Predictivity and sensitivity of animal models of arthritis

Therapeutic potential of phytocompounds in rheumatoid arthritis: Molecular insights and clinical applications

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by systemic involvement, inflammation, and the destruction of synovial joints. RA can be categorized as anti-citrullinated protein antibodies-positive or negative based on genetic risk factors and autoantibodies. This review systematically sourced articles related to RA, phytocompounds, signaling pathways, and clinical insights from primary medical databases, including Scopus, PubMed, and Web of Science. This review explores the therapeutic potential of phytocompounds in treating RA by targeting key inflammation and immunological response signaling pathways. Phytocompounds such as curcumin, resveratrol, and flavonoids alter essential molecular pathways in RA pathophysiology, including nuclear factor kappa-light-chain-enhancer of activated B cells, mitogen-activated protein kinases, janus kinase-signal transducer and activator of transcription, and the inflammasome. These substances possess pro-resolving, anti-apoptotic, and antioxidant properties, which enhance their therapeutic efficacy. Alternative medicine, including dietary, herbal, and nutritional supplements, may help reduce RA symptoms. In vitro, in vivo, and clinical studies have demonstrated the effectiveness of these treatments. Phytocompounds have potential as a treatment for RA by altering signaling pathways, reducing oxidative stress, and protecting cartilage and bone. However, few clinical trials confirm its long-term safety, bioavailability, and effectiveness. Further clinical trials and translational research are needed to validate the effectiveness, safety, and pharmacokinetics of phytocompounds, while identifying novel plant-derived bioactive chemicals could improve patient outcomes.

Proteasome Inhibitors: Potential in Rheumatoid Arthritis Therapy?

Rheumatoid arthritis (RA) is a chronic autoimmune disease that leads to the destruction of peripheral joint cartilage and bone tissue. Despite the advent of biological therapies in the past decades, the complete remission of RA patients is still out of reach. Therefore, the search for novel therapeutic approaches is still open in the field of RA. Proteasome inhibitors (PIs) were originally designed to be used in hematological malignancies like multiple myeloma. However, evidence has shown that they are potent inhibitors of the NF-κB pathway, which plays a pivotal role in inflammatory processes and RA. Furthermore, inhibition of cell activation and induction of apoptosis was also reported about PIs. In the present review, we summarize the current knowledge about the potential effects of PIs in RA based on reports from animal and human studies. We believe that there is substantial potential in the use of PIs in RA therapy either alone or in combination with the medications already used.

Trends and disparities in the prevalence of diagnosed arthritis among United States adults from 2019 to 2022

Arthritis is a predominant cause of disability in the United States, imposing substantial economic burdens and public health challenges. This study aimed to analyze the trends and disparities in the prevalence of arthritis among US adults from 2019 to 2022. The National Health Interview Survey (NHIS) database of the Center for Disease Control and Prevention was analyzed, employing Joinpoint regression analysis for determining annual percentage changes (APCs) and prevalence percentages with 95% confidence intervals (CI). The prevalence of diagnosed arthritis among US adults remained relatively stable and slightly increased from 21.4% (95% CI: 20.9, 22.0) in 2019 to 21.6% (95% CI: 21.0, 22.2) in 2022 (APC: 0.4698; 95% CI: -1.0841, 2.0577). Females had a higher prevalence, which also increased from 24.3% to 25.0% (APC: 1.0218; 95% CI: -0.4408, 2.5223) with male prevalence ranging from 18.3% to 18.0% (APC: -0.3254; 95% CI: -2.6590, 2.0817). Age-related differences were particularly evident, with rates peaking in individuals aged ≥ 75 years at 53.9% in 2022. Racial disparities were observed, with White adults having a higher prevalence each year (23.8% in 2022). Geographic factors influenced prevalence, with higher rates noted in areas outside metropolitan areas and in the Midwest. Analysis of the NHIS database indicated a slight rise in arthritis prevalence overall, accompanied by notable demographic disparities. These results emphasize the necessity for tailored public health interventions and efficient disease management approaches tailored to specific populations.

Exosomal lncRNA TUG1 derived from BMSC ameliorate collagen-induced arthritis via BLIMP1-mediated Th17/Treg balance

BACKGROUND

Aberrant differentiation of Th17 cells has been identified as a critical factor in the development of rheumatoid arthritis (RA). BLIMP1 plays a key role in regulating plasma cell differentiation, T helper cell differentiation and Treg cell differentiation. Treatment with exosome injection or bone marrow mesenchymal stem cell (BMSC) transplantation reduce joint damage in RA. But the precise regulatory mechanisms remain unclear.

METHODS

We injected BMSC-derived exosomes into RA mice, and then performed histological analysis on mouse ankle joints. We cultured CD4+ T cells in vitro, then added exosomes with or without si-TUG1 and induced the differentiation of Th17 cells and Treg cells, and then we used flow cytometry to detect the ratio of Th17 cells and Treg cells. Furthermore, we injected exosomes into sh-NC or sh-BLIMP1-treated RA mice, and then performed histological analysis on the ankle joints.

RESULT

The results of our study demonstrate that exosome treatment decreased the proportion of differentiated Th17 cells, while increasing the proportion of Treg cells. And we observed that the Exo si-TUG1 group had an increased proportion of Th17 cells and a decreased proportion of Treg cells. We observed an increase in BLIMP1 expression in both the peripheral blood of mice and in CD4+ T cells cultured in vitro in the Exo group. Conversely, the Exo si-TUG1 group showed a decrease in BLIMP1 expression. Notably, inhibiting BLIMP1 expression led to the reversal of the therapeutic effects of exosomes.

CONCLUSION

Our findings suggest that BMSC-derived exosomes promote the expression of BLIMP1 through Lnc TUG1-carrying exosomes, which may modulate the balance between Th17 cells and Treg cells. This mechanism ultimately alleviates damage caused by RA, suggesting that BMSC-derived exosomes enriched in Lnc TUG1 hold promise as a potential therapeutic approach for treating RA.

Morinda officinalis iridoid glycosides, as an inhibitor of GSK-3β, alleviates rheumatoid arthritis through inhibition of NF-κB and JAK2/STAT3 pathway

Background

Morinda officinalis iridoid glycosides (MOIG) showed potential benefits in the treatment of rheumatoid arthritis (RA), but their exact mechanism has yet to be explored.

Purpose

To evaluate the effects of MOIG on RA, and explore the potential targets and molecular mechanism of MOIG in RA.

Methods

The collagen-induced arthritis (CIA) rats were used to evaluate the effects of MOIG on RA. The proliferation, migration and invasion of fibroblast-like synoviocytes (FLSs) stimulated with or without tumor necrosis factor (TNF)-α were examined by CCK-8, wound healing and transwell assays, respectively. IF and WB were applied to investigate related mechanism in FLSs. The molecular docking, molecular dynamics simulation, CETSA and siRNA were used to analyze the interaction of MOIG with target. Finally, the adjuvant-induced arthritis (AA) mice model with gene knockdown was used to confirm the effect of MOIG on glycogen synthase kinase-3β (GSK-3β).

Results

MOIG significantly alleviated the paw swelling and synovial hyperplasia in CIA rats. Moreover, MOIG suppressed proliferation, migration and invasion, the secretion of inflammatory factors, and the expression of adhesion related proteins in TNF-α-stimulated FLSs. MOIG also inhibited the activation of Janus activating kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) and nuclear factor kappa-B (NF-κB) signaling pathway in FLSs. Interestingly, the plant metabolites in MOIG had a good affinity with GSK-3β, and inhibition of GSK-3β attenuated the effects of MOIG on FLSs. Knockdown GSK-3β gene could inhibit the paw swelling and inflammatory indicators, decrease the arthritis score and synovial hyperplasia, reduce the phosphorylation of p65 and STAT3 in AA mice, thereby suppressing the NF-κB and STAT3 signaling activation, and MOIG treatment had no significant effects on AA mice with si-GSK-3β.

Conclusion

MOIG alleviates joint inflammation in RA through inhibition NF-κB and JAK2/STAT3 pathway via suppression of GSK-3β in FLSs, which provides supports for MOIG as a promising therapeutic agent of RA.

Oxypeucedanin hydrate alleviates rheumatoid arthritis by inhibiting the TLR4-MD2/NF-κB/MAPK signaling axis

Rheumatoid arthritis (RA) is an idiopathic and chronic autoimmune disease for which there are currently no effective treatments. Oxypeucedanin hydrate (OXH) is a natural coumarin known for its potent anti-inflammatory properties. However, further investigations are needed to determine its therapeutic efficacy in treating RA. In this study, we evaluate the anti-inflammatory activity of OXH by treating LPS-induced RAW264.7 macrophages. Our results show that OXH treatment reverses the changes in iNOS, COX-2, IL-1β, IL-6, and TNF-α levels. Additionally, OXH reduces ROS production. Further analysis reveals that OXH suppresses the activation of the NF-κB/MAPK pathway. CETSA results show that OXH competes with LPS for binding to the TLR4/MD2 complex. MST experiments demonstrate the specific affinity of OXH for the TLR4/MD2 complex, with a Kd value of 33.7 μM. Molecular docking analysis suggests that OXH binds to the pocket of the TLR4/MD2 complex and interacts with specific amino acids, such as GLY-343, LYS-388, and PHE-345. Molecular dynamics simulations further confirm this conclusion. Finally, we investigate the potential of OXH in treating RA using a collagen-induced arthritis (CIA) model in rats. OXH effectively ameliorates the symptoms of CIA, including improving body weight, reducing swelling and redness, increasing talus volume, and decreasing bone erosion. OXH also decreases the mRNA levels of pro-inflammatory factors in synovial tissue. Transcriptome enrichment analysis and western blot analysis confirm that OXH suppresses the NF-κB/MAPK pathway, which is consistent with our in vitro findings.

Frailty and pain, human studies and animal models

The hypothesis that pain can predispose to frailty development has been recently investigated in several clinical studies suggesting that frailty and pain may share some mechanisms. Both pain and frailty represent important clinical and social problems and both lack a successful treatment. This circumstance is mainly due to the absence of in-depth knowledge of their pathological mechanisms. Evidence of shared pathways between frailty and pain are preliminary. Indeed, many clinical studies are observational and the impact of pain treatment, and relative pain-relief, on frailty onset and progression has never been investigated. Furthermore, preclinical research on this topic has yet to be performed. Specific researches on the pain-frailty relation are needed. In this narrative review, we will attempt to point out the most relevant findings present in both clinical and preclinical literature on the topic, with particular attention to genetics, epigenetics and inflammation, in order to underline the existing gaps and the potential future interventional strategies. The use of pain and frailty animal models discussed in this review might contribute to research in this area.

Jintiange Capsule Alleviates Rheumatoid Arthritis and Reverses Changes of Serum Metabolic Profile in Collagen-Induced Arthritic Rats

Purpose

Jintiange capsule (JTG), an approved drug developed as a substitute for tiger bone (TB), has been clinically applied for osteoporosis therapy since 2003. The drug is composed of bionic TB powder, in which peptides and proteins are primarily enriched from other bone extracts. However, as a precious material of traditional Chinese medicine (TCM), TB has been mainly understood and used in TCM to relieve osteoporosis, rheumatoid arthritis and bone injury. Inspired by those, the purpose of this study was to investigate whether JTG also had an effect on relieving rheumatoid arthritis in collagen-induced arthritic (CIA) rats and explore potential mechanism from the perspective of serum metabolic profile changes.

Methods

JTG was analyzed using Nano LC-MS/MS and orally administered in CIA rats for 6 weeks. After administration, intervention effects of JTG on synovial inflammation, bone micro-architecture and bone metabolism were studied, and the impact of JTG on serum metabolic profiles in CIA rats was investigated by metabolomics.

Results

Nine bioactive peptides were identified in JTG. In animal treatments, JTG alleviated paw swelling (P < 0.01), arthritic severity (P < 0.01) and synovial tissue proliferation, as well as inflammatory cell infiltration of ankle joint, decreased bone loss, improved microstructure of bone in CIA rats by regulating bone absorption and formation, specifically increasing bone mineral density (BMD) (P < 0.05), bone volume fraction (BVF) (P < 0.05), trabecular number (Tb.N) (P < 0.05) and decreasing trabecular separation (Tb.Sp) (P < 0.05). Besides, serum IL-6 was down-regulated remarkably in CIA rats (P < 0.05). Furthermore, metabolomics analysis revealed that 32 metabolites were regulated significantly (P < 0.05) by comparison between CIA model and JTG in 360 mg/kg dose. The pathway analysis implied that JTG was involved in regulation of biosynthesis of phenylalanine.

Conclusion

JTG alleviates rheumatoid arthritis and reverses changes in serum metabolic profile in CIA rats.

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Requirements for Animal Experiments: Problems and Challenges

In vivo models remain a principle screening tool in the drug discovery pipeline. Here, the challenges associated with the need for animal experiments, as well as their impact on research, individual/societal, and economic contexts are discussed. A number of alternatives that, with further development, optimization, and investment, may replace animal experiments are also revised.

Ethyl acetate extract of Tibetan medicine Rhamnella gilgitica ameliorated type II collagen-induced arthritis in rats via regulating JAK-STAT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Rhamnella gilgitica Mansf. et Melch. (སེང་ལྡེང་།, RG) is a traditional Tibetan medicinal plant that is currently grown throughout Tibet. According to the theory of Tibetan medicine, RG is efficient for removing rheumatism, reducing swelling, and relieving pain. Hence, it has been used for the treatment of rheumatoid arthritis (RA) in Tibet for many years. However, there are no previous reports on the anti-RA activities of ethyl acetate extract of RG (RGEA).

AIM OF THE STUDY

This study aimed to explore the anti-RA effect and mechanism of RGEA on collagen-induced arthritis (CIA) in rats.

MATERIALS AND METHODS

The CIA model was established in male Wister rats by intradermal injection of bovine type II collagen and Complete Freund's Adjuvant at the base of the tail and left sole, respectively. The rats were orally administered with RGEA (9.71, 19.43, or 38.85 mg/kg) for 23 days. The body weight, swelling volume, arthritis index score, thymus and spleen indices, and pathological changes were observed to evaluate the effect of RGEA on RA. Furthermore, the inflammatory cytokines in serum, such as interleukin1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), interleukin6 (IL-6), interleukin17 (IL-17), interferon-γ (INF-γ), interleukin4 (IL-4), and interleukin10 (IL-10) were measured by enzyme linked immunosorbent assay (ELISA) to explore the anti-inflammatory effects of RGEA. The terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) staining was used to examine apoptosis. Finally, the protein and gene expression of B-cell lymphoma-2-associated X (Bax), B-cell lymphoma 2 (Bcl-2), Caspase3, janus-activated kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), suppressor of cytokine signaling1 (SOCS1), and 3 (SOCS3) in synovial tissue were detected using immunohistochemistry and real-time quantitative polymerase chain reaction (RT-qPCR).

RESULTS

After the treatment with RGEA, the body weight of rats was restored, both the arthritis index and paw swelling were suppressed, and spleen and thymus indices were decreased. RGEA reduced the inflammatory cells and synovial hyperplasia in the synovial tissue of the knee joint, and suppressed bone erosion. Meanwhile, RGEA decreased the levels of IL-1β, IL-6, IL-17, TNF-α, and INF-γ, while increased the levels of IL-4 and IL-10. TUNEL fluorescence apoptosis results confirmed that RGEA obviously promoted the apoptosis of synovial cells. Further studies showed that RGEA inhibited the proteins and mRNAs expression of JAK2 and STAT3 as well as increased the proteins and mRNAs expression of SOCS1 and SOCS3. In addition, RGEA upregulated the expression of Bax and Caspase3, and downregulated the expression of Bcl-2.

CONCLUSION

The anti-RA effectof RGEA might be related to the promotion of apoptosis and inhibition of inflammation, which regulated the JAK-STAT pathway.

Role of natural products in alleviation of rheumatoid arthritis-A review

Rheumatoid arthritis (RHA) is one of the most prevalent complex, chronic, inflammatory diseases, manifested by elevated oxidative stress and inflammatory biomarkers. Prolonged administration of NSAIDs, steroids, and DMARDs, used in the treatment of RHA, is associated with deleterious side effects. This necessitates the urge of new and safe approaches for RHA management, based on the complementary and alternative system of medicine. Documented evidences have suggested that supplementation with nutritional, dietary, and herbal components; can play a crucial role as an adjuvant, in the alleviation of the RHA symptoms, through their influence on the pathological inflammatory processes. Dietary phenolic compounds, flavonoids, carotenoids, and alkaloids with their ability to modulate prooxidant and pro-inflammatory pathways, have been effective in delaying the arthritic disease progression. Moreover, in scientific explorations, herbs containing phenolic compounds, alkaloids, carotenoids flavonoids, spices such as ginger, turmeric, Ayurvedic formulations, different diets such as Mediterranean diet, vegan diet, beverages, and oils such as sesame oil, rice bran oil, vitamins, and probiotics are proven to modulate the action of inflammatory molecules, involved in RHA pathology. Subsequently, the purpose of this review article is to summarize various in vitro, in vivo, and clinical studies in RHA, which have documented remarkable insights into the anti-inflammatory, antioxidant, analgesic, and immunomodulatory, bone erosion preventing properties of dietary, nutritional, and herbal components with the focus on their molecular level mechanisms involved in RHA. Even though major findings were derived from in vitro studies, several in vivo and clinical studies have established the use of diet, herbal, and nutritional management in RHA treatment. PRACTICAL APPLICATIONS: Thickening of the synovial membrane, bone erosion, and cartilage destruction is known to trigger rheumatoid arthritis causing inflammation and pain in bone joints. Continuous intake of NSAIDs, steroids, and DMARD therapy are associated with detrimental side effects. These side effects can be overcome by the use of dietary, nutritional, and herbal interventions based on the complementary and alternative therapy. This concept portrays the food components and other natural components having the potential to promote health, improve general well-being, and reduce the risk of RHA.

A clinical model for identifying an inflammatory phenotype in mood disorders

Increasingly, clinical research has found inflammatory correlates of psychiatric disorders, particularly mood symptomatology. Biological measures may provide greater precision in many cases and may capture clinically-relevant inflammatory signposts, such as central obesity risk, inflammation-associated co-morbid medical conditions, or proinflammatory lifestyle choices. In order to expand understanding of the role of inflammation in mood disorders, we propose a more inclusive clinical model for capturing an inflammatory phenotype of depression by identifying clinically-relevant inflammatory phenotypes grounded in biology. Our model includes chronic conditions and lifestyle behaviors associated with clinically elevated inflammation in mood disorders. Elements of this "inflamed depression" model include: obesity, low HDL concentrations, elevated triglyceride concentrations, chronically elevated blood pressure, clinical diagnosis of hypothyroidism, migraines, rheumatoid arthritis, adult onset diabetes, inflammatory bowel diseases, inflammatory skin conditions, and lifestyle factors including smoking cigarettes and chronic stress.

Tibetan medicine Kuan-Jin-Teng exerts anti-arthritic effects on collagen-induced arthritis rats via inhibition the production of pro-inflammatory cytokines and down-regulation of MAPK signaling pathway

BACKGROUND

The stems of Tinospora sinensis (Lour.) Merr commonly named "Kuan-Jin-Teng" in Chinese, have been used to treat rheumatoid arthritis as a Tibetan medicine.

PURPOSE

The effects of the EtOAc fraction of ethanolic extract from the stems of T. sinensis (KJT) on the pro-inflammatory cytokines and MAPK pathway were studied in collagen-induced arthritis (CIA) model.

STUDY DESIGN

Anti-arthritic activity of KJT was investigated in CIA model.

METHODS

The chemical constituents of KJT were analyzed by LC-MS and HPLC. The CIA model was established with injecting the bovine CII emulsified in Freund's adjuvant in Wistar rats. Several doses of KJT (50.0, 100.0 and 200.0 mg/kg) were administrated via oral gavage to CIA rats daily for 4 weeks. The anti-arthritic activity of KJT was investigated by clinical arthritis scoring, paw swelling inspection and hyperalgesia measurement, as well as radiological and histological analysis in CIA rats. The impacts of KJT on the activation of MAPK pathway, production of pro-inflammatory cytokines (TNF-α, IL-1β and IL-17) in ankle joints, serum, and spleen in CIA rats were examined by western blot, immunohistochemical staining, ELISA, and quantitative real-time PCR respectively. Lastly, the effects of KJT on production of the nitric oxide (NO) and pro-inflammatory cytokines as well as the regulation of the phosphorylation of p38 and Erk were detected in lipopolysaccharide (LPS)-stimulated RAW264.7 murine macrophage cells.

RESULTS

KJT significantly alleviated the paw swelling, hyperalgesia and arthritic severity, and reduced the synovial tissue proliferation and inflammatory cell infiltration in the CIA rats. Moreover, KJT suppressed the production of TNF-α, IL-1β, and IL-17 in ankle joints, serum, and spleen and reversed the up-regulation of the phosphorylation of p38 and Erk in CIA rats. KJT was also demonstrated to inhibit the production of NO and pro-inflammatory cytokines (TNF-α, IL-1β and IL-6), and phosphorylation of p38 and Erk in LPS-stimulated RAW264.7 cells.

CONCLUSION

These results suggest the mechanisms of KJT performing its anti-arthritis effect may be attributed to inhibiting the production of pro-inflammatory cytokines and down-regulating the MAPK signaling pathway.

Terpenes as possible drugs for the mitigation of arthritic symptoms - A systematic review

BACKGROUND

Arthritis is a syndrome associated with exacerbated inflammation, joint destruction and chronic pain and disability. Chronic treatment of arthritis is associated with several side effects and high abandonment. Therefore, there has been an ongoing search for alternative treatments to overcome these problems.

PURPOSE

Natural products, which are already widely used for their biological, cosmetic and pharmacotechnic properties, are a possible source for new drugs. Terpenes, a large class of organic compounds produced mainly by plants and trees, are a promising natural product and have already been shown to be effective in treating chronic pain, particularly of an inflammatory origin.

STUDY DESIGN AND METHODS

This review identifies the main terpenes with anti-arthritic activity reported in the last 10 years. A survey was conducted between December 2017 and June 2018 in the PUBMED, SCOPUS and Science Direct databases using combinations of the descriptors terpenes, arthritis and inflammation.

RESULTS

The results showed that terpenes have promising biological effects in relation to the treatment of arthritis, with the 24 terpenes identified in our survey being effective in the modulation of inflammatory mediators important to the physiopathology of arthritis, such as IL-6, IL-17, TNF-α, NFκB, and COX-2, among others. It is important to note that most of the studies used animal models, which limits, at least in part, the direct translation to humans of the experimental evidence produced by the studies.

CONCLUSION

Together, our finds suggest that terpenes can modulate the immuno-regulatory and destructive tissue events that underlie the clinical presentation and the progression of arthritis and are worthy of further clinical investigation.

Experimental animal models for rheumatoid arthritis

Rheumatoid Arthritis (RA) is an autoimmune systemic disorder of unknown etiology and is characterized by chronic inflammation and synovial infiltration of immune cells. RA is associated with decreased life expectancy and quality of life. The research on RA is greatly simplified by animal models that help us to investigate the complex system involving inflammation, immunological tolerance and autoimmunity. The animal models of RA with a proven track record of predictability for efficacy in humans include: collagen type II induced arthritis in rats as well as mice, adjuvant induced arthritis in rats and antigen induced arthritis in several species. The development of novel treatments for RA requires the interplay between clinical observations and studies in animal models. However, each model features a different mechanism driving the disease expression; the benefits of each should be evaluated carefully in making the appropriate choice for the scientific problem to be investigated. In this review article, we focus on animal models of arthritis induced in various species along with the genetic models. The review also discussed the similarity and dissimilarities with respect to human RA.

Mandibular movements in older people with rheumatoid arthritis

OBJECTIVE

The aim of this study was to compare the mandibular movements in older people with and without temporomandibular disorder (TMD) associated with rheumatoid arthritis (RA).

STUDY DESIGN

Thirty partially or completely edentulous older adults (65.33 ± 4.7 years) were assigned to 2 groups: (1) with RA and TMD and (2) without RA and TMD. Chewing movements of the jaws during mastication of the test material (Optocal) and the range of mandibular movements were evaluated by using the JT-3-D kinesiographic device before and after new removable prosthesis insertion. Multiple comparisons were made with analysis of variance (ANOVA) and the Tukey-Kramer test.

RESULTS

Comparisons between the 2 groups before and after new prosthesis insertion revealed that the RA and TMD group had reduced opening angles (P < .05) during chewing. After insertion of new prostheses, both groups showed increased opening and closing angles during chewing (P < .05). The mandibular range of motion results showed that patients with RA and TMD exhibited lower aperture and laterality movements (P < .05) compared with controls before and after new prosthesis insertion. However, there was an increase in aperture, lefty laterality, and protrusion values after new prosthesis insertion in both groups.

CONCLUSIONS

TMD associated with RA may impair mandibular movements. Well-fitted prostheses may improve mandibular movements in older adults, especially those with RA.

Botulinum toxin type A reduces inflammatory hypernociception induced by arthritis in the temporomadibular joint of rats

OBJECTIVE

This study aimed to investigate the antinociceptive effects of Botulinum toxin type A (BoNT-A) on persistent inflammatory hypernociception induced by arthritis in the temporomandibular joint (TMJ) of rats.

MATERIAL AND METHODS

Wistar rats were induced to persistent inflammatory hypernociception in the left TMJ. Then, animals were treated with intra-TMJ injections of BoNT-A, using doses of 3.5, 7 and 14 U/kg. Saline was used as control group. Behavioral tests were applied to evaluated the effect of BoNT-A in the inflammatory hypernociception. After that, animals were euthanized and samples from peri-articular tissues and trigeminal ganglia were obtained for further analyses.

RESULTS

BoNT-A reduced the persistent inflammatory hypernociception induced by arthritis in the TMJ of rats. BoNT-A significantly reduced the peripheral release of the neurotransmitters Substance P and Calcitonin gene related peptide; and the pro-inflammatory cytokine IL-1β. Otherwise, BoNT-A had no effect in the peripheral release of glutamate and the cytokine TNF-α.

CONCLUSION

These results demonstrate that intra-articular injection of BoNT-A reduces the albumin-induced arthritis persistent hypernociception in TMJ of rats by peripheral inhibition of neuropeptides release.

Effects of the stem extracts of Schisandra glaucescens Diels on collagen-induced arthritis in Balb/c mice

ETHNOPHARMACOLOGICAL RELEVANCE

Schisandra glaucescens Diels (SGD) is used in a subclass of traditional Chinese medicine known as "Tujia drugs". It has been long used for the treatment of rheumatoid arthritis (RA), cough with dyspnea, spontaneous sweating, night sweating, chronic diarrhea, and neurasthenia. As a woody liana growing in mountain jungles at the altitudes of 750-1800m, it is mainly distributed in Sichuan and Hubei Provinces of China.

AIM OF THE STUDY

To evaluate the antiarthritic activity of acetate (EA) and n-butanol (Bu) fractions of SGD extract on a collagen-induced arthritis mice model.

MATERIALS AND METHODS

Acute toxicity of EA and Bu fractions of SGD extract was evaluated by gavage on normal mice. Pharmacological investigations were conducted on arthritis male Balb/c mice. The animal model was induced by immunization with type II bovine collagen (CII) on the 1st and the 14th day of the experimental schedule. EA fraction (104, 312, 936mg/kg), Bu fraction (156, 469, 1407mg/kg) of SGD extract was orally administered every two days since the 15th day for 3 weeks. Progression of edema in the paws was measured using a vernier caliper every 3 days since the 10th day. At the end of the experiment, the spleen index and histological changes of the hind knee joints were investigated. Additionally, to explore the possible antirheumatic mechanisms of the EA and Bu fractions, ELISA was carried out to analyze TNF-α, IL-10, IL-6 and IL-1β in the serum.

RESULTS

The half lethal doses of both EA and Bu fractions were much higher than the dose administered in the pharmacological investigations. Oral administration of EA fraction and Bu fraction of SGD extract significantly and does-dependently inhibited type ІІ collagen induced arthritis (CIA) in mice, as indicated by the effects on paws swelling and spleen index. Histopathological examinations demonstrated that SGD effectively protected the bones and cartilages of knee joints from erosion, lesion and deformation. Besides, the serum concentrations of cytokines TNF-α, IL-1β and IL-6 were significantly lower than the ones from the vehicle control group. Respectively, while cytokine IL-10 was remarkably higher compare with the vehicle control group.

CONCLUSIONS

SGD might be a safe and effective candidate for the treatment of RA, and deserves further investigation on the chemical components in both EA and Bu fractions of SGD extract.

Anti-inflammatory effects of the extract of Gnaphalium affine D. Don in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Gnaphalium affine D. Don (GA) has been traditionally used as a medicinal herb in China for the treatment of many ailments including rheumatoid arthritis. However, the anti-arthritic mechanism of GA has still not been demonstrated. This study aims to reveal the anti-inflammatory activity and anti-arthritic mechanism of ethanol extract of G. affine D. Don.

MATERIALS AND METHODS

Anti-inflammatory potential of GA was analyzed in vivo in carrageenan induced mice paw edema (acute study). Also, in vivo study was applied in collagen-induced arthritis (CIA) rats. In vitro experiments for analyzing the anti-inflammatory potential of GA were performed on rat alveolar macrophages cell line (NR8383). Analysis of nitric oxide release in NR8383 cells was done by Griess reaction. RT-PCR and western blotting experiment was performed to analyze the expression of phosphorylated p65 and IκBα/β-actin in NF-κB pathway. The production of TNF-α, IL-1β, and COX-2 in NR8383 cells were measured by enzyme-linked immunosorbent assay. The chemical profile of GA was analyzed by HPLC-VWD.

RESULTS

GA significantly reduced the paw volume in carrageenan induced rat paw edema rat at different doses (300 and 600 mg/kg), compared with the standard indomethacin treatment. In CIA, GA can obviously ameliorate the inflammatory symptom, including cytokine, histological symptom and paw swelling. In the vitro study, GA was able to reduce the nitric oxide (NO) levels in NR8383 cells that had been stimulated with lipopolysaccharide (LPS). The level of TNF-α, IL-1β, and COX-2 was also decreased with GA treatment in NR8383 cells that had been stimulated with lipopolysaccharide (LPS). Interestingly, GA was found to decrease the level of phosphorylated p65 and IκBα in NR8383 cells. Fifteen compounds were identified by HPLC-VWD with the reference substances and verified by LC-MS.

CONCLUSIONS

The results of the experiment scientifically validated its traditional use in inflammatory conditions.

Calcitonin gene-related peptide in the joint: contributions to pain and inflammation

Arthritis is the commonest cause of disabling chronic pain, and both osteoarthritis (OA) and rheumatoid arthritis (RA) remain major burdens on both individuals and society. Peripheral release of calcitonin gene-related peptide (CGRP) contributes to the vasodilation of acute neurogenic inflammation. Contributions of CGRP to the pain and inflammation of chronic arthritis, however, are only recently being elucidated. Animal models of arthritis are revealing the molecular and pathophysiological events that accompany and lead to progression of both arthritis and pain. Peripheral actions of CGRP in the joint might contribute to both inflammation and joint afferent sensitization. CGRP and its specific receptors are expressed in joint afferents and up-regulated following arthritis induction. Peripheral CGRP release results in activation of synovial vascular cells, through which acute vasodilatation is followed by endothelial cell proliferation and angiogenesis, key features of chronic inflammation. Local administration of CGRP to the knee also increases mechanosensitivity of joint afferents, mimicking peripheral sensitization seen in arthritic joints. Increased mechanosensitivity in OA knees and pain behaviour can be reduced by peripherally acting CGRP receptor antagonists. Effects of CGRP pathway blockade on arthritic joint afferents, but not in normal joints, suggest contributions to sensitization rather than normal joint nociception. CGRP therefore might make key contributions to the transition from normal to persistent synovitis, and the progression from nociception to sensitization. Targeting CGRP or its receptors within joint tissues to prevent these undesirable transitions during early arthritis, or suppress them in established disease, might prevent persistent inflammation and relieve arthritis pain.

15-deoxy-Δ12,14-prostaglandin J2 reduces albumin-induced arthritis in temporomandibular joint of rats

The aim of this study was to evaluate the peripheral effect of 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) in albumin-induced arthritis in temporomandibular joint (TMJ) of rats. Antigen-induced arthritis (AIA) was generated in rats with methylated bovine serum albumin (mBSA) diluted in complete Freund׳s adjuvant. Pretreatment with an intra-articular injection of 15d-PGJ2 (100 ng/TMJ) before mBSA intra-articular injection (10 µg/TMJ) (challenge) in immunized rats significantly reduced the albumin-induced arthritis inflammation. The results demonstrated that 15d-PGJ2 was able to inhibit plasma extravasation, leukocyte migration and the release of inflammatory cytokines IL-6, IL-12, IL-18 and the chemokine CINC-1 in the TMJ tissues. In addition, 15d-PGJ2 was able to increase the expression of the anti-adhesive molecule CD55 and the anti-inflammatory cytokine IL-10. Taken together, it is possible to suggest that 15d-PGJ2 inhibit leukocyte infiltration and subsequently inflammatory process, through a shift in the balance of the pro- and anti-adhesive properties. Thus, 15d-PGJ2 might be used as a potential anti-inflammatory drug to treat arthritis-induced inflammation of the temporomandibular joint.

Protective effects of Huang-Lian-Jie-Du-Tang and its component group on collagen-induced arthritis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Huang-Lian-Jie-Du-Tang is a famous Traditional Chinese medicine consisting of Rhizoma coptidis (Coptis chinensis Franch, Ranunculaceae), Radix scutellariae (Scutellaria baicalensis Georgi, Labiatae), Cortex phellodendri (Phellodendron amurense Rupr. Rutaceae) and Fructus gardeniae (Gardenia jasminoide Ellis, Rubiaceae) in a weight ratio of 3:2:2:3.This formula was described by Wang Tao (in the Chinese Tang Dynasty) in his treatise "Wai Tai Mi Yao". It has been used to treat inflammation, hypertension, gastrointestinal disorders, and liver and cerebrovascular diseases in the clinical practice of Traditional Chinese medicine, especially in treating inflammation for nearly two thousand years. However, the essential compounds in it have not been identified, and the mechanisms remain to be addressed. To investigate the protective effects of HLJDT and its component group (HLJDT-CG) on collagen-induced arthritis in rats.

MATERIALS AND METHODS

CIA was established in male Wistar rats with subcutaneous injection of type II bovine collagen at the base of the tail of animals. CIA rats were treated daily with oral administration of HLJDT aqueous extracts (270 mg/kg) or HLJDT-CG (40 mg/kg) once per day from day 6 to day 28. Rats in normal and vehicle control groups were given an equal volume of vehicle (0.9% saline) and 0.025 mg/kg Dexamethasone was given to the Standard group at the same time. The protective effect of them were assessed by measuring arthritis index, swelling, the cytokines such as TNF-α, IFN-γ and IL-17 in serum, type II collagen antibodies, splenocyte proliferation and so on.

RESULTS

The results demonstrated that treatment of CIA rat with either HLJDT aqueous extracts or HLJDT-CG not only ameliorated the symptoms of arthritis, prevented joint damage but also reduced the serum levels of TNF-α, IFN-γ and IL-17 in CIA rats. Anti-CII antibodies showed the similar trend except that of IgG1. Furthermore, HLJDT aqueous extracts and HLJDT-CG administration also suppressed CII-induced proliferative response of splenocytes. More importantly, HLJDT-CG exhibited similar pharmacological activities as HLJDT aqueous extracts in all aforementioned experiments.

CONCLUSIONS

HLJDT aqueous extracts and HLJDT-CG could effectively ameliorate CII-induced arthritis and significantly suppress the immune response against CII with similar pharmacological efficacy. These findings suggest that HLJDT has therapeutic potential in RA treatment and HLJDT-CG can represent the effective-composite of HLJDT.

Intra-articular steroid injection for temporomandibular joint arthritis in juvenile idiopathic arthritis: A systematic review on efficacy and safety

OBJECTIVE

To determine the current level of evidence for the use of intra-articular corticosteroid injections (IACI) against temporomandibular joint (TMJ) arthritis in patients with juvenile idiopathic arthritis (JIA) with a particular focus on clinical and radiological improvements and safety profile.

METHODS

A comprehensive electronic search strategy was performed in all major medical databases in February 2012. Studies were selected independently by two reviewers in accordance with a pre-specified protocol and a risk of bias assessment for all included studies.

RESULTS

Ninety-four unique citations were identified of which seven remained after the inclusion criteria were applied and all of these were assessed to have a high risk of bias. The current limited level of evidence suggests potential beneficial properties of IACI in patients with TMJ arthritis-related symptoms and/or MRI-verified signs of TMJ inflammation. Currently, no scientific evidence substantiates the effect of IACI in terms of (I) improving maximal mouth opening capacity significantly, (II) reducing radiological disease progression, (III) normalising/improving mandibular growth, and (IV) increasing efficacy upon repeated injections.

CONCLUSION

The current level of evidence allows only very limited conclusions on the effect of IACI therapy in patients with TMJ arthritis. Knowledge on the long-term impact of IACI on mandibular growth is not available. Future studies designed in accordance with evidence-based standards are needed to allow a more general conclusion on efficacy and safety of this treatment modality in patients with TMJ arthritis.

Advances in research on animal models of rheumatoid arthritis

At present, rheumatoid arthritis (RA) is considered a type of autoimmune disease. Its pathology is not certain, and effective drugs with less toxicity have not been established. The establishment and application of animal models are effective methods for RA research, especially using animal models similar to humans. Arthritis is more heterogeneous, and this is an important starting point when discussing animal models for arthritis. Animal models are instrumental in understanding the etiology and pathogenetic mechanisms of RA. Appropriate animal models should be selected according to experiments because they have different traits. Various methods have been applied to induce arthritis in animal experimental models, which have provided important insights into the etiopathogenetic mechanisms of human RA. This review was written to give a broad introduction of the current stage of RA model and hope to offer beneficial help for RA-related research.

Predictive validity of behavioural animal models for chronic pain

Rodent models of chronic pain may elucidate pathophysiological mechanisms and identify potential drug targets, but whether they predict clinical efficacy of novel compounds is controversial. Several potential analgesics have failed in clinical trials, in spite of strong animal modelling support for efficacy, but there are also examples of successful modelling. Significant differences in how methods are implemented and results are reported means that a literature-based comparison between preclinical data and clinical trials will not reveal whether a particular model is generally predictive. Limited reports on negative outcomes prevents reliable estimate of specificity of any model. Animal models tend to be validated with standard analgesics and may be biased towards tractable pain mechanisms. But preclinical publications rarely contain drug exposure data, and drugs are usually given in high doses and as a single administration, which may lead to drug distribution and exposure deviating significantly from clinical conditions. The greatest challenge for predictive modelling is, however, the heterogeneity of the target patient populations, in terms of both symptoms and pharmacology, probably reflecting differences in pathophysiology. In well-controlled clinical trials, a majority of patients shows less than 50% reduction in pain. A model that responds well to current analgesics should therefore predict efficacy only in a subset of patients within a diagnostic group. It follows that successful translation requires several models for each indication, reflecting critical pathophysiological processes, combined with data linking exposure levels with effect on target.

Applications of proteomics to osteoarthritis, a musculoskeletal disease characterized by aging

The incidence of age-related musculoskeletal impairment is steadily rising throughout the world. Musculoskeletal conditions are closely linked with aging and inflammation. They are leading causes of morbidity and disability in man and beast. Aging is a major contributor to musculoskeletal degeneration and the development of osteoarthritis (OA). OA is a degenerative disease that involves structural changes to joint tissues including synovial inflammation, catabolic destruction of articular cartilage and alterations in subchondral bone. Cartilage degradation and structural changes in subchondral bone result in the production of fragments of extracellular matrix molecules. Some of these biochemical markers or "biomarkers" can be detected in blood, serum, synovial fluid, and urine and may be useful markers of disease progression. The ability to detect biomarkers of cartilage degradation in body fluids may enable clinicians to diagnose sub-clinical OA as well as determining the course of disease progression. New biomarkers that indicate early responses of the joint cartilage to degeneration will be useful in detecting early, pre-radiographic changes. Systems biology is increasingly applied in basic cartilage biology and OA research. Proteomic techniques have the potential to improve our understanding of OA physiopathology and its underlying mechanisms. Proteomics can also facilitate the discovery of disease-specific biomarkers and help identify new therapeutic targets. Proteomic studies of cartilage and other joint tissues may be particularly relevant in diagnostic orthopedics and therapeutic research. This perspective article discusses the relevance and potential of proteomics for studying age-related musculoskeletal diseases such as OA and reviews the contributions of key investigators in the field.

Characterization of a novel and spontaneous mouse model of inflammatory arthritis

Arthritis is a heterogeneous disease comprising a group of inflammatory and non-inflammatory conditions that can cause pain, stiffness and swelling in the joints. Mouse models of rheumatoid arthritis (RA) have been critical for identifying genetic and cellular mechanisms of RA and several new mouse models have been produced. Various methods have been applied to induce experimental models of arthritis in animals that would provide important insights into the etiopathogenetic mechanisms of human RA. Adipue and colleagues recently discovered that mice in their breeding colony spontaneously developed inflamed joints reminiscent of RA and may, therefore, have found a new model to examine pathogenic mechanisms and test new treatments for this human inflammatory disease.

Toll-like receptors as targets for immune disorders

Since the identification of the first Toll-like receptor (TLR) in humans in 1997, understanding of the molecular basis for innate immunity has increased significantly. The TLR family and downstream signalling pathways have been extensively characterised, There is now significant evidence suggesting a role for TLRs in human inflammatory and immune diseases such as rheumatoid arthritis, diabetes, allergy/asthma and atherosclerosis. Various approaches have been taken to identify novel therapeutic agents targeting TLRs including biologics, small molecules and nucleic acid-based drugs. Several are now being evaluated in the clinic and showing promise against various diseases. This review paper outlines the recent advances in the understanding of TLR biology and highlights novel TLR agonists and antagonists in development for the treatment of immune diseases.

Interleukin-27 and interferon-gamma are involved in regulation of autoimmune arthritis

Inflammation underlying immune pathology and tissue damage involves an intricate interplay between multiple immunological and biochemical mediators. Cytokines represent the key immune mediators that trigger a cascade of reactions that drive processes such as angiogenesis and proteolytic damage to tissues. IL-17 has now been shown to be a pivotal cytokine in many autoimmune diseases, supplanting the traditional Th1-Th2 paradigm. Also, the dual role of proinflammatory IFN-γ has unraveled new complexities in the cytokine biology of such disorders. A major hurdle in fully understanding the effector pathways in these disorders is the lack of information regarding the temporal kinetics of the cytokines during the course of the disease, as well as the interplay among the key cytokines. Using an experimental model of arthritic inflammation, we demonstrate that the temporal expression of cytokines during the incubation phase is a critical determinant of disease susceptibility. The susceptible rats raised a vigorous IL-17 response early, followed by IFN-γ and IL-27 response in that sequence, whereas the resistant rats displayed an early and concurrent response to these three cytokines. Accordingly, treatment with exogenous IFN-γ/IL-27 successfully controlled arthritic inflammation and inhibited the defined mediators of inflammation, angiogenesis, cell survival, apoptosis, and tissue damage. Furthermore, IFN-γ enhanced IL-27 secretion, revealing a cooperative interplay between the two cytokines. Our results offer a novel immunobiochemical perspective on the pathogenesis of autoimmune arthritis and its therapeutic control.

Development and validation of gene therapies in autoimmune diseases: Epidemiology to animal models

Recent advancement in immunology, molecular biology, and bioinformatics has yielded extensive information on the pathophysiological mechanisms of autoimmunity, which has greatly facilitated the identification of potential therapeutic targets and the development of gene therapy in the treatment of autoimmune disease. Preclinical studies were carried out in animal models. This phenomenon is well illustrated in two prototypic animal models of autoimmune disease: the autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS) and collagen-induced arthritis (CIA) model in rheumatoid arthritis (RA). Here we discuss the current data on the development and validation of gene therapy in autoimmunity in these two models. The success in preclinical animal model studies provides the proof-of-concept of gene therapy for potential future applications in the treatment of autoimmune diseases. Furthermore, the identification of risk factors from epidemiological studies reveals further potential therapeutic targets to be examined in animal models.

Epitope spreading initiates in the CNS in two mouse models of multiple sclerosis

Introduction

Mouse models of rheumatoid arthritis (RA) have proven critical for identifying genetic and cellular mechanisms of the disease. Upon discovering mice in our breeding colony that had spontaneously developed inflamed joints reminiscent of RA, we established the novel IIJ (inherited inflamed joints) strain. The purpose of this study was to characterize the histopathological, clinical, genetic and immunological properties of the disease.

Methods

To begin the IIJ strain, an arthritic male mouse was crossed with SJL/J females. Inheritance of the phenotype was then tracked by intercrossing, backcrossing and outcrossing to other inbred strains. The histopathology of the joints and extraarticular organ systems was examined. Serum cytokines and immunoglobulins (Igs) were measured by ELISA and cytometric bead array. Transfer experiments tested whether disease could be mediated by serum alone. Finally, the cellular joint infiltrate and the composition of secondary lymphoid organs were examined by immunohistochemistry and flow cytometry.

Results

After nine generations of intercrossing, the total incidence of arthritis was 33% (304 of 932 mice), with females being affected more than males (38% vs. 28%; P < 0.001). Swelling, most notably in the large distal joints, typically became evident at an early age (mean age of 52 days). In addition to the joint pathology, which included bone and cartilage erosion, synovial hyperproliferation and a robust cellular infiltration of mostly Gr-1⁺ neutrophils, there was also evidence of systemic inflammation. IL-6 was elevated in the sera of recently arthritic mice, and extraarticular inflammation was observed histologically in multiple organs. Total serum Ig and IgG1 levels were significantly elevated in arthritic mice, and autoantibodies such as rheumatoid factor and Ig reactive to joint components (collagen type II and joint homogenate) were also detected. Nevertheless, serum failed to transfer disease. A high percentage of double-negative (CD4^-CD8^-) CD3⁺ TCRα/β⁺ T cells in the lymphoid organs of arthritic IIJ mice suggested significant disruption in the T-cell compartment.

Conclusions

Overall, these data identify the IIJ strain as a new murine model of inflammatory, possibly autoimmune, arthritis. The IIJ strain is similar, both histologically and serologically, to RA and other murine models of autoimmune arthritis. It may prove particularly useful for understanding the female bias in autoimmune diseases.