The preventive effect of Chinese sumac fruit against monosodium urate-induced gouty arthritis in rats by regulating several inflammatory pathways.

Chinese sumac (Rhus chinensis Mill.) fruit is a traditional Chinese medicinal material that can be consumed daily. This study aimed to investigate whether the ethanol extract of sumac fruits can ameliorate monosodium urate-induced gouty arthritis in rats from the perspective of inflammation. Results showed that the extract of Chinese sumac fruits can obviously prevent monosodium urate-induced gouty arthritis in rats. Further analyses revealed that this bioactivity may be mainly achieved by modulating several inflammatory pathways, including NLRP3, NF-κB, and MAPK pathways. In addition, the extract can also improve oxidative stress by reducing the levels of malondialdehyde and myeloperoxidase, increasing the contents of superoxide dismutase and glutathione. In conclusion, this study revealed that the Chinese sumac fruit can alleviate the pathological symptoms of gouty arthritis by inhibiting inflammatory responses and oxidative stress, which can provide a theoretical basis for the use of Chinese sumac fruits as a Chinese herbal medicine and health food for the prevention and treatment of gouty arthritis.

Effects and underlying mechanisms of food polyphenols in treating gouty arthritis: A review on nutritional intake and joint health.

Gouty arthritis, one of the most severe and common forms of arthritis, is characterized by monosodium urate crystal deposition in joints and surrounding tissues. Epidemiological evidence indicates that gouty arthritis incidence is sharply rising globally. Polyphenols are found in many foods and are secondary metabolites in plant foods. The anti-inflammatory and antioxidant effects of food polyphenols have been extensively studied in many inflammatory chronic diseases. Research has suggested that many food polyphenols have excellent anti-gouty arthritis effects. The mechanisms mainly include (a) inhibiting xanthine oxidase activity; (b) reducing the levels of inflammatory cytokines and chemokines; (c) inhibiting the activation of signaling pathways and the NLRP3 inflammasome; and (d) reducing oxidative stress. This paper reviews the research progress and pathogenesis of gouty arthritis and introduces the mechanisms of food polyphenols in treating gouty arthritis, which aims to explore the potential of functional foods in the treatment of gouty arthritis. PRACTICAL APPLICATIONS: The incidence rate of gouty arthritis has increased sharply worldwide, which has seriously affected people's quality of life. According to the current research progress, food polyphenols alleviate gouty arthritis through anti-inflammatory and antioxidant effects. This paper reviews the research progress and molecular pathogenesis of gouty arthritis and introduces the mechanisms of food-derived polyphenols in the treatment of gouty arthritis, which is helpful to the prevention and treatment of gouty arthritis.

Influence of Pinealectomy and Long-term Melatonin Administration on Inflammation and Oxidative Stress in Experimental Gouty Arthritis.

Gout is an inflammatory arthritis characterized by the deposition of monosodium urate (MSU) crystals in the joints or soft tissue. MSU crystals are potent inflammation inducers. Melatonin (MLT) is a powerful endogenous anti-inflammatory agent and effective in reducing cellular damage. In the present study, possible underlying mechanisms associated with anti-inflammatory and antioxidative effects were investigated in rats with gouty arthritis and melatonin deprivation treated with MLT. Fifty-six rats were divided into seven groups: control, sham control, pinealectomy (PNX), MSU (on the 30th day, single-dose 20 mg/ml, intraperitoneal), MSU + MLT (10 mg/kg/day for 30 days, intraperitoneal), MSU + PINX and MSU + PINX + MLT. PNX procedure was performed on the first day of the study. As compared to the controls, the results showed that MSU administration caused significant increases in oxidative stress parameters (malondialdehyde and total oxidant status). Besides, significant decreases in antioxidant defense systems (glutathione, superoxide dismutase and total antioxidant status) were observed. A statistically significant increase was found in the mean histopathological damage score in the groups that received MSU injection. It was found that histopathological changes were significantly reduced in the MSU + MLT group given MLT. In our study, it was determined that many histopathological changes, as well as swelling and temperature increase in the joint, which are markers of inflammation, were significantly reduced with MLT supplementation. These results suggest that melatonin ameliorates MSU-induced gout in the rat through inhibition of oxidative stress and proinflammatory cytokine production.

Lychnophora pinaster's effects on inflammation and pain in acute gout.

ETHNOPHARMACOLOGICAL RELEVANCE: Ethanolic extract of aerial parts from Lychnophora pinaster Mart. are used in traditional Brazilian medicine for treating pain, rheumatism and inflammation. AIM OF THE STUDY: Drugs for the treatment of gout present severe adverse effects, justifying the need to search for new therapeutic options. The aim of the present study was to evaluate the effects of the ethanolic extract of L. pinaster and its main constituents in arthritis induced in mice by the injection of monosodium urate (MSU) crystals. MATERIALS AND METHODS: Antinociceptive effect was investigated using an electronic pressure-meter nociception paw test in C57BL/6 mice. Anti-gouty arthritis was investigated in mice induced with gout by the injection of MSU crystals into their femur-tibial tissue. Ethanolic extract of the aerial parts of Lychnophora pinaster and its main chemical constituents were evaluated as treatment. RESULTS: The ethanolic extract and their main chemical constituents inhibited neutrophil migration, reduced IL-1ß and TNF-α concentrations in the inflamed tissue and showed antinociceptive activity. CONCLUSIONS: Gouty arthritis effects of the ethanolic extract can be attached to a synergistic effect of terpenes, flavonoids and phenolic acids present in the extract. Results obtained support the use of this extract and its main chemical constituents in the treatment of gout, inflammation, and pain.

Simiaosan alleviates the symptoms of gouty arthritis via the NALP3/IL­1ß pathway.

Previous studies have suggested that the herbal medicine simiaosan has beneficial effects on gouty arthritis (GA), for which conventional Western medicines are insufficient (particularly in cases of multiple episodes). The objective of the present study was to investigate the mechanism by which simiaosan alleviated the symptoms of GA. Sprague­Dawley rat models of acute GA were successfully established, as verified by pathological analyses. Additionally, an NLR family pyrin domain containing 3 (NLRP3) overexpression vector was constructed and a high transfection efficiency was confirmed by reverse transcription PCR. The following five treatment groups were established: i) Normal control; ii) model + saline; iii) model + simiaosan; iv) model + NALP3­overexpressing adenovirus + simiaosan; and v) model + empty vector adenovirus + simiaosan. The samples from mice in each group were subjected to hematoxylin and eosin (H&E) staining for assessing the histopathological changes, enzyme­linked immunosorbent assays for determining IL­1ß and TGF­ß1 levels and western blotting for evaluating NALP3 expression. H&E staining indicated that simiaosan could reduce the infiltration of inflammatory cells, while NALP3 overexpression aggravated the inflammatory response in tissues. Expression levels of IL­1ß, TGF­ß1 and NALP3 were significantly higher in the model and the model + NALP3­overexpressing adenovirus + simiaosan groups compared with the normal control group. Levels of IL­1ß, TGF­ß1 and NALP3 were significantly lower in the model + simiaosan and model + empty vector adenovirus + simiaosan groups compared with the model group. These results indicated that the effects of simiaosan were mediated through NALP3 inhibition. Therefore, the herbal medicine simiaosan was revealed to possess an ability to alleviate the symptoms of GA by regulating the NALP3/IL­1ß signaling pathway.

Baeckein E suppressed NLRP3 inflammasome activation through inhibiting both the priming and assembly procedure: Implications for gout therapy.

BACKGROUND: Baeckein E (BF-2) was isolated from the aerial parts of Baeckea frutescens L., which has a long history of use in traditional medicine in Southeast Asia to treat inflammatory disease. PURPOSE: BF-2 was identified to have inhibitory activity on nucleotide oligomerization domain (NOD)-like receptor protein-3 inflammasome (NLRP3) activation. This study aimed to investigate the related signaling cascade of BF-2 in both lipopolysaccharides (LPS)/ATP induced pyroptosis in J774A.1 macrophages and its application in a mouse model of gout induced by monosodium urate crystal (MSU). METHODS: The effect of BF-2 on NLRP3 inflammasome activation and gouty arthritis was studied in J774A.1 macrophages and male C57BL/6 mice. The J774A.1 macrophages were primed with LPS and stained by propidium iodide (PI) for cell pyroptosis detection. A gout mouse model was established by subcutaneous injection of MSU crystals into the hind paw of C57BL/6 mice. Mice were then randomly divided into different groups. The concentrations of IL-1ß and IL-18 in both J774A.1 macrophage and gout mouse model were analyzed by ELISA. The NLRP3 inflammasome related protein expression was detected by western blot analysis. The inhibitory effects of BF-2 on NLRP3 inflammasome assembly were analyzed by immunoprecipitation assay. The roles of BF-2 in mitochondrial damage were imaged by Mito Tracker Green and Mito Tracker Red probes. The inhibitory effects of BF-2 on ROS production were imaged by DCF (2',7'-dichlorofluorescein diacetate) probe. RESULTS: The results demonstrated BF-2 could significantly suppress the cell pyroptosis and IL-1ß secretion in macrophages. Furthermore, BF-2 significantly inhibited NLRP3 inflammasome activation and reduced ankle swelling in the gout mouse model. In detail, it alleviated mitochondrial damage mediated oxidative stress and inhibited the assembly of NLRP3 inflammasome by affecting the binding of pro-Caspase 1 and ASC. Moreover, BF-2 blocked NLRP3 activation by inhibiting the MAPK/NF-κB signaling pathways. CONCLUSIONS: Results demonstrated BF-2 inhibited NLRP3 inflammasome activation in both LPS primed macrophages and mouse model of gout through blocking MAPK/NF-κB signaling pathway and mitochondrial damage mediated oxidative stress. This study strongly suggests BF-2 could be a promising drug candidate against inflammatory diseases associated with NLRP3 inflammasome activation.

Icariin alleviates MSU-induced rat GA models through NF-κB/NALP3 pathway.

Icariin (ICA) has anti-inflammatory effects in some diseases, but its role in gouty arthritis (GA) is not clear. This study investigated the effects of ICA in monosodium urate (MSU)-induced GA rat models. GA rat models were induced by MSU, and co-treated with ICA of low-dose (20 mg/kg), medium-dose (40 mg/kg), and high-dose (80 mg/kg), respectively. The ankle swelling rates, haematoxylin-eosin (HE) staining changes, inflammatory factors (interleukin (IL)-1ß, IL-6, tumour necrosis factor-α (TNF-α)) and prostaglandin E2 (PGE2 ) levels in synovial tissues were detected. The antioxidants levels in rat serum, and NF-κB pathway-related proteins and NALP3 inflammasome expressions in synovial tissues were also analysed. In cell experiments, chondrocytes were co-treated with different concentrations of ICA (1, 5, 10 µmol/L) on the basis of MSU. The activities and inflammatory cytokines, hydroxyproline (Hyp) and glycosaminogly (GAG) expressions in chondrocytes were measured. In rat experiments, MUS increased the ankle swelling rates, promoted inflammatory cells infiltration, and increased IL-1ß, IL-6, TNF-α, PGE2 levels in synovial tissues, which were all alleviated by ICA. Moreover, ICA also suppressed nuclear translocation of NF-κB pathway-related proteins and reduced the expression of NALP3 inflammasome in rat models. As for cell experiments, ICA decreased the activity, inflammatory cytokines and GAG levels, and suppressed nuclear translocation of NF-κB pathway-related proteins of MSU-treated chondrocytes. In general, medium and high concentrations of ICA showed good effects. ICA has an inhibitory effect in MSU-induced rat GA models through NF-κB/NALP3 pathway, which may provide a direction for the treatment of GA. SIGNIFICANCE: Icariin (ICA) has anti-inflammatory effects in some diseases, but its role in gouty arthritis (GA) is not clear. This study excogitated that monosodium urate (MSU) increased the ankle swelling rates of rats, promoted inflammatory cells infiltration, and increased cytokines levels in synovial tissues, which were all alleviated by ICA. In related mechanism, we found that ICA might exert the catabatic functions through the NF-κB/NALP3 pathway. The findings of this study clarified that ICA may provide a direction for the treatment of patients with GA and illustrated the relevant underlying mechanism of its role.

Silencing of Gasdermin D by siRNA-Loaded PEI-Chol Lipopolymers Potently Relieves Acute Gouty Arthritis through Inhibiting Pyroptosis.

Gasdermin D (GSDMD) plays a causal role in NOD-like receptor protein 3 (NLRP3) inflammasome-mediated pyroptosis eruption, which has been regarded as a potential therapeutic target for pyroptosis-related diseases including acute gouty arthritis. In the present study, the synthesized PEI-Chol (cholesterol grafted polyethylenimine) was assembled with GSDMD small interfering RNA (siRNA) to form PEI-Chol/siGSDMD polyplexes, which provided high transfection efficiency for siRNA-mediated GSDMD knockdown. Then we evaluated the effect of GSDMD siRNA-loaded PEI-Chol on inflammatory cascades in bone-marrow-derived macrophages (BMDMs) and acute gouty arthritis animal models under MSU exposure. When accompanied by pyroptosis blockade and decreased release of interleukin-1 beta (IL-1ß), NLRP3 inflammasome activation was also suppressed by GSDMD knockdown in vivo and in vitro. Moreover, in MSU-induced acute gouty arthritis mice, blocking GSDMD with siRNA significantly improved ankle swelling and inflammatory infiltration observed in histopathological analysis. Furthermore, investigation using a mouse air pouch model verified the effect of siGSDMD-loaded PEI-Chol on pyroptosis of recruited macrophages and related signaling pathways in response to MSU. These novel findings exhibited that GSDMD knockdown relieved acute gouty arthritis through inhibiting pyroptosis, providing a possible therapeutic approach for MSU-induced acute gouty arthritis molecular therapy using PEI-Chol as a nucleic acid delivery carrier.

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-1ß, 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-1ß. In addition, TLR4, myeloid differentiation primary response gene 88 (MyD88), p-IKKß, 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.

The Extraction Solvent Influences the Anti-Inflammatory Effects of Jakyakgamcho-Tang in Lipopolysaccharide-Stimulated Macrophages and Mice with Gouty Arthritis.

Jakyakgamcho-Tang (JGT) is a traditional medicine used to treat muscular tension, spasm, and pain. Several studies have reported its clinical use as an anti-inflammatory and in gynaecological treatment. This study aimed to compare the anti-inflammatory effects of JGT according to extraction solvent, water (JGTW) and 30% EtOH (JGTE) on lipopolysaccharide (LPS)-stimulated macrophages and in mice with monosodium urate (MSU)-induced gouty arthritis. We evaluated the production of inflammatory mediators and cytokines and the expression of inducible nitric oxide (iNOS) and cyclooxygenase-2 (COX-2) in RAW 264.7 cells. We also examined oedema, pain, and inflammation in MSU-induced mice by measuring affected hind paw swelling, weight-bearing, pro-inflammatory cytokines levels, and myeloperoxidase (MPO) activity. In LPS-stimulated RAW264.7 cells, JGTW and JGTE significantly decreased prostaglandin (PG) E2(PGE2) production via suppressing COX-2 expression and cytokines interleukin-1ß and interleukin-6. Only JGTE reduced the production of NO and cytokines and the mRNA levels of iNOS and cytokines. In MSU-induced mice, JGTE and JGTW efficiently decreased paw swelling and attenuated joint pain. JGTE (200 and 300 mg/kg) effectively suppressed inflammation by downregulating pro-inflammatory cytokines (tumour necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-6) and MPO activity, which were only slightly reduced by JGTW. Our data demonstrate the anti-inflammatory activity of JGT in macrophage and gouty arthritis animal models and show that JGTE is more effective than JGTW at lower concentrations.

Anti-inflammatory and anti-gouty-arthritic effect of free Ginsenoside Rb1 and nano Ginsenoside Rb1 against MSU induced gouty arthritis in experimental animals.

Ginsenoside Rb1 (GsRb1) is the best constituent of ginseng and although it shows clinical efficacy as an antineoplastic, antioxidative and antirheumatic agent, its oral bioavailability is poor due to its limited solubility. In this study, the solubility of GsRb1 was improved by encapsulating it in polymeric nanocapsules (encapsulation efficiency: 99.79%), therefore, improving the oral bioavailability. The encapsulation resulted in stable, homogenous and well-dispersed nano-GsRb1, whose mean particle size and zeta potential were 183.9 nm and +36.9 mV, respectively. A significant improvement was observed in the in vitro release profile of nano-GsRb1 as compared to its free form. Our study also indicated a significant repression of the degradation of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα), the nuclear factor kappa B (NF-κB) signaling pathway, NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome activation, and the mitochondrial damage, thereby, reducing inflammation and gouty arthritis induced by monosodium urate (MSU), when compared to free GsRb1, strongly suggesting that polymeric nano-particles can be a novel approach for delivering the GsRb1 into the inflamed joints for a better treatment effectiveness.

Apamin from bee venom suppresses inflammation in a murine model of gouty arthritis.

ETHNOPHARMACOLOGICAL RELEVANCE: Bee venom (BV) has been used for the treatment of inflammatory diseases, such as rheumatoid arthritis, and for the relief of pain in traditional oriental medicine. AIM OF STUDY: The aim of this study was to determine the anti-inflammatory effect of BV on monosodium urate (MSU)-induced gouty arthritis in a mouse model. MATERIALS AND METHODS: To develop a mouse model of acute gouty arthritis, 4 mg 50 µL-1 of MSU crystal suspension was injected intradermally into the right paw. After MSU crystal injection, we evaluated inflammatory cytokine production in mice of the BV-treated (0.5 and 1 mg kg-1 body weight) and apamin (APM)-treated (0.5 and 1 mg kg-1 body weight) groups. The positive control group was administered a colchicine (1 mg kg-1 body weight) injection with MSU crystals. RESULTS: BV and APM treatment suppressed inflammatory paw edema in MSU-administered mice. It also exerted anti-inflammatory effects in mice with gouty arthritis by inhibiting proinflammatory cytokine production and inflammasome formation. Interestingly, MSU crystal formation was decreased by BV and APM treatment. CONCLUSIONS: These results suggest that the APM from BV might be useful for the treatment of gouty arthritis due to its anti-inflammatory activities.

Investigation of the mechanism of action of Porana sinensis Hemsl. against gout arthritis using network pharmacology and experimental validation.

ETHNOPHARMACOLOGICAL RELEVANCE: Porana sinensis Hemsl. has been widely used to treat joint pain and rheumatoid arthritis in traditional Chinese medicine (TCM). Although evidence exists to support a pharmacological action of P. sinensis for the treatment of gout arthritis (GA), the underlying mechanism of action remains unknown due to it being a multi-component and multi-target agent. AIM OF THE STUDY: To clarify the active compounds and mechanism of P. sinensis against GA. MATERIALS AND METHODS: The present study combined network pharmacology with experiments to clarify the mechanism of P. sinensis against GA. A protein-protein interaction network for gout was constructed to identify the potential drug targets, and molecular docking was subsequently performed to determine whether the protein was a target for the compounds of P. sinensis. KEGG pathway analysis was then conducted to elucidate the pathway involved in the P. sinensis-mediated treatment of gout. A rat model of GA was used to further investigate the mechanism of P. sinensis against GA. RESULTS: The network pharmacology study indicates that coumarins and chlorogenic acids of P. sinensis may serve as additives to GA treatment. P. sinensis played a role in the treatment of GA by regulating the PI3K-Akt, MAPK, NF-kappa B and toll-like receptor pathways and so on. Moreover, experimental validation suggests that P. sinensis extract significantly suppressed the expression of TLR2 and MyD88 mRNA, regulating the release of cytokines (IL-1ß, IL-4 and TGF-ß), lowering lipid peroxidation (MDA) and increasing antioxidant status (SOD). CONCLUSION: The present study clarifies the mechanism of P. sinensis against GA, and provides evidence to support its clinical use.

Anti­gouty arthritis and anti­hyperuricemia properties of celery seed extracts in rodent models.

Gout is a type of serious arthritis that is caused by hyperuricemia. Celery is an umbelliferous plant that was shown to exhibit anti­inflammatory activity in rodent. The present study aimed to investigate the effects and potential preliminary mechanisms of celery seed aqueous extract (CSAE) and celery seed oil extract (CSOL) for gout treatment. The components of CSAE and CSOL were systematically analyzed. In mice with hyperuricemia induced by potassium oxonate and yeast extract, CSAE and CSOL treatment reduced the serum levels of uric acid and xanthine oxidase. In addition, CSAE and CSOL reduced the levels of reactive oxygen species and increased the serum levels of superoxide dismutase and glutathione peroxidase in mouse serum. In rats with acute gouty arthritis induced by intra­articular injection of monosodium urate crystals, CSAE and CSOL treatment alleviated the swelling of the ankle joints and reduced inflammatory cell infiltration around the ankle joints. In addition, CSAE and CSOL reduced the levels of interleukin (IL)­1ß and tumor necrosis factor α and increased the levels of IL­10. The results of the present study suggested that celery seed extracts may have anti­gout properties, partially through anti­inflammatory and antioxidative effects.

Sirt1 ameliorates monosodium urate crystal-induced inflammation by altering macrophage polarization via the PI3K/Akt/STAT6 pathway.

OBJECTIVES: Acute gout is an inflammatory response to MSU crystals. In our previous research, Sirt1 was shown to have an effect in preventing acute gouty inflammation. In the current study, we aimed to investigate the underlying mechanism involving Sirt1 in acute gout. METHODS: The cytological changes and Sirt1 expression in the synovium were observed in patients with acute or intermittent gout. The effect of Sirt1 and its mechanism in gout were studied in macrophages, C57BL/6 mice and Sirt1+/- mice. RESULTS: Sirt1 expression was increased in the peripheral blood mononuclear cells (PBMCs) of patients with acute gout but not in the chronic tophus tissue. The arthritis score and numbers of inflammatory cells in injured paw tissue from murine gout models were upregulated in Sirt1+/- mice compared with wild-type mice. A PCR array of the paw tissue from murine gout models indicated that Sirt1 activation might attenuate MSU-induced inflammation by altering the polarization state of macrophages. Furthermore, in patients with acute gout, the phagocytosis of MSU crystals by a macrophage was found in a smear of the joint fluid and large amounts of macrophages were also found in the synovium. The activation of Sirt1 in gouty mice actually decreased the tendency toward M1 polarization. The inhibition of PI3K/Akt partially blocked the anti-inflammatory effect of Sirt1 and the translocation of STAT6, and phosphorylated STAT6 expression was decreased in RAW 264.7 cells treated with MSU crystals. CONCLUSION: Our studies revealed that Sirt1 ameliorates MSU-induced inflammation by altering macrophage polarization via the PI3K/Akt/STAT6 pathway.

15d-PGJ2-loaded nanocapsules ameliorate experimental gout arthritis by reducing pain and inflammation in a PPAR-gamma-sensitive manner in mice.

Gout arthritis (GA) is a painful inflammatory disease in response to monosodium urate (MSU) crystals in the joints. 15deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) is a natural activator of PPAR-γ with analgesic, anti-inflammatory, and pro-resolution properties. Thus, we aimed to evaluate the effect and mechanisms of action of 15d-PGJ2 nanocapsules (NC) in the model of GA in mice, since a reduction of 33-fold in the dose of 15d-PGJ2 has been reported. Mice were treated with 15d-PGJ2-loaded NC, inert NC, free 15d-PGJ2 (without NC), or 15d-PGJ2-loaded NC+ GW9662, a PPAR-γ inhibitor. We show that 15d-PGJ2-loaded NC provided analgesic effect in a dose that the free 15d-PGJ2 failed to inhibiting pain and inflammation. Hence, 15d-PGJ2-loaded NC reduced MSU-induced IL-1ß, TNF-α, IL-6, IL-17, and IL-33 release and oxidative stress. Also, 15d-PGJ2-loaded NC decreased the maturation of IL-1ß in LPS-primed BMDM triggered by MSU. Further, 15d-PGJ2-loaded NC decreased the expression of the components of the inflammasome Nlrp3, Asc, and Pro-caspase-1, as consequence of inhibiting NF-κB activation. All effects were PPAR-γ-sensitive. Therefore, we demonstrated that 15d-PGJ2-loaded NC present analgesic and anti-inflammatory properties in a PPAR-γ-dependent manner inhibiting IL-1ß release and NF-κB activation in GA. Concluding, 15d-PGJ2-loaded NC ameliorates MSU-induced GA in a PPAR-γ-sensitive manner.

Oridonin is a covalent NLRP3 inhibitor with strong anti-inflammasome activity.

Oridonin (Ori) is the major active ingredient of the traditional Chinese medicinal herb Rabdosia rubescens and has anti-inflammatory activity, but the target of Ori remains unknown. NLRP3 is a central component of NLRP3 inflammasome and has been involved in a wide variety of chronic inflammation-driven human diseases. Here, we show that Ori is a specific and covalent inhibitor for NLRP3 inflammasome. Ori forms a covalent bond with the cysteine 279 of NLRP3 in NACHT domain to block the interaction between NLRP3 and NEK7, thereby inhibiting NLRP3 inflammasome assembly and activation. Importantly, Ori has both preventive or therapeutic effects on mouse models of peritonitis, gouty arthritis and type 2 diabetes, via inhibition of NLRP3 activation. Our results thus identify NLRP3 as the direct target of Ori for mediating Ori's anti-inflammatory activity. Ori could serve as a lead for developing new therapeutics against NLRP3-driven diseases.

Achyranthis bidentatae radix enhanced articular distribution and anti-inflammatory effect of berberine in Sanmiao Wan using an acute gouty arthritis rat model.

ETHNOPHARMACOLOGICAL RELEVANCE: Sanmiao Wan (SMW) has been a basic prescription employed for the treatment for gout in the clinic since Yuan dynasty. Achyranthis bidentatae radix (ABR) is designed as a lower-guiding drug in SMW to augment the articular accumulation of active ingredients and improve the anti-inflammatory effect. AIM OF THE STUDY: Present study was undertaken to investigate the dose-response relationship of berberine in SMW between the articular concentration and anti-inflammatory effect in the knee joint under the lower-guiding of ABR. MATERIALS AND METHODS: Rats were divided into control group, model group and SMW without or with low, medium and high doses of ABR groups. Rat model of acute gouty arthritis (AGA) was established by intra-articular injection of 0.2 mL monosodium urate crystal (20 mg/mL) inside knee joint cavity on day 2 during drug treatment slots. Knee joint swelling, synovial hyperplasia and inflammatory cell infiltration were investigated for anti-inflammatory study. The concentrations of berberine in rat plasma and tissues were determined by UPLC-MS/MS method. The effect of ABR on the expression levels of P-glycoprotein (P-gp) and MDR1 mRNA in the synovial tissues of knee joints in AGA rats was examined by Western blot and RT-qPCR assay, respectively. RESULTS: The distribution of berberine increased by 6.53%, 44.31% and 212.96% in the knee joint and 474.93%, 631.01% and 1063.3% in the ankle for SMW with low, medium and high doses of ABR groups, compared with SMW without ABR group. Similarly, the plasma level of berberine increased by 19.81%, 143.4% and 681.13%. On the contrary, the distribution of berberine evidently decreased 3.23, 10.61 and 46.21-fold in heart and 3.68, 6.74 and 24.78-fold in lung. SMW with different doses of ABR groups exhibited better efficiency than SMW without ABR group on ameliorating knee joint swelling, inhibiting synovial hyperplasia and alleviating inflammatory cell infiltration of AGA rats. The treatment with ABR could down-regulate the MDR1 mRNA and P-gp expressions of synovial tissues of knee joints in AGA rats. CONCLUSIONS: The enhanced articular distribution of berberine in SMW was attributed to the lower-guiding effect of ABR, which could evidently increase the plasma concentration of berberine, improve the supply of blood of inflamed joint, reduce the distribution of berberine in heart and lung and significantly inhibit the MDR1 mRNA and P-gp expression of synovial tissues of knee joints in AGA rats. The dose-response relationship of berberine between the enhanced articular concentration and improved anti-inflammatory effect in the knee joint under the lower-guiding of ABR was observed for the first time.

Omega-3-carboxylic acids provide efficacious anti-inflammatory activity in models of crystal-mediated inflammation.

This study assesses the efficacy and exposure-response relationship of omega-3-carboxylic acids (OM-3 CA) in models of crystal-based inflammation. Human THP-1 macrophages and primary peripheral blood mononuclear cells exposed to multiple inflammatory crystal types were used to determine the anti-inflammatory potential of omega-3 (OM-3) fatty acids in vitro. Anti-inflammatory effects of OM-3 CA in vivo were tested in rat monosodium urate (MSU) crystal air pouch and rat knee intra-articular MSU injection models. Acute treatment with the OM-3 fatty acid docosahexaenoic acid suppressed MSU-, cholesterol crystal-, and calcium pyrophosphate crystal-mediated interleukin-1ß (IL-1ß) production in vitro. In vivo, OM-3 CA dose-dependently reduced crystal-mediated cell migration, exudate volume, and levels of IL-1ß and prostaglandin E2. Following intra-articular injection of MSU, treatment with OM-3-CA (1 mL/kg) and indomethacin (1 mg/kg) resulted in similar mean reductions in pain (23% and 41%, respectively) and swelling (58% and 50%, respectively), compared with controls. Additionally, in complex formulations of OM-3 fatty acids, high levels of palmitic acid could reduce the in vivo effect on crystal-mediated IL-1ß elevation. OM-3 CA has a broadly efficacious anti-inflammatory effect with a strong exposure-response relationship that could be beneficial in prevention and treatment of crystal arthritis, with potential applications in other IL-1ß-mediated diseases.

Kinsenoside screening with a microfluidic chip attenuates gouty arthritis through inactivating NF-κB signaling in macrophages and protecting endothelial cells.

Gouty arthritis is a rheumatic disease that is characterized by the deposition of monosodium urate (MSU) in synovial joints cause by the increased serum hyperuricemia. This study used a three-dimensional (3D) flowing microfluidic chip to screen the effective candidate against MSU-stimulated human umbilical vein endothelial cell (HUVEC) damage, and found kinsenoside (Kin) to be the leading active component of Anoectochilus roxburghi, one of the Chinese medicinal plant widely used in the treatment of gouty arthritis clinically. Cell viability and apoptosis of HUVECs were evaluated, indicating that direct Kin stimulation and conditioned medium (CM) from Kin-treated macrophages both negatively modulated with MSU crystals. Additionally, Kin was capable of attenuating MSU-induced activation of nuclear factor-κB/mitogen-activated protein kinase (NF-κB/MAPK) signaling, targeting IκB kinase-α (IKKα) and IKKß kinases of macrophages and influencing the expressions of NF-κB downstream cytokines and subsequent HUVEC bioactivity. Inflammasome NLR pyrin domain-containing 3 (NALP3) and toll-like receptor 2 (TLR2) were also inhibited after Kin treatment. Also, Kin downregulated CD14-mediated MSU crystals uptake in macrophages. In vivo study with MSU-injected ankle joints further revealed the significant suppression of inflammatory infiltration and endothelia impairment coupled with alleviation of ankle swelling and nociceptive response via Kin treatments. Taken together, these data implicated that Kin was the most effective candidate from Anoectochilus roxburghi to treat gouty arthritis clinically.