MSU-induced Gouty Arthritis Research Articles

Regulation of TRPV1 channel in monosodium urate-induced gouty arthritis in mice.

The transient receptor potential vanilloid subtype 1 (TRPV1) channel is considered to play an important regulatory role in the process of pain. The purpose of this study is to observe the change characteristics of TRPV1 channel in MSU-induced gouty arthritis and to find a new target for clinical treatment of gout pain. Acute gouty arthritis was induced by injection of monosodium urate (MSU) crystals into the ankle joint of mice. The swelling degree was evaluated by measuring the circumference of the ankle joint. Mechanical hyperalgesia was conducted using the electronic von Frey. Calcium fluorescence and TRPV1 current were recorded by applying laser scanning confocal microscope and patch clamp in dorsal root ganglion (DRG) neurons, respectively. MSU treatment resulted in significant inflammatory response and mechanical hyperalgesia. The peak swelling degree appeared at 12h, and the minimum pain threshold appeared at 8h after MSU treatment. The fluorescence intensity of capsaicin-induced calcium response and TRPV1 current were increased in DRG cells from MSU-treated mice. The number of cells that increased calcium response after MSU treatment was mainly distributed in small-diameter DRG cells. However, the action potential was not significantly changed in small-diameter DRG cells after MSU treatment. These findings identified an important role of TRPV1 in mediating mechanical hyperalgesia in MSU-induced gouty arthritis and further suggest that TRPV1 can be regarded as a potential new target for the clinical treatment of gouty arthritis.

The Anti-Inflammatory and Uric Acid Lowering Effects of Si-Miao-San on Gout.

BackgroundSi-Miao-San (SMS) is a well-known traditional Chinese medicine. This study aims to evaluate the anti-inflammatory effects of SMS on gouty arthritis and its potential mechanism of action.MethodsThe effects and mechanism of SMS were evaluated in monosodium urate (MSU)-treated mice or macrophages. The expression of cytokines and PI3K/Akt was analyzed using real-time PCR and Western blotting analyses. Macrophage polarization was assessed with immunofluorescence assays, real-time PCR, and Western blotting. Mass spectrometry was used to screen the active ingredients of SMS.ResultsPretreatment with SMS ameliorated MSU-induced acute gouty arthritis in mice with increased PI3K/Akt activation and M2 macrophage polarization in the joint tissues. In vitro, SMS treatment significantly inhibited MSU-triggered inflammatory response, increased p-Akt and Arg-1 expression in macrophages, and promoted M2 macrophage polarization. These effects of SMS were inhibited when PI3K/Akt activation was blocked by LY294002 in the macrophages. Moreover, SMS significantly reduced serum uric acid levels in the hyperuricemia mice. Using mass spectrometry, the plant hormones ecdysone and estrone were detected as the potentially effective ingredients of SMS.ConclusionSMS ameliorated MSU-induced gouty arthritis and inhibited hyperuricemia. The anti-inflammatory mechanism of SMS may exert anti-inflammatory effects by promoting M2 polarization via PI3K/Akt signaling. Ecdysone and estrone might be the potentially effective ingredients of SMS. This research may provide evidence for the application of SMS in the treatment of gout.

MiR-192-5p suppresses M1 macrophage polarization via epiregulin (EREG) downregulation in gouty arthritis

Gouty arthritis (GA) is a chronic inflammatory disease characterized by the deposition of monosodium urate (MSU) crystals within joints. MiR-192-5p is shown to be low-expressed in GA patients. However, the potential mechanism involving miR-192-5p in GA remains unclear. In the current study, a significant reduction in miR-192-5p and an increase in epiregulin (EREG) were observed in serum of GA patients, suggesting that miR-192-5p and EREG were involved in the pathogenic process of GA. A mouse GA model was established via 0.5 mg/20 μL MSU crystal administration. To investigate the effect of miR-192-5p on GA, mice were injected with miR-192-5p agomir or NC agomir before modeling. We found that miR-192-5p overexpression induced by miR-192-5p agomir reduced EREG expression, attenuated ankle joint swelling and synovial inflammatory cell infiltration and improved bone erosion in MSU-induced GA mice. MiR-192-5p decreased CD16/32+ (M1 marker) macrophages, but increased CD206 (M2 marker) expression in synovium of GA models. In vitro, RAW264.7 macrophages were stimulated with miR-192-5p mimic or NC mimic under IFNγ plus LPS-stimulated M1 polarization condition. MiR-192-5p reduced the release of inflammatory cytokines TNF-α and IL-1β, decreased iNOS expression, and inhibited CD16/32 expression, indicating the blockade of M1 macrophage activation. Luciferase reporter system revealed the target interaction between miR-192-5p and EREG. Further rescue experiments demonstrated that EREG overexpression partly reversed the inhibitory role of miR-192-5p on M1 macrophage polarization manifested by elevated iNOS and CD16/32 levels. Collectively, miR-192-5p ameliorates inflammatory response in GA by inhibiting M1 macrophage activation via inhibiting EREG protein.

β-Caryophyllene Ameliorates MSU-Induced Gouty Arthritis and Inflammation Through Inhibiting NLRP3 and NF-κB Signal Pathway: In Silico and In Vivo.

Gouty arthritis serves as an acute reaction initiated by the deposition of monosodium urate (MSU) crystals around the joints. In this study, the anti-inflammatory effects of phytochemical β-caryophyllene on MSU crystal-induced acute gouty arthritis in vivo and in silico were explored. Through bioinformatics methods and molecular docking, it screened the specific influence pathway of β-caryophyllene on gout. Certain methods including enzyme-linked immunosorbent assay, western blotting, and immunohistochemical staining were adopted to quantify. β-caryophyllene significantly reduced inflammation and function of ankle joints in MSU Crystals-induced gouty arthritis rats, while decreasing serum cytokine levels. Furthermore, it inhibited the expressions of NLRP3, Caspase-1, ASC, TLR4, MyD88, p65, and IL-1β in the synovial tissue so as to reduce inflammation and protect ankle joints’ function. A new research approach in which β-caryophyllene treatment to acute attacks of gout is provided through the research results.

Pyroptosis inhibition alleviates potassium oxonate- and monosodium urate-induced gouty arthritis in mice.

Pyroptosis has been found implicated in several diseases, however, whether it was involved in gouty arthritis remained unclear. Our study was performed to uncover the role of pyroptosis in gouty arthritis based on a mice model. Mouse gouty arthritis model was established by injections of potassium oxonate (PO), monosodium urate (MSU) and pyroptosis suppressor disulfiram. The diameter of the ankle joints was measured, and ankle joints morphology was observed with hematoxylin-eosin (H&E) staining. Uric acid, creatinine and blood urea nitrogen (BUN) concentrations were measured, while cytokines level and xanthine oxidase (XOD) activity were quantified. Relative pyroptosis markers expressions were determined using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot as needed. In mouse model, PO and MSU injections cause damage to right ankle, increase the root thickness ratio and uric acid, creatinine and BUN levels in serum and decrease the uric acid and creatinine levels in urine. Also, under PO and MSU treatment, up-regulated XOD activity, inflammatory cytokines levels and pyroptosis markers expressions are observed. Negative regulation of mice injury by disulfiram treatment is also observed. Pyroptosis inhibition might alleviate PO- and MSU-induced gouty arthritis, providing possible therapeutic strategies for gouty arthritis.

Modulations of Nav1.8 and Nav1.9 Channels in Monosodium Urate-Induced Gouty Arthritis in Mice.

The aim of the present study was to observe the changes of TTX-R, Nav1.8, and Nav1.9 Na+ currents in MSU-induced gouty arthritis mice, and to explore the possibility of Nav1.8 and Nav1.9 channels as potential targets for gout pain treatment. Acute gouty arthritis was induced by monosodium urate (MSU) in mice. Swelling degree was evaluated by measuring the circumference of the ankle joint. Mechanical allodynia was assessed by applying the electronic von Frey. Na+ currents were recorded by patch-clamp techniques in acute isolated dorsal root ganglion (DRG) neurons. MSU treatment significantly increased the swelling degree of ankle joint and decreased the mechanical pain threshold. The amplitude of TTX-R Na+ current was significantly increased and reached its peak on the 4th day after injection of MSU. For TTX-R Na+ channel subunits, Nav1.8 current density was significantly increased, but Nav1.9 current density was markedly decreased after MSU treatment. MSU treatment shifted the steady-state activation curves of TTX-R Na+ channel, Nav1.8 and Nav1.9 channels, and the inactivation curves of TTX-R Na+ channel and Nav1.8 channels to the depolarizing direction, but did not affect the inactivation curve of Nav1.9 channel. Compared with the normal group, the recovery of Nav1.8 channel was faster, while that of Nav1.9 channel was slower. The recovery of TTX-R Na+ channel remained unchanged after MSU treatment. Additionally, MSU treatment increased DRG neurons excitability by reducing action potential threshold. Nav1.8 channel, not Nav1.9 channel, may be involved in MSU-induced gout pain by increasing nerve excitability.

Curcumin analogue AI-44 alleviates MSU-induced gouty arthritis in mice via inhibiting cathepsin B-mediated NLRP3 inflammasome activation

NOD-like receptors (NLRs), as a part of intracellular pattern recognition receptors (PRR), are important regulators in innate immune system. The NLRP3 inflammasome which is a member of NLRs has been linked to several human inflammatory diseases. Gouty arthritis is triggered when the deposition of monosodium urate (MSU) crystals in joints induces acute inflammation characterized by the recruitment of macrophages and neutrophils. In this study, we explored the curcumin analogue AI-44 alleviated the gouty arthritis in mice via suppressing MSU engaging NLRP3 inflammasome activation. Furthermore, we demonstrated that AI-44 inhibited the interaction of cathepsin B and NLRP3 to prevent the activation of NLRP3 inflammasome. Moreover, we found AI-44 inhibited the enzyme activity of cathepsin B and bound to the key residue E122 in cytoplasm but not in lysosome. Collectively, these data suggest that AI-44 is a novel drug candidate for the treatment of gouty arthritis through targeting cathepsin B and inhibiting NLRP3 inflammasome activation.

Zisheng Shenqi Decoction Ameliorates Monosodium Urate-Mediated Gouty Arthritis in Rats via Promotion of Autophagy through the AMPK/mTOR Signaling Pathway.

Gouty arthritis (GA) is an inflammatory disease owing to the accumulation of monosodium urate (MSU) in joints, leading to redness and burning pain. In this study, the effect of Zisheng Shenqi Decoction (ZSD) on a rat model of MSU-induced GA was investigated. ZSD obviously diminished the right paw thickness, the degree of the swelling of the paw, and the infiltration of the inflammatory cell, as well as cartilage erosion, and widened the joint space in MSU-treated rats. Besides, MSU remarkably elevated the release of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and IL-18; however, ZSD treatment dose dependently lowered these levels and resulted in a significant decrease in articular elastase activity. Also, ZSD administration increased the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) but declined malondialdehyde (MDA) and nitrogen monoxide (NO) contents. Importantly, western blotting analysis revealed that NOD-like receptor protein 3 (NLRP3), cleaved caspase-1, IL-1β, nuclear factor-E2-related factor 2 (Nrf2) in the cytoplasm, phosphorylated mammalian target of rapamyclin (p-mTOR), and p62 expressions were downregulated, whereas the levels of nuclear Nrf2, phosphorylated AMP-activated protein kinase (p-AMPK), Beclin-1, and LC3II/I were upregulated by ZSD. Immunofluorescence assay indicated that ZSD evidently promoted nuclear translocation of LC3. Taken together, ZSD inhibited inflammation and oxidative stress and facilitated autophagy through the activation of the AMPK pathway and suppression of the mTOR signaling pathway, demonstrating its potential for preventing and curing GA.

Celastrol ameliorates Propionibacterium acnes/LPS-induced liver damage and MSU-induced gouty arthritis via inhibiting K63 deubiquitination of NLRP3

BackgroundCelastrol, a pentacyclic triterpenoid quinonemethide isolated from several spp. of Celastraceae family, exhibits anti-inflammatory activities in a variety of diseases including arthritis. PurposeThis study aims to investigate whether the inhibition of NLRP3 inflammasome is engaged in the anti-inflammatory activities of celastrol and delineate the underlying mechanism. MethodsThe influence of celastrol on NLRP3 inflammasome activation was firstly studied in lipopolysaccharide (LPS)-primed mouse bone marrow-derived macrophages (BMDMs) and phorbol 12-myristate 13-acetate (PMA)-primed THP-1 cells treated with nigericin. Reconstituted inflammasome was also established by co-transfecting NLRP3, ASC, pro-caspase-1 and pro-IL-1β in HEK293T cells. The changes of inflammasome components including NLRP3, ASC, pro-caspase-1/caspase-1 and pro-IL-1β/IL-1β were examined by enzyme-linked immunosorbent assay (ELISA), western blotting and immunofluorescence. Furthermore, Propionibacterium acnes (P. acnes)/LPS-induced liver injury and monosodium urate (MSU)-induced gouty arthritis in mice were employed in vivo to validate the inhibitory effect of celastrol on NLRP3 inflammasome. ResultsCelastrol significantly suppressed the cleavage of pro-caspase-1 and pro-IL-1β, while not affecting the protein expressions of NLRP3, ASC, pro-caspase-1 and pro-IL-1β in THP-1 cells, BMDMs and HEK293T cells. Celastrol suppressed NLRP3 inflammasome activation and alleviated P. acnes/LPS-induced liver damage and MSU-induced gouty arthritis. Mechanism study revealed that celastrol could interdict K63 deubiquitination of NLRP3, which may concern interaction of celastrol and BRCA1/BRCA2-containing complex subunit 3 (BRCC3), and thereby prohibited the formation of NLRP3, ASC and pro-caspase-1 complex to block the generation of mature IL-1β. ConclusionCelastrol suppresses NLRP3 inflammasome activation in P. acnes/LPS-induced liver damage and MSU-induced gouty arthritis via inhibiting K63 deubiquitination of NLRP3, which presents a novel insight into inhibition of celastrol on NLRP3 inflammasome and provides more evidences for its application in the therapy of inflammation-related diseases.

Preventive effect of dioscin against monosodium urate-mediated gouty arthritis through inhibiting inflammasome NLRP3 and TLR4/NF-κB signaling pathway activation: an in vivo and in vitro study.

Monosodium urate (MSU)-mediated inflammation is closely related to gouty arthritis (GA). Dioscin, an active ingredient, has been reported to possess anti-inflammatory property. Nevertheless, the role of dioscin in GA and the underlying mechanism have not been fully understood. In the present study, we investigated the anti-inflammatory effect of dioscin on MSU-induced GA through in vivo and in vitro experiments. Histopathological analysis showed that dioscin alleviated the severity of GA concomitant with the lowered uric acid and creatinine levels. Moreover, the increasing IL-1β, IL-6, and TNF-α levels induced by MSU were decreased via administration of dioscin in mice and human synoviocytes. Western blotting results suggested that dioscin inhibited the activation of NLRP3 through down-regulating the protein expressions of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), cleaved-caspase-1, as well as IL-1β. In addition, TLR4, myeloid differentiation primary response gene 88 (MyD88), p-IKKβ, p-p65, and NF-κB p65 in nuclei levels were significantly reduced by dioscin. Importantly, dioscin remarkably lowered the NF-κB p65-DNA activity in MSU-treated mice utilizing electrophoretic mobility shift assay (EMSA) analysis. Taken together, dioscin had a protective effect against MSU-initiated inflammatory response via repressing the production of inflammatory cytokines and the activation of inflammasome NLRP3 and TLR4/NF-κB signaling pathway. The above findings revealed that dioscin could be a potential drug for the treatment of GA.

Anti-inflammatory potential of the aqueous extract of Cyamopsis tetragonoloba against the MSU-induced arthritis in female Wistar albino rats

Objective: Gout is an acute inflammation with joint swelling and pain. Uric acid plays a major role in causing gouty arthritis. Crystal shaped uric acid was found in the joint fluid at the severe condition. Guar gum is an herbal product with numerous medical benefits and its botanical name is Cyamopsis tetragonoloba. This study aims to find the protective activity of Cyamopsis tetragonoloba against the MSU-induced gouty arthritis in female Wistar albino rats. Methods: The parameters like weight assessment, paw volume, biochemical parameters (urea, uric acid and creatinine), antioxidant activities and histopathological of paw have been analyzed. The animals have been divided into 5 groups as follows 1) normal control, 2) Monosodium Urate Crystal (MSU)-induced on 1st day, 3) MSU-induced and treated with 500 mg of Cyamopsis tetragonoloba, 4) MSU-induced and treated with 1000 mg of Cyamopsis tetragonoloba and 5) MSU-induced and treated with indomethacin. Results: Aqueous extract of Cyamopsis tetragonoloba has shown reduced paw volume, renal markers, lipid peroxidation and acid phosphatase, whereas it raised anti-oxidants levels and diminished the inflammation in rats paw bone. Conclusion: The aqueous seed extract of Cyamopsis tetragonoloba has shown good benefits against MSU-induced gouty arthritis. The molecular studies have to be studied to known this mechanism in treating the inflammation.

OP0133 PRECLINICAL EFFICACY OF R835, A NOVEL IRAK1/4 DUAL INHIBITOR, IN RODENT MODELS OF JOINT INFLAMMATION

Background:Interleukin receptor associated kinases (IRAK) 1 and 4 are kinases involved in Toll-Like Receptor (TLR) and Interleukin-1 Receptor (IL-1R) signaling pathways, which regulate innate immunity and inflammation. Dysregulation of IRAK1/4 signaling can lead to a variety of inflammatory conditions including rheumatoid and gouty arthritis. As a result, IRAK1/4 are promising therapeutic targets for rheumatic diseases (1). We have identified a potent and selective IRAK1/4 inhibitor, R835, that substantially suppressed the elevation of LPS (TLR4 agonist)-induced serum cytokines in healthy human volunteers in a recently completed phase 1 study.Objectives:The aim of our study was to investigate the effect of IRAK1/4 selective inhibition as a potential therapeutic approach for rheumatological diseases. We evaluated the inhibition by our clinical candidate, R835, on TLR-, IL-1R- and NLRP3 inflammasome-induced cytokine production, as well as in preclinical models of arthritis.Methods:The effect of R835 on TLR- or IL-1R-induced cytokine production was evaluated in vitro using THP-1, human primary endothelial cells and human primary dendritic cells. The activity of R835 on the NLRP3 inflammasome was also tested in vitro using THP-1 cells. The pharmacokinetic-pharmacodynamic relationship of R835 was evaluated in a mouse model of IL-1b-induced cytokine release. Mice were pre-treated orally with vehicle or R835 prior to challenge; serum cytokine and plasma compound levels were determined. The efficacy of IRAK1/4 inhibition by R835 in rodent models of joint inflammation was evaluated in a mouse model monosodium (MSU)-induced peritonitis, in rat model of MSU-induced gouty arthritis and in a rat model of collagen-induced arthritis (CIA).Results:In human cells, R835 blocked proinflammatory cytokine production in response to TLR, IL-1R and NLRP3 inflammasome activation. In mice, R835 dose-dependently decreased serum cytokines in response to administration of IL-1b. Mice pre-treated with R835 demonstrated dose-dependent reductions in MSU crystal-induced serum and peritoneal cytokine levels, as well as neutrophil influx in the peritoneal cavity. Prophylactic and therapeutic treatment with R835 also resulted in significant inhibition of MSU crystal-induced knee edema and pain in a rat model of human gouty arthritis. In the rat model of CIA, R835 blocked both onset and progression of disease, by reducing inflammation, cartilage degeneration and synovial inflammation.Conclusion:R835 is a promising clinical candidate for the treatment of a range of cytokine-driven rheumatological diseases. R835 has proven to have desirable pharmacokinetic properties, was well tolerated and suppressed LPS-induced serum cytokines in healthy volunteers in a recent phase 1 study.

A Traditional Clinic Chinese Medicine Prescription Qu-Zhuo-Tong-Bi (QZTB) Alleviates Gouty Arthritis in Model Rats.

Qu-Zhuo-Tong-Bi (QZTB) is an empirical traditional Chinese medicine prescription for treating acute gouty arthritis clinically without serious adverse effects in mainland China. However, the biochemical mechanism underlying the therapeutic action produced by QZTB treatment against acute gouty arthritis and the effect on recurrent attack remain unknown. In this study, we investigated the anti-inflammatory and analgesic effects of QZTB on acute gouty arthritis and the recurrent attack in rats, as well as the underlying mechanisms. The gouty arthritis model was established by intra-articular injection of monosodium urate (MSU) crystal suspension (2 mg/50 μL) into the right ankle joint of Sprague Dawley (SD) male rats. QZTB (500 mg/kg) and the positive control drug meloxicam were administrated by gavages twice a day for 7 days before, or 3 days after, first MSU injection in different experiments, respectively. The analgesic effects were evaluated by pain-like behaviors and hind paw mechanical withdrawal threshold testing. The anti-inflammatory activities were evaluated by ankle swelling measurement, histologic examination, NLRP3 inflammasome, and inflammatory cytokine expression. Western blot and quantitative real-time PCR were used to detect the protein and mRNA expressions of NLRP3. IL-1β and TNF-α level in the blood serum were detected by enzyme-linked immunosorbent assay (ELISA). QZTB can suppress ankle swelling and synovial inflammation in the MSU-induced gouty arthritis rat model. QZTB alleviated the acute attack and prevented the recurrent attack of gouty arthritis. In addition, QZTB treatment significantly decreased both mRNA and protein levels of NLRP3, as well as the production of IL-1 and TNF-α in the ankle joint of model rats. Taken together, these results suggest that QZTB may be a promising herbal formula for the prevention and treatment of gouty arthritis in humans.

Aqueous and Methanol Extracts of Paullinia pinnata (Sapindaceae) Improve Monosodium Urate-Induced Gouty Arthritis in Rat: Analgesic, Anti-Inflammatory, and Antioxidant Effects.

The profound modification of lifestyle and food habits has led to an important increase in the prevalence of gout. Unfortunately, there are current unmet needs for the treatment of this disease, prompting the search for new alternatives. Paullinia pinnata is a plant used to treat various diseases including arthritis. The present work aimed to investigate the antigouty activities of the aqueous (AEPP) and methanolic (MEPP) extracts of P. pinnata as well as their in vivo antioxidant properties. The gouty arthritis was induced by injecting 50 μl of monosodium urate (MSU, 100 mg/ml) in the left hind ankle of rats. P. pinnata extracts were administered orally at the doses of 100 and 200 mg/kg/day for 6 days, starting 24 h after MSU injection. Allopurinol 5 mg/kg/day was used as reference drug. Inflammation and hyperalgesia were daily monitored from 24 hours after treatment initiation and for the 6 consecutive days. Myeloperoxidase (MPO) quantification was done in collected synovial fluid. Nitrite oxide (NO), malondialdehyde (MDA), and superoxide dismutase (SOD) were evaluated in the spinal cord and the brain. The serum content of SOD was additionally quantified. AEPP and MEPP significantly (p < 0.001) reduce MSU-induced inflammation (22.41% to 93.65%) and hyperalgesia (33.33% to 64.44%) in both ankle and paw. AEPP and MEPP significantly (p < 0.001) reduce synovial MPO production with the percentage ranging from 76.30% to 85.19%. AEPP and MEPP significantly (p < 0.001) reduce serum, spinal, left and right hemispheres NO, and MDA and increase the SOD activity (p < 0.001). P. pinnata leaf extracts possess potent curative effects against MSU-induced gouty arthritis that combines analgesic, anti-inflammatory, and antioxidant activities. These findings support the use of P. pinnata leaves extracts in the treatment of gouty arthritis and further present the plant as a potent source of efficient antigouty medicine.

Anti-inflammatory and anti-osteoarthritis effect of Mollugo pentaphylla extract

Context: Mollugo pentaphylla L. (Molluginaceae) extract (MPE) has been reported to have anti-inflammatory effect on MSU-induced gouty arthritis in a mouse model.Objective: This study examined the anti-inflammatory activities of an MPE in vitro and anti-osteoarthritis effects on monosodium iodoacetate (MIA)-induced osteoarthritis (OA) in vivo.Materials and methods: The dried whole plants of M. pentaphylla were extracted with 70% ethanol under reflux. The anti-inflammatory effect of MPE was evaluated in vitro in lipopolysaccharide (LPS)-treated RAW264.7 cells. The anti-osteoarthritic effect of MPE was investigated in a Sprague–Dawley rat model of MIA-induced OA. Each seven male rats were orally administered MPE (75, 150 or 300 mg/kg) or the positive control drug indomethacin (1 mg/kg) 3 days before MIA injection and once daily for 11 days thereafter. After the treatment with MPE, no evidence of systemic adverse effects was observed in any study group.Results: MPE exhibited anti-inflammatory activity via inhibition of the production of NO (57.8%), PGE2 (97.1%) and IL-6 (93.2%) in LPS-treated RAW264.7 cells at 200 μg/mL. In addition, MPE suppressed IL-1β (60.9%), TNF-α (37.9%) and IL- 6 (40.9%) production and suppressed the synthesis of MMP-2, MMP-9 and COX-2 in the MIA-induced OA rat model.Conclusions: These results demonstrate that MPE exerts potent anti-inflammatory activities and protects cartilage in an OA rat model. This might be a potential candidate for therapeutic OA treatment.

Curcumin ameliorates monosodium urate-induced gouty arthritis through Nod-like receptor 3 inflammasome mediation via inhibiting nuclear factor-kappa B signaling.

Monosodium urate (MSU) crystals-induced inflammation is a key initiator in gouty arthritis. Curcumin is an active ingredient possessing anti-inflammatory efficacy. But the underlying mechanism is not fully understood and its effect on gouty arthritis remains elusive. We evaluated the effects of curcumin on cell viability in primary rat abdominal macrophages with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). Then supernatants of MSU crystals-stimulated cells were collected and subjected to enzyme-linked immunosorbent assay for checking the modulation of curcumin on interleukin (IL)-1β and tumor necrosis factor (TNF)-α. Meanwhile, cells were analyzed by using Western blot analysis and quantitative polymerase chain reaction (QPCR) to investigate the effects of curcumin on Nod-like receptor 3 (NLRP3) inflammasome/nuclear factor-kappa B (NF-κB) signaling. We also investigated the in vivo efficacy of curcumin with MSU-induced gouty arthritis rat models. Curcumin could reduce MSU crystals-induced IL-1β and TNF-α in vitro. Western blot analysis and QPCR results revealed that curcumin regulated the production of these cytokines by suppressing the expression of inflammasome key components, including NLRP3, caspase-1. Further studies showed that the suppressive efficacy of curcumin on inflammasome was mediated by inhibiting MSU-induced NF-κB signaling activation. Intraperitoneal administration of curcumin could ameliorate symptoms of MSU-induced gouty arthritis, including the joint circumference, infiltration of neutrophils in knee joints, and production of IL-1β, TNF-α, and elastase. Western blot analysis revealed that the levels of NLRP3, procaspase-1, caspase-1, pro-IL-1β, and IL-1β were downregulated by curcumin in vivo. These results indicated that curcumin could effectively ameliorate MSU crystal-induced gouty arthritis through NLRP3 inflammasome mediation via inhibiting NF-κB signaling both in vitro and in vivo, suggesting a promising active ingredient for the prevention and treatment of gouty arthritis.

Effects of Mollugo pentaphylla extract on monosodium urate crystal-induced gouty arthritis in mice

BackgroundGout is an inflammatory condition induced by the deposition of monosodium urate (MSU) crystals in joints and soft tissues, and it can lead to acute or chronic arthritis. MSU are pro-inflammatory stimuli that can initiate, amplify and sustain an intense inflammatory response. In this study, we evaluated the anti-inflammatory effect of an extract of Mollugo pentaphylla (MPE) on MSU-induced gouty arthritis in a mouse model.MethodAn MSU crystal suspension (4 mg/50 μL) was injected intradermally into the right paw. The mice were orally administered MPE (150 mg/kg or 300 mg/kg) or the positive control drug colchicine (1 mg/kg) 1 h before the MSU crystals were injected and then once daily for 3 days. The effects of MPE included inflammatory paw edema and pain upon weight-bearing activity, and we evaluated the inflammatory cytokine expression and paw tissue inflammation-related gene expression.ResultsMPE suppressed inflammatory paw edema and pain in the MSU-induced mice. MPE showed anti-inflammatory activity by inhibiting the production of TNF-α, interleukin (IL)-1β, NLRP3 inflammasome and NF-κB.ConclusionThese results suggest that MPE has potent anti-inflammatory activities and may be useful as a therapeutic agent against gouty arthritis.

Influence of the total saponin fraction from Dioscorea nipponica Makino on TLR2/4-IL1R receptor singnal pathway in rats of gouty arthritis

Ethnopharmacological relevanceDioscorea nipponica Makino have been extensively used in traditional medicine for the treatment of arthritic diseases, particularly gouty arthritis (GA). Materials and methodsSixty male Wistar rats were divided into six groups: the normal group, model group, colchicine group (COL) and three total saponin groups (RDN) (high dose [160mg/kg], middle dose [80mg/kg] and low dose [40mg/kg]). The mRNA and protein expression levels of TLR2, TLR4, IRAK1, TRAF6, TAK1, IKKα, IκBα and NF-κB in the synovial tissue of joint were detected by realtime PCR and WB methods respectively. The contents of IL-1β, IL-6 and TNF-α in the blood serum were measured by Elisa method. The activation of NF-κB was measured by EMSA method. ResultsOur study showed that RDN decreased both the mRNA and protein expressions of TLR2, TLR4, IRAK1, TRAF6, TAK1, IKKα, IκBα and NF-κB of the synovial tissue of joint of rats induced with monosodium urate crystal (MSU). They could also reduce the levels of IL-1β, IL-6 and TNF-α in the blood serum. Further, EMSA results showed that RDN reduced the DNA binding ability of NF-κB p65 of model group. ConclusionRDN has the effect of anti-inflammation in MSU-induced GA model. This is realised by influencing an important inflammatory signal pathway which is called TLR2/4-IL1R receptor signal pathway. It highlights the potential utility of RDN for the management of GA.

Therapeutic Effects of Chinese Medicine Herb Pair, Huzhang and Guizhi, on Monosodium Urate Crystal-Induced Gouty Arthritis in Rats Revealed by Anti-Inflammatory Assessments and NMR-Based Metabonomics.

The present study was undertaken to evaluate the therapeutic effects of Huzhang-Guizhi herb pair (HG), firstly included in Hu-Zhang Power documented in Taiping Shenghui Fang, on monosodium urate (MSU) crystals-induced gouty arthritis in rats. We found that pretreatment with HG in rats with gouty arthritis could significantly attenuate the ankle joint swelling, and this beneficial antigout effect might be mediated, at least in part, by inhibiting tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) production in synovial fluid as well as nuclear transcription factor-κB p65 (NF-κB p65) protein expression in synovial tissue. Moreover, metabonomic analysis demonstrated that 5 and 6 potential biomarkers associated with gouty arthritis in plasma and urine, respectively, which were mainly involved in energy metabolism, amino acid metabolism, and gut microbe metabolism, were identified. HG could reverse the pathological process of MSU-induced gouty arthritis through regulating the disturbed metabolic pathways. These results provided important mechanistic insights into the protective effects of HG against MSU-induced gouty arthritis in rats.

Lemnalol attenuates mast cell activation and osteoclast activity in a gouty arthritis model.

In this study, we investigated the effects of a soft coral-derived anti-inflammatory compound, lemnalol, on mast cell (MC) function and osteoclast activity in rats with monosodium urate (MSU) crystal-induced gouty arthritis. In this study, we examined the therapeutic effects of lemnalol on intra-articular injection of MSU induces gouty arthritis with the measurement of ankle oedema. Toluidine blue staining were used to analyse the infiltration and the percentage degranulation MCs. Immunohistochemical analysis showed CD117, transforming growth factor beta 1 (TGF-β1), matrix metalloproteinase 9 (MMP-9), the osteoclast markers cathepsin K and tartrate-resistant acid phosphatase (TRAP) protein expression in ankle tissue. We found that both infiltration and degranulation of MCs increased at 24 h after MSU injection in the ankle joint. Immunohistochemical analysis showed that MSU induced upregulation of TGF-β1, MMP-9, the osteoclast markers cathepsin K and TRAP in ankle tissues. Administration of lemnalol ameliorated MSU-induced TGF-β1, MMP-9, cathepsin K and TRAP protein expression. Taken together, our results show that MSU-induced gouty arthritis is accompanied by osteoclast-related protein upregulation and that lemnalol treatment may be beneficial for the attenuation of MC infiltration and degranulation and for suppressing osteoclast activation in gouty arthritis.