Carrageenan-induced Arthritis Research Articles

The effects of the cholinergic system on carrageenan-induced arthritis

The cholinergic system has been found to make an anti-inflammatory effect through the cholinergic anti-inflammatory pathway (CAIP), which suppresses the production of pro-inflammatory cytokines by secreting acetylcholine, a major neurotransmitter. However, no studies have been conducted on the effects of CAIP on joint pain and inflammation. In this study, we investigated the effects of muscarinic acetylcholine receptors (mAChRs) in knee arthritis. To examine pain behavioral changes, atropine (or saline for sham control) was pretreated in the joint cavity of rats at 1 % carrageenan + 5, 10, and 30 μL and the dynamic weight-bearing evaluation was performed. Synovial membranes were collected and cyclooxygenase-2 (COX-2) and interleukin-1β (IL-1β) were measured using a western blot. Hematoxylin and eosin staining was performed. Compared to that of the sham group, the weight-bearing of the affected knee joint significantly increased in the 1 % carrageenan + 10 μL atropine group (p < 0.05). However, no significant changes were observed in the 1 % carrageenan + 5 and 30 μL atropine groups. COX-2 and IL-1β and the number of inflammatory cells in synovial membrane significantly increased with 1 % carrageenan + 10 μL of atropine (p < 0.05). These results suggest that cholinergic system is involved in knee joint pain and inflammation and that mAChRs are potential therapeutic targets for knee joint arthritis.

Low-intensity pulsed ultrasound phonophoresis with diclofenac alleviated inflammation and pain via downregulation of M1 macrophages in rats with carrageenan-induced knee joint arthritis

ObjectiveThis study aimed to investigate the effects of low-intensity pulsed ultrasound (LIPUS) phonophoresis with diclofenac on inflammation and pain in the acute phase of carrageenan-induced arthritis in rats. Design60 male Wistar rats were randomly divided into the arthritis, diclofenac, LIPUS, phonophoresis, and sham-arthritis control groups. LIPUS and transdermal diclofenac gel were applied to the lateral side of the inflamed knee for 7 days, initiated postinjection day 1. In the phonophoresis group, diclofenac gel was rubbed onto the skin, followed by LIPUS application over the medication. Knee joint transverse diameters, pressure pain thresholds (PPTs), and paw withdrawal thresholds (PWT) were evaluated. The number of CD68-, CD11c-, and CD206-positive cells, and IL-1β and COX-2 mRNA expression were analyzed 8 days after injection. ResultsIn the phonophoresis group, the transverse diameter, PPT, PWT significantly recovered at the day 8 compared to those in the LIPUS and diclofenac groups. The number of CD68- and CD11c-positive cells in the phonophoresis group was significantly lower than that in the LIPUS and diclofenac groups, but no significant differences were observed among three groups in CD206-positive cells. IL-1β and COX-2 mRNA levels were lower in the phonophoresis group than in the arthritis group, although there were no differences among the LIPUS, diclofenac, and phonophoresis groups. ConclusionLIPUS phonophoresis with diclofenac is more effective to ameliorate inflammation and pain compared to diclofenac or LIPUS alone, and the mechanism involves the decrease of M1 macrophages.

Inhibitory effect of low‑intensity pulsed ultrasound on the fibrosis of the infrapatellar fat pad through the regulation of HIF‑1α in a carrageenan‑induced knee osteoarthritis rat model.

Fibrotic changes in the infrapatellar fat pad (IFP) are involved in the pathogenesis of knee osteoarthritis (KOA). HIF-1α is a transcription factor that is activated during hypoxia and is suggested to play a role in fibrosis in various organs. However, its participation in the fibrotic changes in IFP remains unclear. Therefore, we investigated the role of HIF-1α in IFP fibrosis using a carrageenan-induced KOA rat model and evaluated the potential of low-intensity pulsed ultrasound (LIPUS) as a novel treatment for KOA. A rat model was prepared by intra-articular injection of 0.5% carrageenan (50 µl) using 8-week-old male Wistar rats. Fibrosis of the IFP was evaluated histologically by hematoxylin and eosin and Sirius Red staining at 1 and 2 weeks after intra-articular injection. The mRNA expression levels of HIF-1α and fibrosis-related molecules, CTGF and VEGF, were analyzed using reverse transcription-quantitative PCR, and the DNA binding activity of HIF-1α was assessed using a binding assay. In addition, the effect of irradiation with LIPUS on the fibrosis of IFP was verified. Histological studies demonstrated a significant increase in the fibrosis of IFP 1 and 2 weeks after intra-articular injection of carrageenan, accompanied by overexpression of CTGF and VEGF, which was followed by upregulation of transcriptional activation of HIF-1α. Moreover, intervention with LIPUS for 2 weeks after injection of carrageenan attenuated fibrosis of IFP, accompanied by a significant reduction in the transcriptional activation of HIF-1α and decreased the gene expression levels of HIF-1α, CTGF, and VEGF. The present study demonstrated that activation of HIF-1α promoted fibrosis of IFP in carrageenan-induced arthritis in rats and that intervention with LIPUS decreased the activity of HIF-1α and inhibited fibrosis. These results suggest that LIPUS may serve as a novel approach for the treatment of KOA, through its modulation of HIF-1α.

Morphological changes in the tissues of the knee joints of rats in carrageenan-induced experimental arthritis

Every fifth inhabitant of the earth has been diagnosed with osteoarthritis of various etiologies. Morphological studies of arthritis provide a theoretical basis for creating optimal treatments for this pathology. Given the polyetiological nature of the disease, the choice of the optimal experimental model, which would be as close as possible to the real conditions of inflammatory process reproduction, is the topical issue. The purpose of the study was to confirm the pathological reaction of the joint tissues of laboratory animals in response to intraperitoneal administration of ƛ-carrageenan. The study was performed on 50 white Wistar rats males aged 12 weeks, weighing 130-150 g. The animals were euthanized by an overdose of anaesthesia according to the terms of the study (1 - 30 days). Fragments of the distal metaepiphyses of the femur and proximal metaepiphyses of the tibia were used for histological examination. Staining of sections obtained on the microtome was performed with haematoxylin, eosin, and Van Gieson`s stain. From the first day of the experimental study, a corresponding reaction of the joint tissues was being observed. Particularly pronounced were the changes in the synovial membrane in the form of oedema of the villi accompanied by an increased filling of blood vessels with foci of thrombosis. Gradually, up to 5 days in the synovial membrane, proliferative changes took place with a clear definition of the multilineage of the integumentary layer, vascular reaction with a tendency to thrombosis, in some places necrosis of synoviocytes was observed, but relative integrity of the morphological structure was still provided by protective barriers of bone and cartilage. On the 7th day pronounced resorption of both bone and cartilage tissue occurred, tissue structure became disorganized and functional layer became thin, accompanied by massive intracellular lysis. The process of synoviocytes necrobiosis with fatty degeneration spread. The histological picture of 10 days is characterized by generalized destruction of bone beams; the destroyed cartilage was replaced by granulation tissue with the presence of cavities. Massive foci of lymphocytic infiltration were observed in the synovial membrane. On the 14th day, a fragmentation of cartilage happened, most of the bone beams (trabeculae) were destroyed. After 3 weeks the morphological picture of cartilage tissue was determined by the appearance in the lacunae of viable cells, the number of which was close to normal. Bone beams were restored, although they remained thin. In a synovial membrane, the hyperplasia of apical departments of villi, leukocytes infiltration, disorganization of connective tissue, and separate vascular disturbances remained. 30 days of the experiment were characterized by a relative recovery of structural relationships to normal. The obtained data confirm the feasibility of using carrageenan in experimental studies of osteoarthritis.

Physicochemical and pharmacological investigations of polyvinylpyrrolidone - tetrahydroxyborate hydrogel containing the local anesthetic lidocaine

The short time of action and systemic toxicity of local anesthetics limit their clinical application. The objective of this work was to develop a modified release system for the local anesthetic lidocaine (LDC), using polyvinylpyrrolidone-Tetrahydroxyborate (PVP-THB) hydrogel to improve the pharmacological properties of the drug and their anesthetic activities investigated. The mechanical properties, rheological, swelling ratio, and water content behavior of candidate formulations were investigated. An increase in THB concentrations increased the storage modulus (G') and the loss modulus (G″) but decreased the loss tangent (tan δ < 1). In vitro release of PVP and THB were assessed to evaluate potential clinical dosing of free species originating from the hydrogel structure. The profiles of PVP-THB/LDC showed that the release of associated LDC was slower than that of the free drug. Evaluating the cytotoxic effect of these hydrogels on an in vitro mouse fibroblast (L929) cells showed their good cytotoxic activity towards L929 prolonged its anesthetic action. Particles were characterized using a scanning electron microscope (SEM) and atomic force microscopy (AFM) analyses confirming the amorphous nature and the uniformity of LDC inclusion in the PVP-THB hydrogel. The continuous release of LDC from the PVP-THB hydrogel was observed for more than three days, without a remarkable initial burst, which is probably owing to the stable entrapment of LDC in the PVP-THB core of the hydrogel. We evaluated the analgesic effect of PVP-THB/LDC in the carrageenan-induced arthritis rats model. Results showed that PVP-THB/LDC has a stronger and longer analgesic effect when administered in inflamed areas. This new formulation could potentially be used in future applications involving the gradual release of local anesthetics.

Influence of the potential dependent calcium channel blockers to the development of carrageenan-induced aseptic inflammation

Background: A number of patients with diseases of the cardiovascular system simultaneously take anti-inflammatory medicines due to the presence of concomitant chronic inflammatory diseases such as rheumatism, arthritis, and podagra. Considering the above, it seems important to study the effect of calcium antagonists (CA) on the course of the inflammatory process. Aim and Objectives: The purpose of the study was an investigation of the effect of amlodipine, diltiazem, and cinnarizine in comparison with diclofenac sodium on the course of carrageenan-induced aseptic arthritis. Materials and Methods: The experiments were carried out on outbred white rats, males, and weigh 150–170 g. The inflammation was induced by the subplantary injection of a 1% aqueous solution of carrageenan in a volume of 0.1 ml. The studied medicines diclofenac sodium at a dose of 10 mg/kg, amlodipine and diltiazem at doses of 20 mg/kg, and cinnarizine at doses of 50 mg/kg were intragastrically administered to experimental animals 1 h before the injection of carrageenan. Measurement of the paw volume of animals was carried out using a plethysmometer Results: The anti-inflammatory activity of amlodipine in the indicated hours of observation was 34.1, 36.8, 37.8, and 39.7%, respectively. Сinnarizine also had a distinct anti-exudative effect, after 1, 2, 3, and 4 h of the experiment value of anti-inflammatory activity of it were as following: 38.6, 40.3, 41.9, and 44.0%, respectively. Conclusion: Blockers of potential-dependent calcium channels clearly suppress the exudative phase of aseptic inflammation. The studied medicines are arranged in a descending order by their pharmacological activity in the following row: diclofenac sodium = diltiazem> cinnarizine> amlodipine.

Histological Assessment of Anti-inflammatory Effectiveness of 940 Nanometer LLLT on Carrageenan Induced Arthritis in Temporomandibular Joint in Wistar Albino Rats

Low level laser therapy is very promising method to treat temporomandibular joint disorders, the aim of this study was to assess the effectiveness of different energy density of 940nm diode laser, 120 Westar albino male rats (250g weight, three months old) were used in this study, divided randomly into four experimental groups; negative control group injected with saline, positive control group injected with carrageenan solution with no treatment, study group injected with carrageenan and treated with 171J/cm2 LLLT group, and study group injected with carrageenan and treated with 74J/cm2 LLLT group, animals were euthanized in day;1, 3, and 7, histological slides obtained and examined under light microscope for assess acute and chronic inflammatory infiltrations. It was concluded that LLLT using 74J/cm2 energy density had a very efficient anti-inflammatory effect.

Clinical Assessment of Anti-inflammatory Activity of 940 Nanometer Low Level laser Therapy on Carrageenan Induced Arthritis in Temporomandibular Joint in Wistar Albino Rats

Clinical Assessment of Anti-inflammatory Activity of 940 Nanometer Low Level laser Therapy on Carrageenan Induced Arthritis in Temporomandibular Joint in Wistar Albino Rats

Influence of eugenol on oxidative stress biomarkers in the liver of carrageenan-induced arthritis rats

Background Eugenol is the foremost constituent of clove oil and widely distributed in many plants. It possesses many pharmaceutical applications, including antioxidant, anti-inflammatory, and anti-tumorigenic properties, among others. This study evaluates the influence of eugenol on oxidative stress biomarkers in the liver of carrageenan-induced arthritis (CIA) rats. Methods Sixty albino rats were randomly divided into 10 (n=6) groups. Group I is the control group that received saline solution orally. Groups II and VII rats received 2.5 mg/kg of eugenol orally (EUG-2.5). Rats in groups III/VIII and IV/IX received 5 and 10 mg/kg of eugenol orally (EUG-5 and EUG-10), respectively. Groups V and X received 0.2 mg/kg of dexamethasone (DEX-0.2) orally. Groups VI to X were injected with 1% carrageenan intra-articularly. Behavioral studies were conducted after 21 days of treatment. Thereafter, the animals were sacrificed, and the livers were isolated and used for biochemical analysis. Results Reduced body weight in arthritic rats was recorded compared to normal controls. Reduced tibiofemoral joint edema and increased spontaneous movement were observed in CIA rats with decreased superoxide dismutase, catalase, reduced glutathione (GSH), glutathione peroxidase, and GSH S-transferase activities compared with the normal control group. Increased endogenous enzyme activities and decreased elevated lipid peroxidation were also observed after eugenol treatment. Conclusion Eugenol ameliorates carrageenan-induced oxidative stress in the liver of arthritic rats.

Modulatory effect of eugenol on arginase, nucleotidase, and adenosine deaminase activities of platelets in a carrageenan-induced arthritis rat model: A possible anti-arthritic mechanism of eugenol

This study investigated the effect of eugenol on arginase, nucleotidase and adenosine deaminase activities in platelets of carrageenan-induced arthritic rat model to explain a possible anti-arthritic mechanism of eugenol. Fifty adult female rats (140–250 g) were divided into ten (10) groups (n = 5). Group I received oral administration of corn oil, group II received 2.50 mg/kg of eugenol, group III and IV rats received oral administration of 5.0 and 10.0 mg/kg of eugenol respectively, group V received 0.20 mg/kg of dexamethasone orally, group VI rats was injected with 1% carrageenan (arthritic rats) and received saline solution orally (arthritic control rat group), group VII, VIII and IX: arthritic rats received 2.50, 5.0 or 10 mg/kg of eugenol orally respectively, group X: arthritic rats was administered with 0.20 mg/kg of dexamethasone orally. The animals were treated for 21 days, thereafter, tibiofemoral histological examination, thiobabituric acid reactive substances level, arginase, nucleoside triphosphate diphosphohydrolase, 5´-nucleotidase and adenosine deaminase activities were assessed. Tibiofemoral histological examination result showed that infiltration of inflammatory cells was significantly decreased with an increase in eugenol dose. Activities of arginase, adenosine triphosphate and adenosine monophosphate hydrolyses were significantly decreased while adenosine diphosphate hydrolysis and adenosine deaminase activities were significantly increased in arthritic rat groups administered with different doses of eugenol. Therefore, eugenol might be a natural complement and alternative promising anti-arthritic agent. These possible anti-arthritic mechanisms may be partly through the modulation of arginase and adenosine nucleotides hydrolyzing enzyme activities as well as the antioxidative action of eugenol.

Development of a local anesthetic lidocaine-loaded redox-active injectable gel for postoperative pain management.

1. We have been working on nanomaterials, which effectively eliminate ROS, avoiding dysfunction of mitochondria in healthy cells. 2. We designed redox injectable gel using polyion complexed flower type micelle, which can eliminates ROS locally. 3. We could prepare local anesthesia-loaded redox injectable gel (lido@RIG). 4. Drug release could be extended by local administration of lido@RIG. 5. Deprotonation of lidocaine improved anesthetic effect because ROS were eliminated locally by RIG. 6. Local inflammation could be also suppressed by lido@RIG.

The effect of intra-articular vanilloid receptor agonists on pain behavior measures in a murine model of acute monoarthritis.

Arthritis is the most common cause of disability in the US, and the primary manifestation of arthritis is joint pain that leads to progressive physical limitation, disability, morbidity, and increased health care utilization. Capsaicin (CAP) is a vanilloid agonist that causes substance P depletion by interacting with vanilloid receptor transient receptor potential V1 on small unmyelinated C fibers. It has been used topically for analgesia in osteoarthritis with variable success. Resiniferatoxin (RTX) is an ultra potent CAP analog. The aim of this study was to measure the analgesic effects of intra-articular (IA) administration of CAP and RTX in experimental acute inflammatory arthritis in mice. Evoked pain score (EPS) and a dynamic weight bearing (DWB) device were used to measure nociceptive behaviors in a murine model of acute inflammatory monoarthritis. A total of 56 C57B16 male mice underwent EPS and DWB testing – 24 nonarthritic controls and 32 mice with carrageenan-induced arthritis. The effects of pretreatment with 0.1% CAP, 0.0003% RTX, or 0.001% RTX were measured. Nociception was reproducibly demonstrated by increased EPS and reduced DWB measures in the affected limb of arthritic mice. Pretreatment with 0.001% RTX resulted in statistically significant improvement in EPS and DWB measures when compared with those observed in carrageenan-induced arthritis animals. Pretreatment with IA 0.0003% RTX and IA 0.01% CAP resulted in improvement in some but not all of these measures. The remaining 24 mice underwent evaluation following treatment with 0.1% CAP, 0.0003% RTX, or 0.001% RTX, and the results obtained were similar to that of naïve, nonarthritic mice.

Dispositivo implantável de EUDRAGIR/PCL-T/ Diclofenaco de sódio: caracterização mecânica, liberação do fármaco e atividade anti-inflamatóriain vivo

Modelo do estudo: experimental. Objetivo do estudo: produzir, descrever e avaliar a atividade antiinflamatória de um sistema polimérico implantável contendo diclofenaco de sódio na inflamação aguda induzida por carragenina em um modelo de artrite emjoelho de ratos. Metodologia: Um dispositivo implantável de Eudragit RS 100 e PCL-T (EUDPCL-T) contendo 3.0 mg de diclofenaco de sódio foi produzido. Os dispositivos foram implantados na região peri-articular posterior dos joelhos de ratos induzidos a artrite. Resultados: Após 6 horas e no dia 7 após a indução de artrite, o edema do joelho foi avaliado, e os mediadores inflamatórios, mieloperoxidase (MPO) e óxido nítrico foram analisados. Os resultados foram comparados com a administração oral de 30 mg / kg de diclofenaco de sódio. Conclusões: O dispositivo implantável foi capaz de produzir os mesmos resultados anti-inflamatórios na artrite induzida por carragenina quando comparadoscom o tratamento por via oral, entretanto com doses mais baixas

The effects of Chamaecyparis obtusa essential oil on pain-related behavior and expression of pro-inflammatory cytokines in carrageenan-induced arthritis in rats.

Chamaecyparis obtusa essential oil (COE) has been widely used to treat allergic diseases and was suggested to exert anti-inflammatory, antioxidant, and antimicrobial effects. This study evaluated the effects of COE on pain-related behavior and pro-inflammatory cytokines in rats with carrageenan (CGN)-induced arthritis. Reduced dynamic weight load on inflamed joint in voluntarily walking rats was used as the behavior test for arthritic pain; 10% COE-treated group was significantly attenuated pain (6-8 h post-CGN injection) compared to VEH (mineral oil)-treated group. In addition, the protein levels of interleukin (IL)-1β, tumor necrosis factor-α, IL-6 (6-8 h), and cyclooxygenase (COX)-2 (8 h) within the synovial membrane, as well as IL-1β, COX-2 (6-8 h), and IL-6 (5-7 h) within the meniscus, of 10% COE-treated group were significantly reduced. The current results implicate that COE has anti-inflammatory and anti-nociceptive effects on arthritis in rats.

Analgesic, anti-inflammatory and anti-pyretic activities of D-3-O-methylchiroinositol isolated from stem bark of Piliostigma thonningii

D-3-O-methylchiroinositol isolated from the stem bark of Piliostigma thonningii was evaluated for analgesic, anti-inflammatory and anti-pyretic activities. The compound was screened for analgesic activity by the acetic acid-induced writhing and tail immersion tests. The anti-inflammatory activities were evaluated by the carrageenan-induced paw edema and Freund adjuvant-induced arthritis tests, while its anti-pyretic activity was determined using the yeast-induced pyrexia test. D-3-O-methylchiroinositol (10, 30 and 60 mg/kg) significantly (P < 0.01) reduced the number of acetic acid-induced writhing. In the tail immersion test, by 15, 45, 30 and 60 min post-treatment, tail withdrawal times in D-3-O-methylchiroinositol (30 and 60 mg/kg) were significantly (P < 0.01) longer compared to reaction times recorded in control group. The paw volumes obtained in the 60 mg/kg D-3-O-methylchiroinositol group by 1 h post-carrageenan injection were significantly (P < 0.05) lower than the paw volume of control rats. At 2 and 3 h, the paw volumes in the D-3-O-methylchiroinositol (10, 30 and 60 mg/kg) were significantly (P < 0.05) lower than paw volume of the control group. In the subacute phase of arthritis (18 h), paw volumes in D-3-O-methylchiroinositol (30 and 60 mg/kg) were significantly (P < 0.05 and P < 0.01, respectively) lower compared to paw volume in the control group. In the chronic phase (30 days) of arthritis, paw volumes in the D-3-O-methylchiroinositol (10, 30 and 60 mg/kg) were significantly (P < 0.01) lower than paw volume of the control group. The rectal temperatures of the 60 mg/kg D-3-O-methylchiroinositol were significantly lower at 1, 2, 3, 4 and 5 h post-yeast injection compared to those of the control. The findings of this study establish that D-3-O-methylchiroinositol has analgesic, anti-inflammatory and anti-pyretic activities.

PEP-1-FK506BP12 inhibits matrix metalloproteinase expression in human articular chondrocytes and in a mouse carrageenan-induced arthritis model.

The 12 kDa FK506-binding protein (FK506BP12), an immunosuppressor, modulates T cell activation via calcineurin inhibition. In this study, we investigated the ability of PEP-1-FK506BP12, consisting of FK506BP12 fused to the protein transduction domain PEP-1 peptide, to suppress catabolic responses in primary human chondrocytes and in a mouse carrageenan-induced paw arthritis model. Western blotting and immunofluorescence analysis showed that PEP-1-FK506BP12 efficiently penetrated chondrocytes and cartilage explants. In interleukin-1β (IL-1β)-treated chondrocytes, PEP-1-FK506BP12 significantly suppressed the expression of catabolic enzymes, including matrix metalloproteinases (MMPs)-1, -3, and -13 in addition to cyclooxygenase-2, at both the mRNA and protein levels, whereas FK506BP12 alone did not. In addition, PEP-1-FK506BP12 decreased IL-1β-induced phosphorylation of the mitogen-activated protein kinase (MAPK) complex (p38, JNK, and ERK) and the inhibitor kappa B alpha. In the mouse model of carrageenan-induced paw arthritis, PEP-1-FK506BP12 suppressed both carrageenan-induced MMP-13 production and paw inflammation. PEP-1-FK506BP12 may have therapeutic potential in the alleviation of OA progression. [BMB Reports 2015; 48(7): 407-412]

Enhanced Therapeutic Anti-Inflammatory Effect of Betamethasone on Topical Administration with Low-Frequency, Low-Intensity (20 kHz, 100 mW/cm2) Ultrasound Exposure on Carrageenan-Induced Arthritis in a Mouse Model

The purpose of this work was to investigate whether low-frequency, low-intensity (20 kHz, <100 mW/cm2, spatial-peak, temporal-peak intensity) ultrasound, delivered with a lightweight (<100 g), tether-free, fully wearable, battery-powered applicator, is capable of reducing inflammation in a mouse model of rheumatoid arthritis. The therapeutic, acute, anti-inflammatory effect was estimated from the relative swelling induced in mice hindlimb paws. In an independent, indirect approach, the inflammation was bio-imaged by measuring glycolytic activity with near-infrared labeled 2-deoxyglucose. The outcome of the experiments indicated that the combination of ultrasound exposure and topical application of 0.1% (w/w) betamethasone gel resulted in statistically significantly (p < 0.05) enhanced anti-inflammatory activity in comparison with drug or ultrasound treatment alone. The present study underscores the potential benefits of low-frequency, low-intensity ultrasound-assisted drug delivery. However, the proof of concept presented indicates the need for additional experiments to systematically evaluate and optimize the potential of, and the conditions for, tolerable low-frequency, low-intensity ultrasound-promoted non-invasive drug delivery.

A comparison of DigiGait&amp;trade; and TreadScan&amp;trade; imaging systems: assessment of pain using gait analysis in murine monoarthritis

PurposeCarrageenan-induced arthritis is a painful acute arthritis model that is simple to induce, with peak pain and inflammation occurring at about 3 hours. This arthritis model can be evaluated using semiquantitative evoked or non-evoked pain scoring systems. These measures are subjective and are often time- and labor-intensive. It would be beneficial to utilize quantitative, nonsubjective evaluations of pain with rapid assessment tools. We sought to compare the DigiGait™ and TreadScan™ systems and to validate the two gait analysis platforms for detection of carrageenan-induced monoarthritis pain and analgesic response through changes in gait behavior.MethodsNon-arthritic mice and carrageenan-induced arthritic mice with and without analgesia were examined. A painful arthritic knee was produced by injection of 3% carrageenan into the knee joint of adult mice. Analgesic-treated mice were injected subcutaneously with 0.015 mg/mL (0.5 mg/kg) buprenorphine. Five-second videos were captured on the DigiGait™ or TreadScan™ system and, after calculating gait parameters, were compared using student’s unpaired t-test.ResultsWe found the DigiGait™ system consistently measured significantly longer stride measures (swing time, stance time, and stride time) than did TreadScan™. Both systems’ measures of variability were equal. Reproducibility was inconsistent on both systems. While both systems detected alterations in some gait measures after carrageenan injection, none of the alterations were seen with both systems. Only the TreadScan™ detected normalization of gait measures after analgesia, but the system could not detect normalization across all measures that altered due to arthritis pain. Time spent on analysis was dependent on operator experience.ConclusionNeither the DigiGait™ nor TreadScan™ system was useful for measuring changes in pain behaviors or analgesic responses in acute inflammatory monoarthritic mice.

(E)-3-(3,4-Dimethoxyphenyl)-1-(5-hydroxy-2,2-dimethyl-2H-chromen-6-yl)prop-2-en-1-one ameliorates the collagen-arthritis via blocking ERK/JNK and NF-κB signaling pathway

Our previous report has shown a natural pyranochalcones-derived compound, (E)-3-(3,4-Dimethoxyphenyl)-1-(5-hydroxy-2,2-dimethyl-2H-chromen-6-yl)prop-2-en-1-one (5b), that exerted protection against carrageenan-induced hind paw edema and adjuvant-induced arthritis. In this study, collagen-induced arthritis (CIA) model was used to further examine the anti-arthritic effects of 5b in vivo; the underlying molecular mechanisms of action were also investigated using a murine monocytic cell line, RAW264.7 cells. Here we showed that oral administration of 5b (20mg/kg) significantly suppressed the progression of arthritis. Improvement in disease severity was accompanied by inhibition of CD68-positive cells in knee joint and reduced pro-inflammatory cytokines TNF-α, IL-1β and IL-6 in serum. In vitro, 5b suppressed expressions of iNOS, cyclooxygenase-2 (COX-2), TNF-α, IL-6 and IL-1β as well as productions of nitric oxide (NO) and prostaglandin E2 (PGE2) in lipopolysaccharide (LPS)-treated macrophages. This compound also significantly suppressed LPS-induced NF-κB activation, including phosphorylation of I-κB, degradation of I-κB, and nuclear translocation of p65 and p50. Treatment with 5b also blocked LPS-induced expression of TLR4 remarkably, suppressed degradation of IRAKs and phosphorylations of JNK and ERK, but had little effect to p38 kinase activation. These findings indicated that 5b might be a therapeutic agent for rheumatoid arthritis, and exerted an anti-inflammatory effect mainly through mediating TLR4, NF-κB and ERK/JNK signaling pathways in monocytes.

Phosphatidylserine inhibits inflammatory responses in interleukin-1β–stimulated fibroblast-like synoviocytes and alleviates carrageenan-induced arthritis in rat

Recently, phosphatidylserine (PS) has received attention for its anti-inflammatory effect; however, the molecular mechanisms of its action have not been fully understood. Thus, we hypothesized that PS might have antiarthritic and anti-inflammatory effects. To test this hypothesis, the in vitro anti-inflammatory effect of soybean-derived PS was tested on interleukin (IL)-1β–stimulated fibroblast-like synoviocytes from rheumatoid arthritis patients (RA-FLS) by measuring the levels of IL-6, IL-8, prostaglandin E2, and vascular endothelial growth factor by enzyme-linked immunosorbent assay. The analgesic and antiarthritic activities of PS were investigated in rat models of carrageenan-induced acute paw pain and arthritis. The former was evaluated with a paw pressure test; the latter, by measuring paw volume and weight distribution ratio. In addition, the participation of mitogen-activated protein kinase signaling in the anti-inflammatory and antiarthritic effects of PS was investigated in RA-FLS. Phosphatidylserine inhibited the production of inflammatory mediators IL-6; IL-8; vascular endothelial growth factor; and, in particular, prostaglandin E2 in IL-1β–stimulated RA-FLS. These effects were associated with abrogation of inhibitor of nuclear factor–κBα phosphorylation and suppression of p38 and c-jun amino terminal kinase but not extracellular signal–regulated kinase 1/2 phosphorylation. In rats, PS also showed a significant inhibitory effect on arthritic and nociceptive symptoms induced by carrageenan. These findings suggest that PS has anti-inflammatory and antiarthritic effects in vitro and in in vivo animal models; thus, PS should be further studied to determine its potential use as either a pharmaceutical or dietary supplement for alleviating arthritic symptoms.