Evaluation of therapeutic targets in animal models of arthritis: How does it relate to rheumatoid arthritis?

Withaferin A Alleviates Inflammation in Animal Models of Arthritis by Inhibiting the NF-κB Pathway and Cytokine Release

Withaferin A, a steroid lactone from Withania somnifera, exhibits anti-inflammatory, immunomodulatory, and antioxidant properties. This study investigated the effects of withaferin A on collagen-induced arthritis (CIA) rats, focusing on NF-κB p65 regulation and cytokine release. Withaferin A (50 mg/kg b.wt., orally) or methotrexate (0.25 mg/kg b.wt., i.p., as a reference drug) was given to CIA rats daily for 20 days postarthritis induction. Joints were removed from nonarthritic and arthritic rats to assess the levels of NO, MPO, interleukin (IL)-1β, IL-6, IL-10, TNF-α, COX-2, and NF-κB via ELISA. Furthermore, the mRNA expression of IL-1β, IL-10, TNF-α, COX-2, iNOS, and NF-κB was also assessed through qPCR. Treatment with withaferin A significantly inhibited the levels of inflammatory cytokines and the transcription factor NF-κB; suppressed the expression of IL-1β, IL-10, TNF-α, COX-2, iNOS, and NF-κB in the joint tissue of CIA rats; and reduced cartilage and bone destruction, as shown by H&E staining. To confirm the results obtained from biochemical and molecular studies and to determine the molecular target of withaferin A, we performed a molecular simulation of the potential targets of withaferin A, which identified the NF-κB pathway as its target. These results suggested that withaferin A effectively attenuated rheumatoid arthritis progression by inhibiting the activation of the NF-κB pathway and the downstream secretion of inflammatory cytokines.

Targeted Macrophage Re-Programming: Synergistic Therapy With Methotrexate and RELA siRNA Folate-Liposome in RAW264.7 Cells and Arthritic Rats

Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by joint inflammation and destruction. Current treatments, such as Methotrexate (MTX), though effective, often face limitations such as high plasma Cmax and lack of sustained release. This study explores a synergistic approach to RA therapy using folate-liposomal co-delivery of MTX and RELA siRNA (short interfering RNA), targeting RAW264.7 macrophage repolarization via nuclear factor kappa B (NF-κB) pathway inhibition. Extensive in vitro characterizations demonstrate the stability and biocompatibility of this therapy via folate-liposomes. In the collagen-induced arthritis (CIA) rat model, treatment leads to reduced synovial inflammation and improved mobility. The combined MTX and RELA siRNA approach indirectly inhibits inflammatory cytokines, rheumatoid factor (RF), and C-reactive protein (CRP). Targeted macrophage delivery shows marked therapeutic effects in RAW264.7 murine macrophages, potentially modulating M1 to M2 polarization. This research presents a promising avenue for innovative RA therapies by inhibiting the inflammatory cascade and preventing joint damage.

Antiarthritic activity of Physalis peruviana fruit extract via inhibition of inflammatory mediators: Integrated in vitro, in vivo and in silico study

ETHNOPHARMACOLOGICAL RELEVANCE

P. peruviana fruit, native to Andean region, is cultivated worldwide for its adaptability to various soil natures and climatic conditions. It is increasingly consumed for its high nutritional profile and history of ethnomedical uses including treatment of arthritis. Little pharmacological evidences support this folk use except for previous in vitro study that reported significant inhibition of protein denaturation.

AIM OF THE STUDY

The study aims at providing new in vivo evidence on antiarthritic activity of P. peruviana fruits in vivo that justifies its traditional use through mechanism-based experiment.

MATERIAL AND METHODS

Inhibition of inflammatory mediators is considered one of the key treatments to alleviate painful symptoms of rheumatoid arthritis (RA). Anti-inflammatory activity was assessed against COX-1 and COX-2 activity in vitro. Serum TNFα, IL-1β and IL-6 were traced using in vivo model of adjuvant-induced arthritis. Gross/inflammatory changes in rat paw, relative mass indices of spleen and liver were further investigated together with joint tissue histoarchitecture. Seven metabolites from different phytochemical classes, that were previously reported in P. peruviana fruit, were evaluated in silico against TNF-α target protein (PDB ID: 2AZ5) to assess their inhibitory effect. This was followed by assessment of their drug-likeness based on Lipinski's rule according to their physicochemical and pharmacokinetic properties.

RESULTS

High dose of extract (E-1000 mg) improved adjuvant-induced cachexia and attenuated immune-inflammatory responses in paw and serum parameters, with equipotent effect to MTX, in addition to minimal side effect profile on spleen and liver. Histopathological study of knee joint tissues confirmed dose-dependent improvement in arthritic groups treated with P. peruviana fruit extracts. The insilico study recommended steroidal lactones withaperuvin E/C and hydroxywithanolide E as promising lead compounds for inhibiting TNF enzyme as evidenced by docking scores of 6.301, 5.488 and 5.763 kcal/mol, respectively, fitting as well the Lipinski's rule of drug likeness.

CONCLUSION

The study provided novel approach that rationalize folk use of P. peruviana fruit in treatment of arthritis.

Sustained release polymer and surfactant based solid dispersion of andrographolide exhibited improved solubility, dissolution, pharmacokinetics, and pharmacological activity

Andrographolide (AD) is a potent natural product with a wide range of pharmacological activities. However, it has low oral bioavailability due to poor solubility and dissolution rate. Solid dispersion (SD) is a promising technique to improve the solubility and dissolution rate of such molecules. In this study, SD formulation of AD was prepared using Kollidon-SR (KSR) and Poloxamer-407 (P-407) as carriers. SD was prepared using the solvent evaporation method and evaluated for the modulation of solubility of AD. The developed SD formulation was characterized using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier transform infrared spectroscopy (FTIR). Further, dissolution rate, yield, drug content, stability, flowability, and pharmacokinetic profile of SD were evaluated. The compatibility of SD with the Caco-2 cells and its impact on the P-glycoprotein (P-gp) mediated efflux was also investigated. Furthermore, carrageenan-induced paw edema, and adjuvant-induced arthritic model were used to evaluate the efficacy of SD. The results showed that SD3 (AD + KSR + P-407, 1:6:8) exhibited the highest solubility and dissolution rate, and significantly improved pharmacokinetic profile compared to native AD. SD3 was found to be stable during storage and displayed excellent yield, drug content, and flowability. This formulation was found to be compatible with the Caco-2 cells and retarded the efflux of P-gp substrate. SD3 also demonstrated substantially better efficacy than native AD in terms of paw edema inhibition (carrageenan-induced paw edema, Wistar rats), and overall improvement of disease condition (in terms of paw edema, arthritic score, AST, ALT, cytokines, radiological changes, and histopathology) in arthritic Wistar rats. In conclusion, SD3 exhibited improved solubility, dissolution rate, pharmacokinetic profile, and pharmacological activity than native AD.

Comprehensive phytochemical characterization of Persea americana Mill. fruit via UPLC/HR-ESI-MS/MS and anti-arthritic evaluation using adjuvant-induced arthritis model

Persea americana Mill. (avocado fruit) has many health benefits when added to our diet due to various pharmacological activities, such as preventing bone loss and inflammation, modulating immune response and acting as an antioxidant. In the current study, the total ethanol extract (TEE) of the fruit was investigated for in vitro antioxidant and anti-inflammatory activity via DPPH and cyclooxygenase enzyme inhibition. Biological evaluation of the antiarthritic effect of the fruit extract was further investigated in vivo using Complete Freund's Adjuvant (CFA) arthritis model, where the average percentages of body weight change, inhibition of paw edema, basal paw diameter/weight and spleen index were estimated for all animal groups. Inflammatory mediators such as serum IL-6 and TNF-α were also determined, in addition to histopathological examination of the dissected limbs isolated from all experimental animals. Eighty-one metabolites belonging to different chemical classes were detected in the TEE of P. americana fruit via UPLC/HR-ESI-MS/MS. Two classes of lyso-glycerophospholipids; lyso-glycerophosphoethanolamines and lysoglycerophosphocholines were detected for the first time in avocado fruit in the positive mode. The TEE of fruit exhibited significant antioxidant and anti-inflammatory activity in vitro. In vivo anti-arthritic activity of the fruit TEE improved paw parameters, inflammatory mediators and spleen index. Histopathological findings showed marked improvements in the arthritic condition of the excised limbs. Therefore, avocado fruit could be proposed to be a powerful antioxidant and antiarthritic natural product.

Precise Lipidomics Decipher Circulating Ceramide and Sphingomyelin Cycle Associated with the Progression of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a long-term autoimmune condition that causes joint and surrounding tissue inflammation. Lipid mediators are involved in inflammation and deterioration of the joints. Despite attempts to discover effective drug targets to intervene with lipid metabolism in the disease, progress has been limited. In this study, precise lipidomic technology was employed to quantify a broad range of serum ceramides and sphingomyelin (SM) in a large cohort, revealing an association between the accumulation of circulating ceramides and disturbed ceramide/SM cycles during the progression of RA. In our investigation, we discovered that eight ceramides exhibited a positive correlation with the activity of RA, thereby enhancing the accuracy of RA diagnosis, particularly in patients with serum antibody-negative RA. Furthermore, the enzyme SM phosphodiesterase 3 (SMPD3) was found to disrupt the circulating SM cycle and accelerate the progression of RA. The activity of SMPD3 can be inhibited by methotrexate, resulting in decreased metabolic conversion of SM to ceramide. These findings suggest that targeting the SM cycle may provide a new therapeutic option for RA.

Lipid Nano-System Based Topical Drug Delivery for Management of Rheumatoid Arthritis: An Overview

The overall purpose of rheumatoid arthritis (RA) treatment is to give symptomatic alleviation; there is no recognized cure for RA. Frequent use of potent drugs like non-steroidal anti-inflammatory drugs (NSAIDs) and disease-modifying antirheumatic drugs (DMARDs), lead to various adverse effects and patient compliance suffers. On the other hand, there are many drawbacks associated with traditional methods, such as high first pass, high clearance rate, and low bioavailability. Drug administration through the skin can be a promising alternative to cope with these drawbacks, increasing patient compliance and providing site-specific action. The stratum corneum, the uppermost non-viable epidermal layer, is one of the primary limiting barriers to skin penetration. Various nanocarrier technologies come into play as drug vehicles to help overcome these barriers. The nanocarrier systems are biocompatible, stable, and have a lower cytotoxic impact. The review discusses several lipid-based nanocarrier systems for anti-rheumatic medicines for topical administration it also discusses in-vivo animal models for RA and provides information on patents granted.

GTS-21 alleviates murine collagen-induced arthritis through inhibition of peripheral monocyte trafficking into the synovium

Emerging preclinical and clinical evidence reveals a critical role for the cholinergic anti-inflammatory pathway (CAP) in mediating rheumatoid arthritis (RA). Activation of CAP via vagus nerve stimulation or alpha 7 nicotinic acetylcholine receptor (α7nAChR) agonists has previously been shown to significantly reduce inflammation and improve outcomes in animal models of experimental arthritis. In this study, we sought to determine the protective mechanism of CAP on inflammatory arthritis, specifically RA, by using a selective α7nAChR agonist, GTS-21, to examine the role of CAP in the recruitment of monocytes/macrophages into the synovium in a collagen-induced arthritis (CIA) mouse model. We found that GTS-21 ameliorated systemic and local synovial inflammation, thereby reducing synovial macrophage infiltration in CIA mice. Using in vivo imaging, we further demonstrated that GTS-21 suppressed the trafficking of monocytes into inflamed joints, while our in vitro Transwell assay data confirmed that GTS-21 reduced the migratory ability of monocytes. In addition, we found that GTS-21 reduced the number of peripheral inflammatory monocytes and down-regulated expression of the chemokines CCR2 and CCR5 on monocytes and CCL2 in the paw tissue. GTS-21 also mediated the expression levels of the adhesion molecules LFA-1 and VLA-4 on monocytes and VCAM-1 in the paw tissue, thereby blocking monocyte adhesion to the extracellular matrix. Together, our data demonstrate that GTS-21 alleviates arthritis by inhibiting peripheral monocyte trafficking into the synovium. Our findings describe a novel mechanism through which the cholinergic signaling pathway can reduce synovial inflammation in RA patients.

S100A8/A9-alarmin promotes local myeloid-derived suppressor cell activation restricting severe autoimmune arthritis

Immune-suppressive effects of myeloid-derived suppressor cells (MDSCs) are well characterized during anti-tumor immunity. The complex mechanisms promoting MDSC development and their regulatory effects during autoimmune diseases are less understood. We demonstrate that the endogenous alarmin S100A8/A9 reprograms myeloid cells to a T cell suppressing phenotype during autoimmune arthritis. Treatment of myeloid precursors with S100-alarmins during differentiation induces MDSCs in a Toll-like receptor 4-dependent manner. Consequently, knockout of S100A8/A9 aggravates disease activity in collagen-induced arthritis due to a deficit of MDSCs in local lymph nodes, which could be corrected by adoptive transfer of S100-induced MDSCs. Blockade of MDSC function in vivo aggravates disease severity in arthritis. Therapeutic application of S100A8 induces MDSCs in vivo and suppresses the inflammatory phenotype of S100A9ko mice. Accordingly, the interplay of T cell-mediated autoimmunity with a defective innate immune regulation is crucial for autoimmune arthritis, which should be considered for future innovative therapeutic options.

A sustained-release phospholipid-based phase separation gel loaded with berberine for treating rheumatoid arthritis

Berberine (BBR) has a long history of use in the treatment of Rheumatoid arthritis (RA) and is considered one of the most promising natural product for the treatment of RA. However, oral administration of berberine has low bioavailability and requires frequent administration, resulting in poor patient compliance. In this study, we developed a BBR-loaded phospholipid-based phase separation gel (BBR-PPSG) to achieve sustained drug release and long-term therapeutic effect. The stability of BBR-PPSG was verified and it was found that it can be stored for a long time. The pharmacokinetic study on rats and rabbits showed that BBR-PPSG not only achieved 1-month of sustained release, but also significantly increased the area under the curve (AUC) by nearly 9-fold and prolonged the half-life (t1/2) by 10-fold. By constructing rat and rabbit models of RA, we also proved that BBR-PPSG administration once a month effectively alleviated joint swelling, and significantly reduce TNF-α levels in AIA rats and OIA rabbits. Histopathological analysis of rabbit joint sections revealed that after intra-articular injection of BBR-PPSG, the synovial cell layer remained intact, while in the model group, the synovial cells were significantly reduced and exhibited necrosis. MicroCT data analysis showed that the values of Tb.N and Tb. Sp in the BBR-PPSG group were significantly better than those in the model group (p < 0.05). This study addressed the limitations of frequent administration of BBR by developing a phospholipid-based phase separation gel system for berberine delivery, achieving long-term sustained release. The BBR-PPSG demonstrated good biocompatibility, simple preparation and excellent stability, thus holding potential as a novel pharmaceutical formulation for RA treatment.

Rhodiola rosea L. Extract, a Known Adaptogen, Evaluated in Experimental Arthritis

Rhodiola rosea L. extract (RSE) is mostly known for its adaptogen properties, but not for its antiarthritic activities, therefore monotherapy and combination with low-dose methotrexate (MTX) was studied. The collagen-induced arthritis (CIA) model was used to measure the functional score, and the change in hind paw volume (HPV). Both parameters had significant antiarthritic effects. Based on these preliminary results, an adjuvant arthritis (AA) model was further applied to assess another parameters. The experiment included these animal groups: healthy controls, untreated AA, AA administered with RSE (150 mg/kg b.w. daily, p.o.), AA administered by MTX (0.3 mg/kg b.w. twice a week, p.o.), and AA treated with the combination of RSE+MTX. The combination of RSE+MTX significantly reduced the HPV and increased the body weight. The combination significantly decreased HPV when compared to MTX monotherapy. The plasmatic levels of inflammatory markers (IL-6, IL-17A, MMP-9 and CRP) were significantly decreased by MTX+RSE treatment. The RSE monotherapy didn't influence any of the inflammatory parameters studied. In CIA, the RSE monotherapy significantly decreased the arthritic parameters studied. In summary, the combination of RSE and sub-therapeutic MTX was significantly effective in AA by improving inflammatory and arthritic parameters.

Mesenchymal Stem Cells and Myeloid-Derived Suppressor Cells Interplay in Adjuvant-Induced Arthritis Rat Model

There has not been much researchs on the biological relationship between myeloid-derived suppressor cells (MDSCs) and mesenchymal stem cells (MSCs). The goal of the current work is to examine how these cells cooperate with one another in a rat model of adjuvant-induced arthritis (AIA). Three groups of equal numbers of rats were created; the first group served as the control. Complete Freund's adjuvant (CFA) was injected into the second group to induce AIA. The third group underwent MSCstreatment. Three weeks later, ANA, IL-1β, IL-4, IL-6, IL-10, TNF-α, IFN-γ, M-CSF, iNOS and Arg-1 were determined using ELISA. Flowcytometric studies for MDSCs using CD11bc + and His48 + antibodies were performed. Current results showed significantly higher levels of WBCs, ANA, IL-1, IL-4, IL-6, IL-10, TNF-α, M-CSF, iNOS and Arg-1 along with a significant rise in MDSCs % in the AIA group compared to the control group. As opposed to AIA animals, MSCs administration resulted in a considerable improvement in cytokine levels, supporting the immunomodulation function of MSCs. Histological examination of the joints in the AIA group revealed articular cartilage degradation as well as infiltration of inflammatory cells and fibroplasia. These several evidences suggested that MDSCs may perform various roles in autoimmunity. Understanding how MDSCs and MSCs contribute to arthritis may help their prospective application in immunotherapy. Therefore, the reciprocal collaboration of MSCs and MDSCs must therefore be the subject of new investigations, which can offer new platforms for the development of more effective and individualized therapies for the treatment of immunological illnesses.

Aberrant pro-inflammatory responses of CD20+ T cells in experimental arthritis

CD20+ T cells comprise a highly inflammatory subset implicated in autoimmunity, including rheumatoid arthritis (RA). We sought to characterize the CD20+ T cell subset in the murine collagen-induced arthritis (CIA) model of RA and investigate the phenotype and functional relevance of CD3+CD20+ T cells in the lymph nodes and arthritic joints using flow cytometry and immunohistochemistry. We demonstrate that CD3+CD4+CD20+ and CD3+CD8+CD20+ T cells are expanded in the draining lymph nodes of CIA mice, produce increased levels of pro-inflammatory cytokines and are less susceptible to regulation by regulatory T cells. Notably, CD3+CD4+CD20+ and CD3+CD8+CD20+ T cells are enriched with CXCR5+PD-1+ T follicular helper cells and CXCR5-PD-1+ peripheral T helper cells, subsets of T cells implicated in promoting B-cell responses and antibody production within pathologically inflamed non-lymphoid tissues in RA. Our findings suggest CD20+ T cells are associated with inflammatory responses and may exacerbate pathology by promoting inflammatory B-cell responses.

Engineering approaches to investigate the roles of lymphatics vessels in rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the most common chronic inflammatory joint disorders. While our understanding of the autoimmune processes that lead to synovial degradation has improved, a majority of patients are still resistant to current treatments and require new therapeutics. An understudied and promising area for therapy involves the roles of lymphatic vessels (LVs) in RA progression, which has been observed to have a significant effect on mediating chronic inflammation. RA disease progression has been shown to correlate with dramatic changes in LV structure and interstitial fluid drainage, manifesting in the retention of distinct immune cell phenotypes within the synovium. Advances in dynamic imaging technologies have demonstrated that LVs in RA undergo an initial expansion phase of increased LVs and abnormal contractions followed by a collapsed phase of reduced lymphatic function and immune cell clearance in vivo. However, current animal models of RA fail to decouple biological and biophysical factors that might be responsible for this lymphatic dysfunction in RA, and a few attempted in vitro models of the synovium in RA have not yet included the contributions from the LVs. Various methods of replicating LVs in vitro have been developed to study lymphatic biology, but these have yet not been integrated into the RA context. This review discusses the roles of LVs in RA and the current engineering approaches to improve our understanding of lymphatic pathophysiology in RA.

Fluorinated polyamidoamine dendrimer-mediated miR-23b delivery for the treatment of experimental rheumatoid arthritis in rats

In rheumatoid arthritis (RA), insufficient apoptosis of macrophages and excessive generation of pro-inflammatory cytokines are intimately connected, accelerating the development of disease. Here, a fluorinated polyamidoamine dendrimer (FP) is used to deliver miR-23b to reduce inflammation by triggering the apoptosis of as well as inhibiting the inflammatory response in macrophages. Following the intravenous injection of FP/miR-23b nanoparticles in experimental RA models, the nanoparticles show therapeutic efficacy with inhibition of inflammatory response, reduced bone and cartilage erosion, suppression of synoviocyte infiltration and the recovery of mobility. Moreover, the nanoparticles accumulate in the inflamed joint and are non-specifically captured by synoviocytes, leading to the restoration of miR-23b expression in the synovium. The miR-23b nanoparticles target Tab2, Tab3 and Ikka to regulate the activation of NF-κB pathway in the hyperplastic synovium, thereby promoting anti-inflammatory and anti-proliferative responses. Additionally, the intravenous administration of FP/miR-23b nanoparticles do not induce obvious systemic toxicity. Overall, our work demonstrates that the combination of apoptosis induction and inflammatory inhibition could be a promising approach in the treatment of RA and possibly other autoimmune diseases.

Rat resistance to rheumatoid arthritis induction as a function of the early-phase adrenal-pineal crosstalk

Chronic inflammatory diseases are triggered by causal stimuli that might occur long before the appearance of the symptoms. Increasing evidence suggests that these stimuli are necessary but not always sufficient to induce the diseases. The murine model of type II collagen emulsified in Freund's incomplete adjuvant (collagen-induced arthritis) to induce rheumatoid arthritis (RA) follows this pattern as some animals do not develop the chronically inflamed phenotype. Considering that in the immune-pineal axis (IPA) theory adrenal-pineal cross-talk adjusts early phases of inflammatory processes, we investigated whether differences in IPA activation could explain why some animals are resistant (RES) while others develop RA. We observed a similar increase in 6-sulfatoxymelatonin (aMT6s) excretion from day 3 to 13 in both RES and RA animals, followed by a significant decrease in RA animals. This pattern of aMT6s excretion positively correlated with plasma corticosterone (CORT) in RES animals. Additionally, RA animals presented a lower aMT6s/CORT ratio than saline-injected or RES animals. Plasmatic levels of tumour necrosis factor were similar in both groups, but interleukin (IL)-1β and monocyte chemotactic protein 1 (MCP-1) levels were lower in RES compared to RA animals. IL-2 and IL-4 were decreased in RES animals compared to saline-injected animals. The aMT6s/CORT ratio inversely correlated with the paw thickness and the inflammatory score (levels of IL-1β, MCP-1, IL-2 and IL-4 combined). Thus, adrenocortical-pineal positive interaction is an early defence mechanism for avoiding inflammatory chronification. KEY POINTS: Immune-pineal axis imbalance is observed in early-phase rheumatoid arthritis development. Only resistant animals present a positive association between adrenal and pineal hormones. The 6-sulfatoxymelatonin/corticosterone ratio is decreased in animals that develop rheumatoid arthritis. The inflammatory score combining the levels of nocturnal interleukin (IL)-1β, monocyte chemotactic protein 1, IL-2 and IL-4 presents a very strong positive correlation with the size of inflammatory lesion. The 6-sulfatoxymelatonin/corticosterone ratio presents a strong negative correlation with the inflammatory score and paw oedema size.

Mitigative effect of caffeine against diclofenac-induced hepato-renal damage and chromosomal aberrations in male albino rats

BACKGROUND

Among the most commonly consumed non-steroidal anti-inflammatory drugs (NSAID) is Diclofenac (Dic), especially in low-income countries due to its high efficiency and affordable price. However, the continuous administration of Diclofenac may induce toxic effects on various body organs including the liver and kidney. Caffeine (Caf) (1,3,7-trimethylxanthine) is a pharmacologically active alkaloid type with antioxidant and anti-inflammatory actions.

AIM

The current study aims to evaluate the ameliorative effect of Caffeine against Dic-induced hepato-renal toxicity and damage.

METHODS

Twenty-four male albino rats type were assigned randomly into four groups (n = 6): (Group 1): Control group, (Group 2): Six male rats were exposed to Dic 10 mg/kg intraperitoneally (I.P) for 28 days, (Group 3): Six male rats were exposed to Caf (15 mg/kg orally) for 28 days; (Groups 4): Six male rats were exposed to Dic (10 mg/kg, i.p) + Caf (15 mg/kg, orally) for 28 days. Histopathological study and various biological parameters were estimated among the four groups including hemoglobin (Hb%) red blood cells (RBCs), Hematocrit (HT%), total leucocyte count (WBCs), lipid peroxidation (LPO), glutathione peroxidase (GPx), alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, creatinine, tumor necrosis factor-α (TNF-α), and nitric oxide (NO).

RESULTS

The administration of Diclofenac resulted in significant deteriorations in the histopathological findings and estimated biological parameters. Whereas, daily Caffeine administration ameliorated Diclofenac-induced toxicity in the kidney and liver by three mechanisms including antioxidant, anti-inflammatory, and DNA damage inhibition.

CONCLUSION

The current study demonstrated the promising ameliorative and protective effects of Caffeine against Diclofenac-induced hepatic and renal injury.

Bench to Bedside: Modelling Inflammatory Arthritis

Inflammatory arthritides such as rheumatoid arthritis are a major cause of disability. Pre-clinical murine models of inflammatory arthritis continue to be invaluable tools with which to identify and validate therapeutic targets and compounds. The models used are well-characterised and, whilst none truly recapitulates the human disease, they are crucial to researchers seeking to identify novel therapeutic targets and to test efficacy during preclinical trials of novel drug candidates. The arthritis parameters recorded during clinical trials and routine clinical patient care have been carefully standardised, allowing comparison between centres, trials, and treatments. Similar standardisation of scoring across in vivo models has not occurred, which makes interpretation of published results, and comparison between arthritis models, challenging. Here, we include a detailed and readily implementable arthritis scoring system, that increases the breadth of arthritis characteristics captured during experimental arthritis and supports responsive and adaptive monitoring of disease progression in murine models of inflammatory arthritis. In addition, we reference the wider ethical and experimental factors researchers should consider during the experimental design phase, with emphasis on the continued importance of replacement, reduction, and refinement of animal usage in arthritis research.

Morus mesozygia leaf extract ameliorates behavioral deficits, oxidative stress and inflammation in Complete Freund's adjuvant-induced arthritis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Morus mesozygia Stapf (Moraceae), otherwise referred to as African mulberry, is utilized domestically as a remedy for a variety of inflammatory disorders including rheumatism.

AIM

The anti-arthritic effect of the ethylacetate fraction of M. mesozygia leaf extract (EAFMm) was assessed on complete Freund's adjuvant (CFA)-induced arthritis in male Wistar rats.

METHOD

Groups of male Wistar rats were injected with CFA (0.2 mL; 10 mg/mL) in the plantar surface of their right hind paws and treated orally with EAFMm (50 and 100 mg/kg) or its vehicle daily for 28 days. The effect on joint inflammation and mechanical nociception threshold, behavioral deficits (spontaneous motor activity in the open field test and depressive-like symptoms in the forced swim test) was evaluated. The levels and activities of the biomarkers of oxidative-nitrosative stress (reduced glutathione, superoxide dismutase, nitrite, and malondialdehyde) and inflammatory markers [TNF-α, IL-6, COX-2, NFκB and myeloperoxidase] were also analysed.

RESULTS

The EAFMm at the doses of 50 and 100 mg/kg produced a dose dependent reduction in joint inflammation and mechanical hyperalgesia, and as well improved behavioral deficits like spontaneous motor activity and depressive-like behavior. The EAFMm also significantly reduced oxido-nitrosative stress response in the joint and brain tissues. It also decreased TNF-α, interleukin-6 levels and myeloperoxidase enzyme activities in joints and brain tissues of rats. Furthermore, EAFMm attenuated the activity of NFκB and reduced the cyclooxygenase -2 protein expression level in joint tissues.

CONCLUSION

The ethylacetate fraction of Morus mesozygia leaf extract demonstrated anti-arthritic activity and ameliorated co-morbid depressive-like behavior via inhibition of oxidative stress and inflammation in a rat model of arthritis.

Bioavailability, anti-inflammatory and anti-arthritic effect of Acetyl Keto Boswellic acid and its combination with methotrexate in an arthritic animal model

ETHNOPHARMACOLOGICAL RELEVANCE

Rheumatoid arthritis is one of the most common disabling chronic progressive autoimmune diseases affecting the adult world population. Boswellia serrata has been a known anti-inflammatory agent since ancient times. Therefore, research on Boswellia extract based on Acetyl Keto Boswellic Acid (AKBA) content evaluating its efficacy and safety is necessary. The study aimed to find a suitable Boswellia extract rich in AKBA to evaluate its bioavailability, anti-inflammatory, and anti-arthritic effect. In addition, the synergistic action of AKBA extract with methotrexate (MTX) was also assessed on an animal model.

MATERIALS AND METHODS

Oral bioavailability of AKBA and the anti-inflammatory activity of 10% AKBA (5, 10, 20, 40 mg/kg b.w) was assessed and compared with 2% AKBA (40 mg/kg) and diclofenac (10 mg/kg). The effect of 10% AKBA at 20 mg/kg and 40 mg/kg was evaluated in the FCA induced arthritis animal model alone and combined with methotrexate (MTX) at 2 mg/kg b.w. Subplantar injection of FCA produced edema within a few hours with progressive arthritis by the 9th day after injection. All the treatments were initiated from the 10th day until the 45th day. Oral administration of 10% AKBA was done daily and MTX by intraperitoneal route once a week from day 10 to day 45. Paw volume, erythrocyte sedimentation rate (ESR), serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), alkaline phosphatase (ALP), total bilirubin, oxidative markers (superoxide dismutase (SOD) levels, malondialdehyde (MDA), total proteins and liver histopathology were examined.

RESULTS

10% AKBA provided 8.48-fold, 24.22-fold, 47.36-fold, and 110.53-fold higher AUC (0-α) of AKBA at 5 mg/kg, 10 mg/kg, 20 mg/kg and 40 mg/kg, respectively compared to 2% AKBA at 40 mg/kg. Percentage paw edema inhibition of 10% AKBA at 20 mg/kg and 40 mg/kg were significantly higher than 2% regular AKBA (40 mg/kg) and diclofenac (10 mg/kg). 10% AKBA at a dose of 20 and 40 mg/kg significantly reduced ESR compared with FCA treated group. A combination of methotrexate with 10% AKBA showed the highest reduction in ESR. 10% AKBA at both dose levels significantly reduced hepatic marker enzymes and total bilirubin levels. Treatment with 10% AKBA showed a significant increase in total proteins, antioxidant enzymes and a decrease in malondialdehyde levels. Similarly, 10% AKBA protected the hepatocytes compared with the FCA and FCA + MTX treated group. 10% AKBA was capable of significantly minimizing FCA and FCA + MTX induced changes.

CONCLUSION

Anti-inflammatory activity of AKBA due to inhibition of lipoxygenase (LOX) enzymes supports the use of AKBA in inflammatory disorders. Combination therapy of 10% AKBA with MTX is effective in inhibiting arthritis and circumventing hepatotoxicity produced by MTX in arthritic animals.

Trichinella-induced immunomodulation: Another tale of helminth success

Trichinella spiralis is a unique parasite in that both the adults and larvae survive in two different intracellular niches in the same host. The immune response, albeit intense, is highly modulated to ensure the survival of both the host and the parasite. It is skewed to T helper 2 and regulatory arms. Diverse cells from both the innate and adaptive compartments of immunity, including dendritic cells, T regulatory cells, and alternatively activated macrophages are thought to mediate such immunomodulation. The parasite has also an outstanding ability to evade the immune system by several elaborate processes. The molecules derived from the parasites including Trichinella, particularly the components of the excretory-secretory products, are being continually identified and explored for the potential of ameliorating the immunopathology in animal models of diverse inflammatory and autoimmune human diseases. Herein we discuss the various aspects of Trichinella-induced immunomodulation with a special reference to the practical implications of the immune system manipulation in alleviating or possibly curing human diseases.

Pharmacological Inhibition of MALT1 Ameliorates Autoimmune Pathogenesis and Can Be Uncoupled From Effects on Regulatory T-Cells

MALT1 forms part of a central signaling node downstream of immunoreceptor tyrosine-based activation motif (ITAM)-containing receptors, across a broad range of immune cell subsets, and regulates NF-κB driven transcriptional responses via dual scaffolding-protease activity. Allosteric inhibition of MALT1 activity has demonstrated benefit in animal models of inflammation. However, development of MALT1 inhibitors to treat autoimmune and inflammatory diseases (A&ID) has been hindered by reports linking MALT1 inhibition and genetic loss-of-function to reductions in regulatory T-cell (Treg) numbers and development of auto-inflammatory syndromes. Using an allosteric MALT1 inhibitor, we investigated the consequence of pharmacological inhibition of MALT1 on proinflammatory cells compared to regulatory T-cells. Consistent with its known role in ITAM-driven responses, MALT1 inhibition suppressed proinflammatory cytokine production from activated human T-cells and monocyte-derived macrophages, and attenuated B-cell proliferation. Oral administration of a MALT1 inhibitor reduced disease severity and synovial cytokine production in a rat collagen-induced arthritis model. Interestingly, reduction in splenic Treg numbers was less pronounced in the context of inflammation compared with naïve animals. Additionally, in the context of the disease model, we observed an uncoupling of anti-inflammatory effects of MALT1 inhibition from Treg reduction, with lower systemic concentrations of inhibitor needed to reduce disease severity compared to that required to reduce Treg numbers. MALT1 inhibition did not affect suppressive function of human Tregs in vitro. These data indicate that anti-inflammatory efficacy can be achieved with MALT1 inhibition without impacting the number or function of Tregs, further supporting the potential of MALT1 inhibition in the treatment of autoimmune disease.

The anti-angiogenesis mechanism of Geniposide on rheumatoid arthritis is related to the regulation of PTEN

Rheumatoid arthritis (RA) is a systemic immune disease characterized by joint inflammation and pannus. The nascent pannus contributes to synovial hyperplasia, cartilage, and tissue damage in RA. This study aims to explore the therapeutic effect and potential mechanism of Geniposide (GE) on RA angiogenesis, involving the participation of phosphate and tension homology deleted on chromosome ten (PTEN) and downstream pathways. Clinical manifestations, synovial pathomorphology, microvessel density, and the level of angiogenesis-related factors were used to evaluate the therapeutic effect of GE on adjuvant-induced arthritis (AA) rats. The proliferation, migration, and tube formation of human umbilical vein endothelial cells (HUVECs) indicate the degree of angiogenesis in vitro. Lentivirus over-expression of PTEN was employed to elucidate the potential mechanism. The results showed that GE improved the degree of arthritis and angiogenesis in AA rats. The expression of PTEN was decreased significantly in vivo and in vitro, and over-expression of PTEN improved the biological function of HUVECs to inhibit angiogenesis. GE inhibited the proliferation, migration, and tubule formation of HUVECs and plays an anti-angiogenesis role in vitro. Mechanism study showed that PTEN expression was increased and p-PI3K and p-Akt expression was decreased with GE treatment. It suggests that GE up-regulated the expression of PTEN and inhibited the activation of PI3K-Akt signal, which plays a role in inhibiting angiogenesis in RA in vivo and in vitro.

The Anti-Inflammatory Effect of Cabbage Leaves Explained by the Influence of bol-miRNA172a on FAN Expression

Recently, the possibility of cross-kingdom gene expression regulation by miRNAs from other species (“xenomiRs”), specifically from plants, has acquired scientific meaning. Based on the one of oldest methods for dealing with inflammation via the use of cabbage leaf compresses, we investigated the effects of Brassica oleracea derived miR172a on the potential human target gene encoding FAN (Factor Associated with Neutral Sphingomyelinase Activation) protein. In vitro experiments showed a decrease in FAN protein levels in both human and mouse cells transfected with bol-miRNA172a. As the FAN protein mediates inflammatory responses, the potential of miR172a to mitigate the inflammatory process was tested in a mouse model of rheumatoid arthritis. Animal studies showed the decreased oedema of inflamed paws in mouse with rheumatoid arthritis model induced after treatment with miR172a.

Prophylactic or therapeutic administration of Holarrhena floribunda hydro ethanol extract suppresses complete Freund's adjuvant-induced arthritis in Sprague-Dawley rats

Background

A hydro ethanol extract of the stem bark of Holarrhena floribunda (HFE) has been shown to be effective in the management of acute inflammation. This study was to evaluate usefulness of the extract for the management of chronic inflammation in a murine model.

Methods

Arthritis was induced in Sprague-Dawley rats using Complete Freund’s Adjuvant. Anti-arthritic effect of the extract was evaluated in prophylactic and therapeutic treatment models at doses of 50, 200 and 500 mg/kg. Parameters assessed included oedema, serology of inflammatory response, bone tissue histology and haematology. Data were analysed by ANOVA and Tukey’s multiple comparisons post hoc test.

Results

HFE at 50–500 mg/kg dose-dependently [P ≥ 0.0354 (prophylactic) and P ≥ 0.0001 (therapeutic) inhibited swelling of the injected paw upon prophylactic [≤ 81.26% (P < 0.0001) or therapeutic [≤ 67.92% (P < 0.01) administration — and prevented spread of arthritis to the contralateral paw. The inflammation alleviation activity was further demonstrated by decrease in arthritis score, radiologic score and erythrocyte sedimentation rate. HFE at all doses significantly reduced serum interleukin (IL)-1α (P < 0.0197), and 500 mg/kg HFE reduced IL-6 (P = 0.0032). In contrast, serum concentrations of IL-10, protein kinase A and cyclic adenosine monophosphate were enhanced (P ≤ 0.0436). HFE consistently showed better prophylactic than therapeutic activity.

Conclusion

HFE strongly suppressed Complete Freund’s Adjuvant-induced arthritis and modulated regulators of inflammation, including IL-1α, − 6 and − 10. Taken together, the data suggest that HFE has potential for use as an agent for modulation of the inflammatory response.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12950-022-00301-2.

Triptolide inhibits cell growth and inflammatory response of fibroblast-like synoviocytes by modulating hsa-circ-0003353/microRNA-31-5p/CDK1 axis in rheumatoid arthritis

Triptolide (TPL) is an active component derived from Tripterygium wilfordii Hook F (TwHF) with therapeutic potential for rheumatoid arthritis (RA). However, the underlying mechanism of TPL is remains under-studied. Competing endogenous RNA (ceRNA) networks may participate in the response to TPL in RA. Herein, we sought to identify a TPL response-related ceRNA axis. A circular RNA (circRNA)-microRNA (miRNA)-mRNA ceRNA axis associated with the TPL response was constructed according to our previous study. Modulatory mechanisms of the ceRNA axis were ascertained through a series of experimentations. The clinical relevance of the ceRNA axis was also determined using computational models. Here, we found that TPL had excellent clinical effect on RA and promising therapeutic efficacy in experimental animals. The ceRNA axis of hsa-circ-0003353 (circ0003353), miR-31-5p, and CDK1 was identified as a candidate biomarker for the response of RA patients to TPL. TPL inhibited the viability, proliferation, and cell cycle entry of RA-fibroblast-like synoviocytes (FLSs), as well as the production of cytokines. Overexpression of circ0003353 abolished the inhibitory effects of TPL on RA-FLSs. Mechanistically, circ0003353 sponged miR-31-5p that inversely targeted CDK1 and manipulated the p21/Cyclin B axis. Additionally, consecutive rescue experiments indicated that the inhibitory impacts of TPL on RA-FLSs were dependent on the circ0003353/miR-31-5p/CDK1 axis. Molecular docking was also applied to predict the specific binding sites and binding capacity of TPL to related targets. In conclusion, the present study demonstrated that TPL repressed the cell growth and inflammatory response of RA-FLSs by mediating the expression of the circ0003353/miR-31-5p/CDK1 axis. This novel ceRNA axis may serve as a biomarker for screening RA patients who respond to TPL treatment, which holds potential applications in the diagnosis and therapy of RA.

Ultrasound-guided lymph node biopsy sampling to study the immunopathogenesis of rheumatoid arthritis: a well-tolerated valuable research tool

Background

Analyses of lymphoid organs are required to further elucidate the pathogenesis of inflammatory diseases like rheumatoid arthritis (RA). Yet, invasive tissue collection methods are scarcely applied, because they are often considered burdensome, although patients do not always consider invasive methods as a high burden. We aimed to investigate the perspectives of study participants undergoing ultrasound-guided inguinal lymph node (LN) needle biopsy sampling and determine the molecular and cellular quantity and quality of LN biopsies.

Methods

Together with patient research partners, questionnaires were developed to evaluate the motives, expectations, and experiences of participants undergoing a LN biopsy. Healthy controls and RA(-risk) patients were asked to complete these questionnaires before and after the procedure. RNA and lymphocyte yields from obtained LN biopsies were also calculated.

Results

We included 50 individuals, of which 43 (86%) reported their pre- and post-procedure experiences. The median reported pain on a 5-point Likert scale (1 not to 5 very painful) was 1. Interestingly, almost all (n = 32; 74%) study participants would undergo a second procedure and more than half (n = 23; 54%) would encourage others to take part in the LN biopsy study. Motives for current and future participation were mostly altruistic. Inguinal hematoma occurred frequently, but no other significant or unexpected complications ensued. The LN biopsies yielded sufficient and high-quality RNA and lymphocyte numbers.

Conclusions

Ultrasound-guided inguinal LN biopsy sampling is well-tolerated, safe, and provides sufficient material for further molecular and cellular analyses. Our participants’ positive experiences endorse the application of this research tool to further elucidate the pathogenesis of RA and other inflammatory diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02728-7.

Clinical-Like Cryotherapy in Acute Knee Arthritis Protects Neuromuscular Junctions of Quadriceps and Reduces Joint Inflammation in Mice

Rheumatoid arthritis is an autoimmune and inflammatory disease that affects synovial joint tissues and skeletal muscle. Clinical-like cryotherapy benefits signs of joint inflammation in knee osteoarthritis after 60 days of anterior cruciate ligament transection surgery. However, it is unknown whether it also benefits acute knee arthritis (e.g., reduces inflammatory process and protects neuromuscular junction [NMJ] and muscle fibers). We aimed to analyze the effects of clinical-like cryotherapy on NMJ and quadriceps muscle fibers in a model of acute knee arthritis. Twenty-four male C57BL/6 mice (20 to 25 g) were randomly allocated into three groups: control (mice with no intervention), antigen-induced arthritis (AIA; mice sensitized and immunized with intra-articular [i.a.] injection of methylated bovine serum albumin [mBSA]), and AIA+cryotherapy (mice sensitized, immunized with i.a. injection of mBSA, and submitted to a clinical-like cryotherapy protocol). Twenty-one days after sensitization, arthritis was induced in immunized mice via i.a. injection of mBSA (100 μg/joint). Two clinical-like cryotherapy sessions (crushed ice pack for 20 min) were applied two hours apart. The first session was applied immediately after i.a. injection of mBSA. The quadriceps was removed two hours after the second clinical-like cryotherapy session for morphological analysis of muscle fibers (cross-sectional area), frequency distribution of muscle fiber area (%), and NMJ (area, perimeter, and maximum diameter). Gene expressions of mRNA involved in NMJ signaling (γ-nAChR, α1-nAChR, ε-nAChR, Agrin-MusK-Rapsyn, α-dystrobrevin, and utrophin) and atrophy (muscle RING-finger protein-1 and Atrogin-1) pathways were analyzed. Inflammatory signs were assessed in knee joint (swelling, articular surface temperature, and neutrophil migration in synovial fluid). Regarding morphological analysis of muscle fibers, 180 to 270 and >270 μm2 classes were higher in the AIA+cryotherapy than the AIA group. Area, perimeter, and maximum diameter of NMJ also increased in the AIA+cryotherapy compared with the control group. Agrin mRNA expression increased in the AIA+cryotherapy compared with the control and AIA groups. In the atrophy pathway, Atrogin-1 increased compared with the control and AIA groups. The AIA+cryotherapy group reduced knee swelling and neutrophil migration compared with the AIA group. In conclusion, clinical-like cryotherapy increased Agrin expression, contributing to NMJ maintenance and increased Atrogin-1 expression, thus protecting NMJ and muscle fiber. Furthermore, clinical-like cryotherapy reduced inflammatory signs (swelling and neutrophil migration) of acute knee arthritis.

Omega 3 polyunsaturated fatty acids: Potential anti-inflammatory effect in a model of ovariectomy and temporomandibular joint arthritis induction in rats

OBJECTIVE

To evaluate the effect of polyunsaturated fatty acid-type omega 3 (ω3) on the temporomandibular joint (TMJ) of ovariectomized rats (OVX) with rheumatoid arthritis (RA).

DESIGN

Rheumatoid arthritis was induced using complete Freund's adjuvant and type II bovine collagen injected at the base of the tail. Twenty-four adult female rats were treated by gavage and divided into four groups: G1: Sham, treated with 0.9% NaCl; G2: OVX, treated with 0.9% NaCl; G3: OVX+RA treated with 0.9% NaCl; G4: OVX+RA+ω3 treated with omega 3 (300 mg/kg/day). The induction of rheumatoid arthritis in groups G3 and G4 was performed 21 days after OVX, treatments were started 15 days after the induction of rheumatoid arthritis, maintained for 7 days, and killed. Bilateral TMJs were removed and assigned to morphometric analysis by micro-computed tomography and immunoassay to assess levels of cytokines IL-1β, IL-6, TNF-α, and IL-10.

RESULTS

Higher levels of inflammatory cytokines were found in the G2 and G3 (P < 0.05) and anti-inflammatory cytokines in the G1 and G4. TMJ analysis by micro-computed tomography showed a higher percentage of bone volume (median - interquartile deviation) in G1 (96.2-1.1) than in the G2 (91.5-2.0, P = 0.0374) and G3 (85.1-5.2, P = 0.0001) but showed no statistically significant differences with the G4 (93.1-1.7, P = 0.79).

CONCLUSIONS

Omega 3 successfully reduced TMJ damage in rats caused by ovariectomy and induced rheumatoid arthritis, and is a promising alternative for bone repair and attenuation of inflammatory processes.

Antiarthritic activity of OA-DHZ; a gastroprotective NF-κB/MAPK/COX inhibitor

Arthritis, a primary autoimmune disorder having a global incidence of 2.03% person/year, is presently being treated by many commercially available drugs that treat symptomatically or improve the disease's clinical state; however, all the therapies pose varying amount of side effects. Therefore, it has become a fundamental need to search for therapeutics that offer better efficacy and safety profile, and the natural or nature-derived products are known for their outstanding performance in this arena. OA-DHZ, known to possess anti-inflammatory and analgesic properties, when explored for its efficacy against arthritis in adjuvant-induced arthritis (AIA) model, was found to inhibit paw edema by 34% and TNF-α, IL-6, and IL-1β by 67%, 39%, and 45% respectively when compared to diseased control. It was also able to reduce the inflamed spleen size by 45% and successfully normalized biochemical and hematological changes that followed arthritis. In vitro studies revealed that the underlying mechanism for inhibiting arthritis progression might be due to NF-κB /MAPK pathway modulation. OA-DHZ also showed selective inhibition of COX-2 in vitro while showing gastroprotective effects when evaluated for ulcerogenic and antiulcer potential in vivo. In contrast to the results obtained from in vivo experimentation, there is a disparity in the pharmacokinetic profile of OA-DHZ, where it showed low oral exposure and high clearance rate. OA-DHZ being antiarthritic acting via NF-κB /MAPK/ COX inhibition while showing gastroprotective effects, can be a suitable candidate to be in the drug pipeline and further exploration.

The Role of Glucocorticoids in Inflammatory Diseases

For more than 70 years, glucocorticoids (GCs) have been a powerful and affordable treatment option for inflammatory diseases. However, their benefits do not come without a cost, since GCs also cause side effects. Therefore, strong efforts are being made to improve their therapeutic index. In this review, we illustrate the mechanisms and target cells of GCs in the pathogenesis and treatment of some of the most frequent inflammatory disorders affecting the central nervous system, the gastrointestinal tract, the lung, and the joints, as well as graft-versus-host disease, which often develops after hematopoietic stem cell transplantation. In addition, an overview is provided of novel approaches aimed at improving GC therapy based on chemical modifications or GC delivery using nanoformulations. GCs remain a topic of highly active scientific research despite being one of the oldest class of drugs in medical use.

Anti-inflammatory, and anti-arthritic effects by the twigs of Cinnamomum cassia on complete Freund's adjuvant-induced arthritis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

The young branches of C. cassia Blume (Cinnamomi Ramulus; Guizhi; ; C. cassia twigs) have long been used as an anti-pyretic, anti-rheumatic, anti-spasmodic and stomachic in traditional medicine.

AIM OF THE STUDY

The aim of this study was to test the anti-inflammatory, anti-nociceptive, and anti-arthritic effects of Cinnamomum cassia twigs in acute and chronic arthritis rats.

MATERIALS AND METHODS

Subcutaneous injection of carrageenan for acute inflammation and complete Freund's adjuvant (CFA) for chronic arthritis was carried out in the hind paw of SD rats. The paw volume was measured by a plethysmometer; thermal hyperalgesia was tested using a thermal plantar tester; hyperalgesia was evaluated by ankle flexion evoked vocalizations. The c-Fos expression in the lumbar spinal cord was measured with the avidin-biotin-peroxidase technique. The nitric oxide (NO) generation in lipopolysaccharide (LPS)-induced RAW 264.7 cells was tested by Griess assay.

RESULTS AND DISCUSSION

An 80% ethanoic extract of the C. cassia twigs exhibited chronic anti-inflammatory and anti-arthritic activities by reducing the edema volume in the paws of CFA-induced chronic arthritis in rats. In addition, it showed analgesic effects through the recovery of the paw withdrawal latency stimulated by thermal hyperalgesia, and suppressing the vocalization scores evoked by ankle flexion in the hind paws of the arthritis rats. It also controlled c-Fos expression in the lumbar spinal cord of the arthritis rats. Moreover, the addition its 80%-ethanoic extract, specifically, its ethyl acetate fraction, powerfully suppressed the paw swelling in carrageenan-stimulated arthritis and the NO production in LPS-induced murine immune cells.

CONCLUSION

C. cassia twigs may act as a viably sufficient therapeutic or preventive candidate for osteoarthritis and rheumatoid arthritis; additionally, it could prevent gastrointestinal damage with its gastric protection.

Boswellia serrata Extract Containing 30% 3-Acetyl-11-Keto-Boswellic Acid Attenuates Inflammatory Mediators and Preserves Extracellular Matrix in Collagen-Induced Arthritis

Boswellia serrata extracts have been traditionally employed for the treatment of inflammatory diseases. In the present study, we have evaluated the mechanism of activity of Boswellin Super® FJ (BSE), a standardized extract of B. serrata containing not less than 30% 3-acetyl-11-keto-β-boswellic acid along with other β-boswellic acids. The in vitro anti-inflammatory activities were carried out in RAW 264.7 macrophages or human peripheral blood mononuclear cells stimulated with bacterial lipopolysaccharides (LPS) and treated with 1.25-5μg/ml BSE. The anti-arthritic activity of the extract was evaluated in a rat model of collagen-induced arthritis. BSE at 40 and 80mg/kg and celecoxib 10mg/kg were orally dosed for 21days. BSE showed significant (p<0.05) inhibition of inflammation (TNF-α, IL-6, nitric oxide, and COX-2 secretion) and downregulates the mRNA levels of TNF-α, IL-6, IL1-β, and inducible nitric oxide synthase in macrophages. BSE treatment reduced the levels of phosphorylated-NF-κB (P65), suggesting an anti-inflammatory activity mediated by blocking this key signal transduction pathway. In addition, BSE showed inhibition (p<0.05) of collagenase, elastase, hyaluronidase enzymes, and a reduction in reactive oxygen species and matrix-degrading proteins in RAW 264.7 macrophages stimulated with LPS. BSE treatment significantly (p<0.05) reduced the arthritic index, paw volume, and joint inflammation comparable to celecoxib in collagen-induced arthritis (CIA) in rats. The circulating anti-collagen antibodies were reduced in BSE and celecoxib-treated animals as compared to the CIA. In confirmation with in vitro data, BSE showed a significant (p<0.05) dose-dependent effect on C-reactive protein, prostaglandin E2, and erythrocyte sedimentation rate, which is widely used as a blood marker of inflammation. Further, BSE treatment suppressed the cartilage oligomeric matrix protein and significantly enhanced the hyaluronan levels in synovial fluid. As observed by collagen staining in joints, the loss of matrix proteins was lower in BSE-treated animals, suggesting that BSE could preserve the extracellular matrix in RA. The extract showed inhibition of collagenase enzyme activity in vitro, further strengthening this hypothesis. BSE treatment was found to be safe, and rats displayed no abnormal behavior or activities. The results suggest that Boswellin Super® mediates its activity by preserving matrix proteins, reducing pro-inflammatory mediators, and oxidative stress.

The effect of association of aspirin and omega 3 in rat temporomandibular joint with induced arthritis

This study aimed to evaluate the effects of omega-3 (ω3) polyunsaturated fatty acids, in association with aspirin (AA), on the morphology of cytokine release in the temporomandibular joint (TMJ) of rats induced with rheumatoid arthritis (IR) by injecting 100 μL of complete Freund's adjuvant with bovine type II collagen at the tail base. Thirty-two adult male rats were divided into treatment groups: Sham, treated with 0.9% sodium chloride (NaCl) p.o.; IR-control, treated with 0.9% NaCl p.o.; IR-ω3 treated with ω3 PUFAS (85 mg/kg/day p.o.); and IR-ω3 + AA treated with ω3 (85 mg/kg/day p.o.) + AA (20 mg/kg/day i.p.). After maintained treatment for seven days, the animals were euthanized. Bilateral TMJs from each rat were removed and one was subjected to histological immunoassays and enzyme-linked immunosorbent assays to assess interleukin (IL)-1β, tumor necrosis factor-α, and IL-10 levels. Data analysis was performed using the Kruskal-Wallis and Dunn tests. In the IR-ω3 and IR-ω3 + AA groups, the TMJ was greater than in the IR-control group (P < 0.0001). The addition of AA did not improve the effects of ω3 (P = 0.0698). Similarly, the addition of AA conferred no additional effects on the cytokine levels (P > 0.05); however, it increased the proteoglycan density, compared with ω3 alone. We found that ω3 exhibited anti-inflammatory activity in arthritic rats, and the addition of AA increased proteoglycan density, but did not affect cytokine expression.

The role of TGF-β2 in cartilage development and diseases

Transforming growth factor-beta2 (TGF-β2) is recognized as a versatile cytokine that plays a vital role in regulation of joint development, homeostasis, and diseases, but its role as a biological mechanism is understood far less than that of its counterpart, TGF-β1. Cartilage as a load-resisting structure in vertebrates however displays a fragile performance when any tissue disturbance occurs, due to its lack of blood vessels, nerves, and lymphatics. Recent reports have indicated that TGF-β2 is involved in the physiological processes of chondrocytes such as proliferation, differentiation, migration, and apoptosis, and the pathological progress of cartilage such as osteoarthritis (OA) and rheumatoid arthritis (RA). TGF-β2 also shows its potent capacity in the repair of cartilage defects by recruiting autologous mesenchymal stem cells and promoting secretion of other growth factor clusters. In addition, some pioneering studies have already considered it as a potential target in the treatment of OA and RA. This article aims to summarize the current progress of TGF-β2 in cartilage development and diseases, which might provide new cues for remodelling of cartilage defect and intervention of cartilage diseases.

Geniposide downregulates the VEGF/SphK1/S1P pathway and alleviates angiogenesis in rheumatoid arthritis in vivo and in vitro

The VEGF/SphK1/S1P pathway is closely related to angiogenesis in rheumatoid arthritis (RA), but the precise underlying mechanisms are unclear at present. Here, we explored the involvement of the VEGF/SphK1/S1P cascade in RA models and determined the effects of GE intervention. Our results showed abnormal expression of proteins related to this pathway in RA synovial tissue. Treatment with GE effectively regulated the signal axis, inhibited angiogenesis, and alleviated RA symptoms. In vitro, TNF-ɑ enhanced the VEGF/SphK1/S1P pathway in a co-culture model of fibroblast-like synoviocytes (FLS) and vascular endothelial cells (VEC). GE induced downregulation of VEGF in FLS, restored the dynamic balance of pro-/antiangiogenic factors, and suppressed SphK1/S1P signaling in VEC, resulting in lower proliferation activity, migration ability, tube formation ability, and S1P secretion ability of VEC cells. Additionally, SphK1-specific small interfering RNA (siRNA) blocked the VEGF/SphK1/S1P cascade, which can effectively alleviate the stimulatory effect of FLS on VEC and further enhanced the therapeutic effect of GE. Taken together, our results demonstrate that GE suppresses the VEGF/SphK1/S1P pathway and alleviates the stimulation of VEC by FLS, thereby preventing angiogenesis and promoting therapeutic effects against RA.

Animal models to study pathogenesis and treatments of cardiac disorders in rheumatoid arthritis: Advances and challenges for clinical translation

Although cardiac diseases such as acute myocardial infarction, heart failure and arrhythmias are the leading cause of cardiovascular complications in rheumatoid arthritis (RA), their pathogenesis is far from being understood and optimal therapeutic options to treat specifically these disorders in RA are lacking. Preclinical studies on animal models of arthritis can help to decipher the complex link between arthritis and the heart, and to identify critical pathways and novel therapeutic targets. This review presented the available data on cardiac disorders in animal models of RA, as well as the current knowledge on pathophysiology and pharmacology of these disorders. Future directions for translational studies in a cardiorheumatic perspective are proposed.

Efficacy of berberine in treatment of rheumatoid arthritis: From multiple targets to therapeutic potential

Rheumatoid arthritis is a systemic autoimmune disorder involved in persistent synovial inflammation. Berberine is a nature-derived alkaloid compound with multiple pharmacological activities in different pathologies, including RA. Recent experimental studies have clarified several determinant cellular and molecular targets of BBR in RA, and provided novel evidence supporting the promising therapeutic potential of BBR to combat RA. In this review, we recapitulate the therapeutic potential of BBR and its mechanism of action in ameliorating RA, and discuss the modulation of gut microbiota by BBR during RA. Collectively, BBR might be a promising lead drug with multi-functional activities for the therapeutic strategy of RA.

'Methyl palmitate attenuates adjuvant induced arthritis in rats by decrease of CD68 synovial macrophages

The study was designed to investigate the potential anti-arthritic effects of methyl palmitate in an adjuvant arthritis model in rats that shares many histopathological similarities with human RA. The underlying mechanism and its effect on CD68 macrophages were investigated, as a further argument to its possible efficacy in RA treatment. A normal control group was injected only with saline, arthritic group, and three treatment groups with CFA induced arthritis received methyl palmitate (MP) at three different doses (75, 150, 300 mg/kg/week for 3 weeks, intraperitoneal). The degree of ipsilateral paw swelling, ankle diameter, spleen index, thymus index and the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β were measured. In addition, the underlying molecular mechanism was investigated using CD68 expression. Methyl palpitate significantly and dose dependently decreased the arthritic symptoms as measured by ipsilateral paw volume and ankle diameter. It showed no effect on body weight but significantly decreased splenic, thymus index, serum TNF-α and IL-1β. CD68 macrophages expression and the overall synovial inflammatory cellularity were halted. Methyl palmitate exhibits significant anti-inflammatory and exerts a potential anti-arthritic effect in a rat model of adjuvant induced arthritis. Furthermore, it inhibits expression of synovial CD68 macrophage that validate its therapeutic potential adjuvant arthritis.

Bioflavonoid Robinin from Astragalus falcatus Lam. Mildly Improves the Effect of Metothrexate in Rats with Adjuvant Arthritis

Anti-inflammatory potential of orally administrated bioflavonoid-robinin, active sub-stance of original drug Flaroninum™ (FL), was investigated in the combination with methotrexate (MTX) and in monotherapy in rats suffering from adjuvant-induced arthritis (AA). Robinin (kaempferol-3-O-robinoside-7-O-rhamnoside) was isolated from the aerial parts of Astragalus falcatus Lam. The monotherapy with robinin was not efficient in alleviating symptoms of AA. The combination of MTX with robinin was similarly active as MTX alone in reducing the hind paw volume and change of body weight during the whole experiment. The combination, however, reduced plasma levels of Interleukin-17Aand activity of gamma-glutamyl transferase in joint more efficiently then MTX alone. Our results demonstrate that the novel combination of robinin and MTX mildly improved the reduction of inflammation in experimental arthritis.

Potency of Bone Marrow-Derived Mesenchymal Stem Cells and Indomethacin in Complete Freund's Adjuvant-Induced Arthritic Rats: Roles of TNF-α, IL-10, iNOS, MMP-9, and TGF-β1

Rheumatoid arthritis (RA) is an autoimmune syndrome affecting joint spaces, leading to the disabled state. Currently, there is no optimal therapy for RA except for systemic immunosuppressants that have variable undesirable effects after long-term use. Hence, the need for other treatment modalities has emerged in an attempt to develop a treating agent that is effective but without bad effects. Bone marrow-derived mesenchymal stem cells (BM-MSCs) may be an alternative medicine since they may differentiate into a variety of mesenchymal tissues including bone and cartilage. Indomethacin (IMC) could be suggested as an analgesic, anti-inflammatory, and antirheumatic potential agent against the course of RA since it possesses significant palliative effects and antipyretic properties. Therefore, our target of this study was to explore and compare the effect of BM-MSCs (1 × 10⁶ cells/rat at the 1^st, 6^th, 12^th, and 18^th days) and IMC (2 mg/kg b.w./day for 3 weeks) either alone or in combination on arthritic rats. The model of rheumatoid arthritis in rats was induced by subcutaneous injection of 0.1 mL/rat CFA into the footpad of the right hind paw. The BM-MSC intravenous injection and IMC oral administration significantly reduced the elevated right hind leg paw diameter and circumference, serum anti-CCP, and ankle joint articular tissue expressions of TNF-α, iNOS, MMP-9, and TGF-β1 while they significantly increased the lowered articular IL-10 expression in CFA-induced arthritic rats. The combinatory effect of the two treatments was the most potent. In conclusion, the treatment of RA with BM-MSCs and IMC together is more effective than the treatment with either BM-MSCs or IMC. The Th1 cytokine (TNF-α), Th2 cytokine (IL-10), iNOS, MMP-9, and TGF-β1 are important targets for mediating the antiarthritic effects of BM-MSCs and IMC in CFA-induced arthritis in rats.

Blockade of translationally controlled tumor protein attenuated the aggressiveness of fibroblast-like synoviocytes and ameliorated collagen-induced arthritis

Histamine releasing factor/translationally controlled tumor protein (HRF/TCTP) stimulates cancer progression and allergic responses, but the role of HRF/TCTP in rheumatoid arthritis (RA) remains undefined. In this study, we explored the pathogenic significance of HRF/TCTP and evaluated the therapeutic effects of HRF/TCTP blockade in RA. HRF/TCTP transgenic (TG) and knockdown (KD) mice with collagen-induced arthritis (CIA) were used to determine the experimental phenotypes of RA. HRF/TCTP levels in the sera of RA patients were measured and compared to those from patients with osteoarthritis (OA), ankylosing spondylitis, Behçet's disease, and healthy controls. HRF/TCTP expression was also assessed in the synovium and fibroblast-like synoviocytes (FLSs) obtained from RA or OA patients. Finally, we assessed the effects of HRF/TCTP and dimerized HRF/TCTP-binding peptide-2 (dTBP2), an HRF/TCTP inhibitor, in RA-FLSs and CIA mice. Our clinical, radiological, histological, and biochemical analyses indicate that inflammatory responses and joint destruction were increased in HRF/TCTP TG mice and decreased in KD mice compared to wild-type littermates. HRF/TCTP levels in the sera, synovial fluid, synovium, and FLSs were higher in patients with RA than in control groups. Serum levels of HRF/TCTP correlated well with RA disease activity. The tumor-like aggressiveness of RA-FLSs was exacerbated by HRF/TCTP stimulation and ameliorated by dTBP2 treatment. dTBP2 exerted protective and therapeutic effects in CIA mice and had no detrimental effects in a murine tuberculosis model. Our results indicate that HRF/TCTP is a novel biomarker and therapeutic target for the diagnosis and treatment of RA.

Combinatory Effects of Bone Marrow-Derived Mesenchymal Stem Cells and Indomethacin on Adjuvant-Induced Arthritis in Wistar Rats: Roles of IL-1β, IL-4, Nrf-2, and Oxidative Stress

Rheumatoid arthritis (RA) is a disorder triggered by autoimmune reactions and related with chronic inflammation and severe disability. Bone Marrow-derived Mesenchymal Stem Cells (BM-MSCs) have shown a hopeful immunomodulatory effect towards repairing cartilage and restoring joint function. Additionally, indomethacin (IMC), a nonsteroidal compound, has been considered as a potent therapeutic agent that exhibits significant antipyretic properties and analgesic effects. The target of the current research is to assess the antiarthritic efficacy of BM-MSCs (10⁶ cells/rat at 1, 6, 12 and 18 days) and IMC (2 mg/kg body weight/day for 3 weeks) either alone or concurrently administered against complete Freund's adjuvant-induced arthritic rats. Changes in paw volume, body weight, gross lesions, and antioxidant defense system, as well as oxidative stress, were assessed. The Th1 cytokine (IL-1β) serum level and Th2 cytokine (IL-4) and Nrf-2 ankle joint expression were detected. In comparison to normal rats, it was found that the CFA-induced arthritic rats exhibited significant leukocytosis and increase in paw volume, LPO level, RF, and IL-1β serum levels. In parallel, arthritic rats that received BM-MSCs and/or IMC efficiently exhibited decrease in paw edema, leukocytosis, and enhancement in the antioxidant enzymatic levels of SOD, GPx, GST, and GSH in serum besides upregulation of Nrf-2 and anti-inflammatory IL-4 expression levels in the ankle articular joint. Likewise, these analyses were more evidenced by the histopathological sections and histological score. The data also revealed that the combined administration of BM-MSC and IMC was more potent in suppressing inflammation and enhancing the anti-inflammatory pathway than each agent alone. Thus, it can be concluded that the combined therapy with BM-MSC and IMC may be used as a promising therapeutic choice after assessing their efficacy and safety in human beings with RA, and the antiarthritic effects may be mediated via modulatory effects on Th1/Th2 cytokines, ozidative stress, and Nrf-2.

Refinement and validation of infrared thermal imaging (IRT): a non-invasive technique to measure disease activity in a mouse model of rheumatoid arthritis

Background

The discovery and development of new medicines requires high-throughput screening of possible therapeutics in a specific model of the disease. Infrared thermal imaging (IRT) is a modern assessment method with extensive clinical and preclinical applications. Employing IRT in longitudinal preclinical setting to monitor arthritis onset, disease activity and therapeutic efficacies requires a standardized framework to provide reproducible quantitative data as a precondition for clinical studies.

Methods

Here, we established the accuracy and reliability of an inexpensive smartphone connected infrared (IR) camera against known temperature objects as well as certified blackbody calibration equipment. An easy to use protocol incorporating contactless image acquisition and computer-assisted data analysis was developed to detect disease-related temperature changes in a collagen-induced arthritis (CIA) mouse model and validated by comparison with two conventional methods, clinical arthritis scoring and paw thickness measurement. We implemented IRT to demonstrate the beneficial therapeutic effect of nanoparticle drug delivery versus free methotrexate (MTX) in vivo.

Results

The calibrations revealed high accuracy and reliability of the IR camera for detecting temperature changes in the rheumatoid arthritis animal model. Significant positive correlation was found between temperature changes and paw thickness measurements as the disease progressed. IRT was found to be superior over the conventional techniques specially at early arthritis onset, when it is difficult to observe subclinical signs and measure structural changes.

Conclusion

IRT proved to be a valid and unbiased method to detect temperature changes and quantify the degree of inflammation in a rapid and reproducible manner in longitudinal preclinical drug efficacy studies.

Flare-up of cytokines in rheumatoid arthritis and their role in triggering depression: Shared common function and their possible applications in treatment (Review)

Chronic illnesses are associated with an increased risk of depression and anxiety. Rheumatoid arthritis (RA) is a chronic autoimmune disease that typically causes damage to the joints. RA extensively impacts patients, both physically and psychologically. Depression is a common comorbid disorder with RA, which leads to worsened health outcomes. There are several cytokines that are active in the joints of patients with RA. Inflammatory cytokines serve important roles in the key processes in the joints, which usually cause inflammation, articular damage and other comorbidities associated with RA. The key role of inflammatory cytokines could be attributed to their interactions within signaling pathways. In RA, IL-1, and the cytokines of TNF-α, IL-6 and IL-18 are primarily involved. Furthermore, depression is hypothesized to be strongly associated with systemic inflammation, particularly with dysregulation of the cytokine network. The present review summarizes the current state of knowledge on these two diseases from the perspective of inflammation and cytokines, and emphasizes the possible bridge between them by exploring the involvement of systemic cytokines in both conditions.

Immunomodulatory effects of berberine on the inflamed joint reveal new therapeutic targets for rheumatoid arthritis management

Rheumatoid arthritis (RA) is a chronic inflammatory syndrome designated by synovial joint inflammation leading to cartilage degradation and bone damage as well as progressive disability. Synovial inflammation is promoted through the infiltration of mononuclear immune cells, dominated by CD4+ T cells, macrophages and dendritic cells (DCs), together with fibroblast-like synoviocytes (FLS), into the synovial compartment. Berberine is a bioactive isoquinoline alkaloid compound showing various pharmacological properties that are mainly attributed to immunomodulatory and anti-inflammatory effects. Several lines of experimental study have recently investigated the therapeutic potential of berberine and its underlying mechanisms in treating RA condition. The present review aimed to clarify determinant cellular and molecular targets of berberine in RA and found that berberine through modulating several signalling pathways involved in the joint inflammation, including PI3K/Akt, Wnt1/β-catenin, AMPK/lipogenesis and LPA/LPA1 /ERK/p38 MAPK can inhibit inflammatory proliferation of FLS cells, suppress DC activation and modulate Th17/Treg balance and thus prevent cartilage and bone destruction. Importantly, these molecular targets may explore new therapeutic targets for RA treatment.

Modeling Rheumatoid Arthritis In Vitro: From Experimental Feasibility to Physiological Proximity

Rheumatoid arthritis (RA) is a chronic, inflammatory, and systemic autoimmune disease that affects the connective tissue and primarily the joints. If not treated, RA ultimately leads to progressive cartilage and bone degeneration. The etiology of the pathogenesis of RA is unknown, demonstrating heterogeneity in its clinical presentation, and is associated with autoantibodies directed against modified self-epitopes. Although many models already exist for RA for preclinical research, many current model systems of arthritis have limited predictive value because they are either based on animals of phylogenetically distant origin or suffer from overly simplified in vitro culture conditions. These limitations pose considerable challenges for preclinical research and therefore clinical translation. Thus, a sophisticated experimental human-based in vitro approach mimicking RA is essential to (i) investigate key mechanisms in the pathogenesis of human RA, (ii) identify targets for new therapeutic approaches, (iii) test these approaches, (iv) facilitate the clinical transferability of results, and (v) reduce the use of laboratory animals. Here, we summarize the most commonly used in vitro models of RA and discuss their experimental feasibility and physiological proximity to the pathophysiology of human RA to highlight new human-based avenues in RA research to increase our knowledge on human pathophysiology and develop effective targeted therapies.

Arthritis and the role of endogenous glucocorticoids

Rheumatoid arthritis and osteoarthritis, the most common forms of arthritis, are chronic, painful, and disabling conditions. Although both diseases differ in etiology, they manifest in progressive joint destruction characterized by pathological changes in the articular cartilage, bone, and synovium. While the potent anti-inflammatory properties of therapeutic (i.e., exogenous) glucocorticoids have been heavily researched and are widely used in clinical practice, the role of endogenous glucocorticoids in arthritis susceptibility and disease progression remains poorly understood. Current evidence from mouse models suggests that local endogenous glucocorticoid signaling is upregulated by the pro-inflammatory microenvironment in rheumatoid arthritis and by aging-related mechanisms in osteoarthritis. Furthermore, these models indicate that endogenous glucocorticoid signaling in macrophages, mast cells, and chondrocytes has anti-inflammatory effects, while signaling in fibroblast-like synoviocytes, myocytes, osteoblasts, and osteocytes has pro-inflammatory actions in rheumatoid arthritis. Conversely, in osteoarthritis, endogenous glucocorticoid signaling in both osteoblasts and chondrocytes has destructive actions. Together these studies provide insights into the role of endogenous glucocorticoids in the pathogenesis of both inflammatory and degenerative joint disease.

Triamcinolone-Gold Nanoparticles Repolarize Synoviocytes and Macrophages in an Inflamed Synovium

Understanding the crosstalk between synoviocytes and macrophages is very important for the development of strategies to regulate inflammatory responses in an inflamed synovium. Simultaneous regulation of the pro- and anti-inflammatory responses of synoviocytes and macrophages (repolarization) is critical for the treatment of arthritis. Thus, the immune regulatory functions of an ideal nanodrug should not only decrease the pro-inflammatory response but also effectively increase the anti-inflammatory response. In this study, crosstalk between synoviocytes and macrophages was found to be significantly involved in the activation and deactivation of inflammatory responses in the synovium. Interestingly, a developed triamcinolone-gold nanoparticle (Triam-AuNP) complex both decreased the pro-inflammatory responses and increased the anti-inflammatory responses of fibroblast-like synoviocytes (FLSs) and macrophages via repolarization of macrophages from the M1 to the M2 phenotype. In contrast, triamcinolone alone only decreased the pro-inflammatory responses of FLSs and macrophages without upregulating their anti-inflammatory responses. In vitro (human), ex vivo (human), and in vivo (mouse) analyses clearly indicated that Triam-AuNPs effectively regulated the expression of both pro- and anti-inflammatory cytokines in FLSs and effectively repolarized activity of macrophages in the inflamed synovium. Furthermore, Triam-AuNPs significantly promoted cartilage regeneration, whereas triamcinolone alone did not induce either FLS anti-inflammatory activity or macrophage repolarization.