Joint nociceptor nerve activity and pain in an animal model of acute gout and its modulation by intra-articular hyaluronan

Suppression of TLR4/NF-κB signaling by kaurenoic acid in a mice model of monosodium urate crystals-induced acute gout

AIM

The aim of the current study was to investigate the potential therapeutic effect of kaurenoic acid (KA) against Monosodium Urate Crystals (MSU)-induced acute gout by downregulation of NF-κB signaling pathway, mitigating inflammation and oxidative stress. KA potentially targeted NF-κB pathway activation and provided comprehensive insights through multiple approaches. This was accomplished by advanced analytical techniques. This methodology highlighted the efficacy of KA in acute gout attacks offering new approach for gout management.

METHODS

In-vivo model of acute gout was established in BALB/c mice. Anti-inflammatory and urate-lowering potential was determined through pain behavioral evaluation, biochemical analysis, histological and immunohistochemical assays, radiological assessments, Fourier Transform Infrared (FTIR) analysis, and computational analysis.

RESULTS

The paw edema, joint thickness, and the frequency and duration of acute gout flare-ups were all significantly (p < 0.001) decreased by the administration of KA. A considerable reversal of inflammation and deterioration was observed in the KA-treated groups in X-ray examination. The FTIR spectroscopy indicated the changes in the molecular makeup of tissues, and modifications of biomolecules including proteins, lipids, and carbohydrates. Histopathological changes showed marked (p < 0.001) improvements in cellular structure of the paw, and inflammatory cell infiltration in the treatment groups. Trichrome staining revealed suppressed collagen deposition, inflammation, and tissue repair in the paw. In paw tissues, the KA therapy up-regulated IκB-α expression while down-regulating toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) expression. On the other hand, KA therapy greatly increased antioxidants and decreased oxidative stress indicators significantly (p < 0.001). According to Evans's blue permeability analysis, results showed that the treatment groups' vascular permeability was intensely reduced in comparison to the diseased group. Molecular docking studies indicated that KA appeared to have a high tendency to bind to protein targets. KA was associated with the drop in the cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β).

CONCLUSION

In conclusion, this study highlighted the potential therapeutic effect of KA in alleviating MSU-induced gout by suppressing the NF-κB signaling pathway. The anti-inflammatory and antioxidant activity was demonstrated by behavioral studies and advanced biochemical evaluations including blood analysis and oxido-nitrosative stress markers. Histopathological analysis, including H&E staining, immunohistochemistry, and Masson Trichrome staining, revealed tissue preservation, while FTIR and X-ray revealed structural improvements. Molecular docking verified strong binding affinity to NF-κB-related targets, verifying its mechanistic action. These findings suggest promising applications of KA in acute gout management due to its potent NF-κB modulating activity.

Mimicking the Human Articular Joint with In Vitro Model of Neurons-Synoviocytes Co-Culture

The development of in vitro models is essential in modern science due to the need for experiments using human material and the reduction in the number of laboratory animals. The complexity of the interactions that occur in living organisms requires improvements in the monolayer cultures. In the work presented here, neuroepithelial stem (NES) cells were differentiated into peripheral-like neurons (PLN) and the phenotype of the cells was confirmed at the genetic and protein levels. Then RNA-seq method was used to investigate how stimulation with pro-inflammatory factors such as LPS and IFNγ affects the expression of genes involved in the immune response in human fibroblast-like synoviocytes (HFLS). HFLS were then cultured on semi-permeable membrane inserts, and after 24 hours of pro-inflammatory stimulation, the levels of cytokines secretion into the medium were checked. Inserts with stimulated HFLS were introduced into the PLN culture, and by measuring secreted ATP, an increase in cell activity was found in the system. The method used mimics the condition that occurs in the joint during inflammation, as observed in the development of diseases such as rheumatoid arthritis (RA) or osteoarthritis (OA). In addition, the system used can be easily modified to simulate the interaction of peripheral neurons with other cell types.

Lipidomics Analysis Deepen Understanding the Molecular Mechanisms in a Gouty Model Induced by Combination of MSU Crystals Injection and High-Fat Diet Feeding and the Intervention Mechanisms of Allopurinol

Background

Gouty arthritis (GA) is a common inflammatory disease caused by deposition of monosodium urate (MSU) crystals in diarthrodial joints. GA attacks commonly involved in joint with red, swollen, heat and pain, and often happened in unilateral foot-first metatarsophalangeal. Accumulated studies have proved that lipids play critical roles in biological processes and lipids biomarkers can substitute for the diagnosis of various diseases.

Methods

Herein, shotgun lipidomics was used to quantitatively analyze serum lipidomes of a gouty model which was induced by injecting MSU crystals and feeding high-fat diet with/without treatment with allopurinol. Meanwhile, ELISA kit was used to detect mouse serum levels of inflammatory cytokines (eg, tumor necrosis factor-α, interleukin 1 beta) and HE staining was used to observe the infiltration of inflammatory cells in the foot pad.

Results

A total of 9 types of serum lipids were detected in lipidomics by shotguns, and the result of NMDS' analysis demonstrated significant differences in lipids profiles between the control and model group. It is worth noting that lipid abnormality in GA (such as Ceramide (Cer), sphingomyelin (SM), 4-hydroxyalkenals (HNE), phosphatidylinositol (PI), ethanolamine glycerophospholipid (PE), etc.) is related with phospholipid and energy metabolism, and allopurinol treatment could correct the aberrant metabolism of lipid to some extent.

Conclusion

Our results indicated that various aberrant lipid metabolisms were present in the established gouty model, and allopurinol treatment could relief this aberrant metabolism of lipids to some degree.

Gut microbiota mediated the therapeutic efficiency of Simiao decoction in the treatment of gout arthritis mice

BACKGROUND

Gut microbiota plays a significant role in the development and treatment of gouty arthritis. Simiao decoction has been shown to alleviate gouty arthritis by inhibiting inflammation, regulating NLRP3 inflammasome, and altering gut microbiota. However, there is no evidence to prove whether gut microbiota directly mediates the therapeutic efficiency of Simiao decoction in treating gout arthritis.

METHODS

In this study, fecal microbiota transplantation (FMT) was used to transfer the gut microbiota of gout arthritis mice treated with Simiao decoction or allopurinol to blank gout arthritis mice, in order to investigate whether FMT had therapeutic effects on gout arthritis.

RESULTS

Both Simiao decoction and allopurinol effectively reduced the levels of serum uric acid, liver XOD activity, foot thickness, serum IL-1β, and G-CSF in gout arthritis mice. However, Simiao decoction also had additional benefits, including raising the pain threshold, reducing serum TNF-α and IL-6, alleviating gut inflammation, and repairing intestinal pathology, which were not observed with allopurinol treatment. Moreover, Simiao decoction had a greater impact on gut microbiota than allopurinol, as it was able to restore the abundance of phylum Proteobacteria and genus Helicobacter. After transplantation into gout arthritis mice, gut microbiota altered by Simiao decoction exhibited similar therapeutic effects to those of Simiao decoction, but gut microbiota altered by allopurinol showed no therapeutic effect.

CONCLUSIONS

These findings demonstrates that Simiao decoction can alleviate gout arthritis symptoms by regulating gut microbiota.

RvD1 disrupts nociceptor neuron and macrophage activation, and neuroimmune communication reducing pain and inflammation in gouty arthritis in mice

BACKGROUND AND PURPOSE

Gouty arthritis is characterised by an intense inflammatory response to monosodium urate crystals (MSU), which induces severe pain. Current therapies are often ineffective in reducing gout-related pain. Resolvin D1 (RvD1) is a specialised pro-resolving lipid mediator with anti-inflammatory and analgesic proprieties. In this study, we evaluated the effects and mechanisms of action of RvD1 in an experimental mouse model of gouty arthritis, an aim that was not pursued previously in the literature.

EXPERIMENTAL APPROACH

Male mice were treated with RvD1 (intrathecally or intraperitoneally) before or after intraarticular stimulation with MSU. Mechanical hyperalgesia was assessed using an electronic von Frey aesthesiometer. Leukocyte recruitment was determined by knee joint wash cell counting and immunofluorescence. IL-1β production was measured by ELISA. Phosphorylated NF-kB and apoptosis-associated speck-like protein containing CARD (ASC) were detected by immunofluorescence, and mRNA expression was determined by RT-qPCR. CGRP release was determined by EIA and immunofluorescence. MSU crystal phagocytosis was evaluated by confocal microscopy.

KEY RESULTS

RvD1 inhibited MSU-induced mechanical hyperalgesia in a dose- and time-dependent manner by reducing leukocyte recruitment and IL-1β production in the knee joint. Intrathecal RvD1 reduced the activation of peptidergic neurons and macrophages as well as silenced nociceptor to macrophage communication and macrophage function. CGRP stimulated MSU phagocytosis and IL-1β production by macrophages. RvD1 downmodulated this phenomenon directly by acting on macrophages, and indirectly by inhibiting CGRP release and CGRP-dependent activation of macrophages.

CONCLUSIONS AND IMPLICATIONS

This study reveals a hitherto unknown neuro-immune axis in gouty arthritis that is targeted by RvD1.

Research on the effect and underlying molecular mechanism of Cangzhu in the treatment of gouty arthritis

OBJECTIVE

We aimed to identify the active ingredients and elucidate the underlying mechanism of action of Atractylodes lancea (Thunb.) DC (namely, Cangzhu) for the treatment of gouty arthritis (GA) based on network pharmacology methods. These findings are expected to provide a theoretical basis for the clinical treatment of GA.

METHODS

We used monosodium urate (MSU)-induced GA rats as a model to test the overall efficacy of Cangzhu in vivo. Then, the components of the Cangzhu decoction were analyzed and identified, and we screened the active ingredients and their targets. The GA disease targets were predicted by GeneCards and Disgenet databases and found to overlap in both databases. The STRING database was used to construct a protein-protein interaction network, followed by identification of the hub genes using Network Analyzer. Thereafter, Cytoscape software (version 3.8.2) was applied to construct a network for drug-active ingredient-key targets. Next, we applied cluego, a plug-in of Cytoscape, to perform gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) signal pathway enrichment analyses. Additionally, molecular docking was used to verify the characteristics of the key candidate components interacting with the hub therapeutic targets. Finally, we established an inflammatory injury model of LPS using RAW264.7 macrophages and used it to experimentally validate the critical active ingredients.

RESULTS

Cangzhu effectively protected against gouty arthritis in vivo, and network pharmacology results revealed various active ingredients in Cangzhu, such as wogonin, atractylenolide I and atractylenolide II. These compounds were found to act on 16 hub targets, including tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), interleukin-1β (IL-1β), prostaglandin-endoperoxide synthase 2 (PTGS2), recombinant mitogen-activated protein kinase 14 (MAPK14) and transcription factor p65 (RELA), which have significant effects on regulating inflammatory factors and apoptosis-related pathways to improve the proinflammatory or anti-inflammatory imbalance in the body, and this may be one of the underlying mechanisms of Cangzhu in anti-GA.

CONCLUSION

Our findings revealed that Cangzhu comprises multiple active components that exert various targeted effects during GA treatment. These findings provide relevant insights to illuminate the mechanism of Cangzhu in the treatment of GA and provide a reference for further experimental research.

Degenerative joint disease induced by repeated intra-articular injections of monosodium urate crystals in rats as investigated by translational imaging

The objective of this work was to assess the consequences of repeated intra-articular injection of monosodium urate (MSU) crystals with inflammasome priming by lipopolysaccharide (LPS) in order to simulate recurrent bouts of gout in rats. Translational imaging was applied to simultaneously detect and quantify injury in different areas of the knee joint. MSU/LPS induced joint swelling, synovial membrane thickening, fibrosis of the infrapatellar fat pad, tidemark breaching, and cartilage invasion by inflammatory cells. A higher sensitivity to mechanical stimulus was detected in paws of limbs receiving MSU/LPS compared to saline-injected limbs. In MSU/LPS-challenged joints, magnetic resonance imaging (MRI) revealed increased synovial fluid volume in the posterior region of the joint, alterations in the infrapatellar fat pad reflecting a progressive decrease of fat volume and fibrosis formation, and a significant increase in the relaxation time T2 in femoral cartilage, consistent with a reduction of proteoglycan content. MRI also showed cyst formation in the tibia, femur remodeling, and T2 reductions in extensor muscles consistent with fibrosis development. Repeated intra-articular MSU/LPS injections in the rat knee joint induced pathology in multiple tissues and may be a useful means to investigate the relationship between urate crystal deposition and the development of degenerative joint disease.

Selective inhibition of adenylyl cyclase subtype 1 reduces inflammatory pain in chicken of gouty arthritis

Lack of uricase leads to the high incidence of gout in humans and poultry, which is different from rodents. Therefore, chicken is considered to be one of the ideal animal models for the study of gout. Gout-related pain caused by the accumulation of urate in joints is one type of inflammatory pain, which causes damage to joint function. Our previous studies have demonstrated the crucial role of calcium-stimulated adenylyl cyclase subtype 1 (AC1) in inflammatory pain in rodents; however, there is no study in poultry. In the present study, we injected mono-sodium urate (MSU) into the left ankle joint of the chicken to establish a gouty arthritis model, and tested the effect of AC1 inhibitor NB001 on gouty arthritis in chickens. We found that MSU successfully induced spontaneous pain behaviors including sitting, standing on one leg, and limping after 1–3 h of injection into the left ankle of chickens. In addition, edema and mechanical pain hypersensitivity also occurred in the left ankle of chickens with gouty arthritis. After peroral administration of NB001 on chickens with gouty arthritis, both the spontaneous pain behaviors and the mechanical pain hypersensitivity were effectively relieved. The MSU-induced edema in the left ankle of chickens was not affected by NB001, suggesting a central effect of NB001. Our results provide a strong evidence that AC1 is involved in the regulation of inflammatory pain in poultry. A selective AC1 inhibitor NB001 produces an analgesic effect (not anti-inflammatory effect) on gouty pain and may be used for future treatment of gouty pain in both humans and poultry.

Minimally Invasive Embedding of Saturated MSU Induces Persistent Gouty Arthritis in Modified Rat Model

Introduction

Animal models are valid for in vivo research on the pathophysiological process and drug screening of gout arthritis. Intra-articular injection of monosodium urate (MSU) is the most common method, while stable MSU deposition enveloped by inflammatory cells was rarely reported.

Objective

To develop a modified gouty arthritis rat model characterized by intra-articular MSU deposition and continuous joint pain with a minimally invasive method.

Method

A total of twenty-four rats were randomly allocated into six groups. Three intervention groups of rats received intra-articular MSU embedment. Sham groups received pseudosurgeries with equal normal saline (NS). Gross parameters and pathological features of synovium harvested from anterior capsule were estimated. Mechanical pain threshold tests were conducted over a 96-hour period postoperatively. Moreover, quantitative immunofluorescence was conducted to assess tissue inflammation.

Result

After MSU embedding, rats got more persistent arthritic symptoms as well as tissue MSU deposition. More significant synovial swelling was detected in the MSU group compared to sham groups (P < 0.025). Behavioral tests showed that the embedding of MSU resulted in prolonged mechanical hyperalgesia during 2 hours to 96 hours postoperatively (P < 0.05). MSU depositions enveloped by inflammatory cells that express IL-1β and TNF-α were detected in embedding groups. Quantitative immunofluorescence suggested that the frequencies of MSU interventions upregulated expression of proinflammatory factors including IL-1β and TNF-α (P < 0.05).

Conclusion

A minimally invasive method was developed to establish modified rat model of intra-articular MSU deposition. This model was proved to be a simple reproducible method to mimic the pathological characteristics of persistent gouty arthritis.

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.

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.

Quantification of uric acid in vasculature of patients with gout using dual-energy computed tomography

BACKGROUND

Gout, caused by hyperuricemia and subsequent deposition of aggregated monosodium urate crystals (MSU) in the joints or extra-articular regions, is the most common inflammatory arthritis. There is increasing evidence that gout is an independent risk factor for hypertension, cardiovascular disease progression and mortality.

AIM

To evaluate if dual energy computed tomography (DECT) could identify MSU within vessel walls of gout patients, and if MSU deposits within the vasculature differed between patients with gout and controls. This study may help elucidate why individuals with gout have increased risk for cardiovascular disease.

METHODS

31 gout patients and 18 controls underwent DECT scans of the chest and abdomen. A material decomposition algorithm was used to distinguish regions of MSU (coded green), and calcifications (coded purple) from soft tissue (uncoded). Volume of green regions was calculated using a semi-automated volume assessment program. Between-group differences were analyzed using Mann-Whitney U exact test and nonparametric rank regression.

RESULTS

Gout patients had significantly higher volume of MSU within the aorta compared to controls [Median (Min-Max) of 43.9 (0-1113.5) vs 2.9 (0-219.4), P = 0.01]. Number of deposits was higher in gout patients compared to controls [Median (Min-Max) of 20 (0-739) vs 1.5 (0-104), P = 0.008]. However, the difference was insignificant after adjustment for age, gender, history of cardiovascular disease and diabetes. Increased age was positively associated with total urate volume (r_s = 0.64; 95% confidence interval: 0.43-0.78).

CONCLUSION

This pilot study showed that DECT can quantify vascular urate deposits with variation across groups, with gout patients possibly having higher deposition. This relationship disappeared when adjusted for age, and there was a positive relationship between age and MSU deposition. While this study does not prove that green coded regions are truly MSU deposition, it corroborates recent studies that show the presence of vascular deposition.

Simiao Decoction Alleviates Gouty Arthritis by Modulating Proinflammatory Cytokines and the Gut Ecosystem

Simiao decoction, a classical traditional Chinese medicine (TCM) formula, has been widely used for thousands of years due to its safety and efficiency in treating gouty arthritis. Utilizing serum proinflammatory cytokines and gut ecosystems, this study elucidated the mechanisms of alleviating gouty arthritis by Simiao decoction. Simiao decoction (4.0, 8.0, and 16.0 g/kg) was orally administered to gouty arthritis mice and febuxostat was given as a positive control. The spleen, kidney, and liver indexes indicated that Simiao decoction was safe for the treatment of gouty arthritis in C57BL/6 mice. Besides, our study demonstrated that Simiao decoction was effective for reducing the level of serum uric acid and decreasing MPO, XOD, and ADA activity, as well as alleviating gouty-related symptoms, such as foot swelling and pain. Moreover, Simiao decoction could also reduce some specific serum proinflammatory cytokines including IL-1β, IL-9, IFN-γ, MIP-1α and MIP-1β. We then surveyed the effects of Simiao decoction on the gut ecosystems in a systematic manner by combining network pharmacology, ELISA, western blot, and illumina sequencing. In the murine of model of gouty arthritis, Simiao decoction could suppress NLRP3 inflammasomes expression, reduce gut apoptosis through modulating TNF-α, Caspase 8, and AIFM1 protein expressions, affect lipid metabolism by regulating APOB, LPL, PPARα protein expressions and restore gut microbiota via reducing potential pathogens. Overall, these findings suggested that Simiao decoction was an effective therapeutic drug for gouty arthritis and the gut ecosystem might act as a potential anti-inflammatory target of Simiao decoction.

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.

N-Butyrylated hyaluronic acid ameliorates gout and hyperuricemia in animal models

Context: Hyaluronic acid (HA) plays critical roles in the structural skeleton, joint lubrication, renal function and cell signaling. We previously showed that partially N-butyrylated, low molecular weight, hyaluronic acid (BHA) exhibited an anti-inflammatory effect in cultured human macrophage, where inflammation was induced either by a TL-4 agonist or the low molecular weight HA itself, in dose-dependent fashion. Objectives: To investigate the anti-inflammatory, antioxidative, and antihyperuricemic effects of BHA using animal models of acute gouty arthritis and hyperuricemia. Materials and methods: The anti-inflammatory effect of articular BHA (10 and 50 μg) injections was evaluated by measuring joint swelling and the serum levels of inflammatory cytokines in a model of acute gouty arthritis induced by intra-articular injection of monosodium urate crystals in Wistar rats (n = 10/group), in comparison to the control group with saline injection. Antioxidative and antihyperuricemic activities were investigated using intraperitoneal injections of oteracil potassium and yeast extract hyperuricemic Balb/C mice, which were treated with intraperitoneal injection of BHA at day 6-8 in the model. Results: In the gouty arthritis rat model, BHA at a higher dosage (50 μg) demonstrated a strong anti-inflammatory effect by reducing the degree of articular swelling and the serum levels of IL-1β, IL-8, IFN-γ, and MCP-1 by 5.56%, 6.55%, 15.58% and 33.18%. In the hyperuricemic mouse model, lower dosage BHA (10 μg) was sufficient to provide antioxidative activities by significantly decreasing the ROS levels in both serum and liver by 14.87% and 8.04%, while improving liver SOD by 12.77%. Intraperitoneal injection of BHA suppressed uric acid production through reducing liver XO activity by 19.78% and decreased the serum uric acid level in hyperuricemic mice by 30.41%. Conclusions: This study demonstrated for the first time that BHA exhibits anti-inflammatory, antioxidative and antihyperuricemic effects in vivo, suggesting a potential therapeutic application of BHA in gouty arthritis and hyperuricemia.

Antinociceptive Effect of Single Components Isolated from Agrimonia pilosa Ledeb. Extract

Agrimonia pilosa Ledeb. produces an antinociceptive effect in ICR mice in both chemically induced and thermal pain models. In the present study, we examined the antinociceptive effects of single components isolated from Agrimonia pilosa Ledeb. (AP) extract in ICR mice. Three active compounds isolated from AP, including rutin, luteolin-7-O-glucuronide, and apigenin-7-O-glucuronide, were isolated and identified by comparing EI-MS, 1H-, 13C-NMR, and UV. We studied the antinociceptive effects of three single components administered orally at doses of 10 and 20 mg/kg in monosodium urate (MSU)-treated pain model as measured by von Frey test. Among these compounds, apigenin-7-O-glucuronide was more effective in the production of antinociceptive effects. We further characterized the antinociceptive effects and possible mechanisms of apigenin-7-O-glucuronide in writhing and formalin tests. Oral administration of Apigenin-7-O-glucuronide caused a reduction in the number of writhing and effectively reduced the pain behavior observed during the second phase of the formalin test in a dose-dependent manner. In addition, the pretreatment of yohimbine instead of naloxone or methysergide attenuated apigenin-7-O-glucuronide-induced antinociception in the writhing test. Moreover, apigenin-7-O-glucuronide caused reduction in the expression of p-P38, p-CREB, and p-mTOR induced by formalin injection. Our results indicate that apigenin-7-O-glucuronide shows an antinociceptive effect in various pain models. In addition, spinal α2-adrenergic receptors appear to be involved in the production of antinociception induced by apigenin-7-O-glucuronide. Furthermore, the antinociceptive effect of apigenin-7-O-glucuronide appears to be mediated by reduction in the expression of p-P38, p-CREB and p-mTOR levels in the spinal cord.