability over time. Dysregulation of various immune signaling cascades regulates the formation of synovial hyperplasia and pannus formation. Imbalance in cytokine levels, predominantly proinflammatory cytokines like TNF-α, IL-1, IL-6, IL-17, and IL-12p70 profoundly influences the disease's pathogenesis. Even though various strategies are adopted to treat arthritis, their side effects and cost limit their usage. This review discusses the multiple pathways involved in the pathogenesis of rheumatoid arthritis, provides a systematic analysis of various phytochemicals, and discusses their potential molecular targets in RA treatment.

METHODS

The literature mining was done from scientific databases such as PubMed, Europe PMC, Web of Science, Scopus, etc. The terminologies used for literature mining were Rheumatoid arthritis, phytochemicals, cell signaling pathways, molecular mechanism, etc. RESULTS: NF-κB, MAPKs, and JAK-STAT are the key pathways potentially targeted for RA treatment. However, specific susceptible pathways and potential targets remain unexplored. Besides, the phytochemicals remain an immense source to be exploited for the effective treatment of RA, overcoming the demerits of the conventional strategies. Various in vitro and in vivo findings suggest that polyphenols and flavonoids effectively treat RA conditions overcoming the demerits, such as limitations in usage and toxicity. The phytochemicals should be explored in par with the pathological mechanisms with all the available targets to determine their therapeutic efficacy. Through the established therapeutic efficacy, phytochemicals can help developing therapeutics that are safe and efficacious for RA treatment.

The Role of Natural Products in Rheumatoid Arthritis: Current Knowledge of Basic In Vitro and In Vivo Research

Rheumatoid arthritis (RA) is an autoimmune disorder affecting a vast variety of the population. The onset of RA as well as the development of systematic immunization is affected by both genetic and environmental risk factors. This review aims to point out the role of natural products in the management of RA, focusing on the reports of basic research (in vitro and animal studies) emphasizing the antioxidant and anti-inflammatory properties considered in the field of RA. A systematic screening of the relevant literature was carried out on PubMed, Google Scholar, and Scopus with the following criteria: publication date, 2015-2020; language, English; study design, in vitro or animal models; and the investigation of one or several natural products in the context of RA, including, when available, the molecular mechanisms implicated. A total of 211 papers were initially obtained and screened. In vitro and animal studies referring to 20 natural products and 15 pure compounds were ultimately included in this review. The outcomes of this work provide an overview of the methods employed in basic research over the past five years, with emphasis on the limitations presented, while demonstrating the potential benefits of utilizing natural products in the management of RA as supported by in vitro and animal studies.

Anti-Inflammatory and Antioxidant Effects of Carpesium cernuum L. Methanolic Extract in LPS-Stimulated RAW 264.7 Macrophages

A hypernomic reaction or an abnormal inflammatory process could cause a series of diseases, such as cardiovascular disease, neurodegeneration, and cancer. Additionally, oxidative stress has been identified to induce severe tissue injury and inflammation. Carpesium cernuum L. (C. cernuum) is a Chinese folk medicine used for its anti-inflammatory, analgesic, and detoxifying properties. However, the underlying molecular mechanism of C. cernuum in inflammatory and oxidative stress conditions remains largely unknown. The aim of this study was to examine the effects of a methanolic extract of C. cernuum (CLME) on lipopolysaccharide- (LPS-) induced RAW 264.7 mouse macrophages and a sepsis mouse model. The data presented in this study indicated that CLME inhibited LPS-induced production of proinflammatory mediators such as nitric oxide (NO) and prostaglandin E₂ (PGE₂) in RAW 264.7 cells. CLME treatment also reduced reactive oxygen species (ROS) generation and enhanced the expression of heme oxygenase-1 (HO-1) protein in a dose-dependent manner in the LPS-stimulated RAW 264.7 cells. Moreover, CLME treatment abolished the nuclear translocation of nuclear factor-κB (NF-κB), enhanced the activation of nuclear factor-erythroid 2 p45-related factor 2 (Nrf2), and reduced the expression of extracellular signal-related kinase (ERK) and ERK kinase (MEK) phosphorylation in LPS-stimulated RAW 264.7 cells. These outcomes implied that CLME could be a potential antioxidant and anti-inflammatory agent.

Generation of a robust model for inducing autoimmune arthritis in Sprague Dawley rats

INTRODUCTION

The prerequisite for any experimental model in animals is similarity with the human disease, uniformity in disease severity and incidence. In antigen-induced arthritis models it is generally recognized that the major limitation is inconsistency in terms of incidence and severity. As access to strains like DBA/1 mice or Lewis rats is difficult for resource restrained laboratories, this study aimed to establish a robust and reproducible animal model of rheumatoid arthritis (RA).

METHODS

Multiple approaches were undertaken for inducing arthritis in Sprague Dawley (SD) and Wistar rats using complete Freund's adjuvant (CFA), collagen type II (CII) emulsion, or different combinations of CII with low dose CFA along with lipopolysaccharide (LPS). The development of arthritis was evaluated by measuring paw edema, arthritis score, body weight, splenic index, histopathology and radiography of paw tissues.

RESULTS

The combination of CII with low dose CFA and one injection of LPS resulted in 100% incidence of arthritis with disease severity ranging from moderate to severe and results were corroborated by histopathology and radiography.

DISCUSSION

In a head-to-head comparison between SD and Wistar rats, the disease profile was better sustained and consistent in SD rats, and the use of CII with low dose CFA and LPS induced features akin to human RA. Taken together, a reproducible model of arthritis was established which can be replicated in any laboratory with limited resources.

Norisoboldine, a natural aryl hydrocarbon receptor agonist, alleviates TNBS-induced colitis in mice, by inhibiting the activation of NLRP3 inflammasome

Although the etiology of inflammatory bowel disease is still uncertain, increasing evidence indicates that the excessive activation of NLRP3 inflammasome plays a major role. Norisoboldine (NOR), an alkaloid isolated from Radix Linderae, has previously been demonstrated to inhibit inflammation and IL-1β production. The present study was to examine the effect of NOR on colitis and the underlying mechanism related to NLRP3 inflammasome activation. Our results showed that NOR alleviated colitis symptom in mice induced by 2, 4, 6-trinitrobenzene sulfonic acid (TNBS). Moreover, it significantly reduced expressions of cleaved IL-1β, NLRP3 and cleaved Caspase-1 but not ASC in colons of mice. In THP-1 cells, NOR suppressed the expressions of NLRP3, cleaved Caspase-1 and cleaved IL-1β but not ASC induced by lipopolysaccharide (LPS) and adenosine triphosphate (ATP). Furthermore, NOR could activate aryl hydrocarbon receptor (AhR) in THP-1 cells, inducing CYP1A1 mRNA expression, and promoting dissociation of AhR/HSP90 complexes, association of AhR and ARNT, AhR nuclear translocation, XRE reporter activity and binding activity of AhR/ARNT/XRE. Both siAhR and α-naphthoflavone (α-NF) markedly diminished the inhibition of NOR on NLRP3 inflammasome activation. In addition, NOR elevated Nrf2 level and reduced ROS level in LPS- and ATP-stimulated THP-1 cells, which was reversed by either siAhR or α-NF treatment. Finally, correlations between activation of AhR and attenuation of colitis, inhibition of NLRP3 inflammasome activation and up-regulation of Nrf2 level in colons were validated in mice with TNBS-induced colitis. Taken together, NOR ameliorated TNBS-induced colitis in mice through inhibiting NLRP3 inflammasome activation via regulating AhR/Nrf2/ROS signaling pathway.

Protective effects of N(2)‑L‑alanyl‑L‑glutamine mediated by the JAK2/STAT3 signaling pathway on myocardial ischemia reperfusion

To explore the protective effect of N(2)-L-alanyl-L-glutamine (NLAG) on myocardial ischemia-reperfusion injury (IRI), and observe the influence of NLAG on the Janus activated kinase signal transducer 2 and activator of transcription 3 (JAK2/STAT3) signaling pathway‑associated molecules. Wistar rats were randomly divided into three groups: Sham, IRI and NLAG. In the IRI rat model, the cardiac hemodynamics, the maximum rate of left ventricular pressure (+dP/dtmax) and the left ventricular end‑diastolic pressure (LVDP) were recorded. Hematoxylin‑eosin and Masson staining were used to detect myocardial histological changes. The levels of plasma interleukin (IL)‑1β and ‑6, tumor necrosis factor (TNF)‑α, lactase dehydrogenase (LDH), troponin (cTn)I, creatine kinase (CK), heart type fatty acid binding protein (hFABP), malondialdehyde (MDA) and succinate dehydrogenase (SDH) were determined with ELISA. The protein expression levels of B‑cell lymphoma (Bcl)‑2, Bcl2‑associated X protein (Bax), Caspase‑3, JAK2, phosphorylated (p)‑JAK2, STAT3 and p‑STAT3 were detected by western blot analysis. The IRI model demonstrated notable myocardial injury; myocardial cells were arranged disorderly with some nuclei disappearing, and cardiac muscular fibers were degenerated. Following 60 min of reperfusion, LVDP, HR and +dP/dtmax were 31.3±4.53 mmHg, 239.17±8.45 beats/min and 615.17 mmHg/sec, respectively. Compared with the Sham group, the levels of LDH, cTnI, CK, hFABP release, inflammatory factors (IL‑1β, IL‑6 and TNF‑α) and oxygen free radical (MDA and SDH) levels were increased in the IRI group. In the NLAG group, myocardial injury was improved, the concentrations of LDH, cTnI, CK, hFABP, IL‑1β, IL‑6, TNF‑α, MDA were decreased, and SDH release was increased compared with the IRI group. In addition, NLAG significantly increased Bcl‑2, JAK2, p‑JAK2, STAT3 and p‑STAT3 protein expression, and decreased Bax protein expression compared with the IRI group. In conclusion, myocardial ischemia‑reperfusion can lead to myocardial cell apoptosis and myocardial injury and NLAG attenuates the IRI‑induced mitochondrial oxidative stress injury and apoptosis by activating the JAK2/STAT3 signaling pathway, thus exerting protective effects against IRI.

MiR-873-5p regulated LPS-induced oxidative stress via targeting heme oxygenase-1 (HO-1) in KGN cells

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women.