Applying refinement to the use of mice and rats in rheumatoid arthritis research

Biochanin A inhibits endothelial dysfunction induced by IL‑6‑stimulated endothelial microparticles in Perthes disease via the NFκB pathway

Endothelial dysfunction caused by the stimulation of endothelial microparticles (EMPs) by the inflammatory factor IL-6 is one of the pathogenic pathways associated with Perthes disease. The natural active product biochanin A (BCA) has an anti-inflammatory effect; however, whether it can alleviate endothelial dysfunction in Perthes disease is not known. The present in vitro experiments on human umbilical vein endothelial cells showed that 0-100 pg/ml IL-6-EMPs could induce endothelial dysfunction in a concentration-dependent manner, and the results of the Cell Counting Kit 8 assay revealed that, at concentrations of <20 µM, BCA had no cytotoxic effect. Reverse transcription-quantitative PCR demonstrated that BCA reduced the expression levels of the endothelial dysfunction indexes E-selectin and intercellular cell adhesion molecule-1 (ICAM-1) in a concentration-dependent manner. Immunofluorescence and western blotting illustrated that BCA increased the expression levels of zonula occludens-1 and decreased those of ICAM-1. Mechanistic studies showed that BCA inhibited activation of the NFκB pathway. In vivo experiments demonstrated that IL-6 was significantly increased in the rat model of ischemic necrosis of the femoral head, whereas BCA inhibited IL-6 production. Therefore, in Perthes disease, BCA may inhibit the NFκB pathway to suppress IL-6-EMP-induced endothelial dysfunction, and could thus be regarded as a potential treatment for Perthes disease.

An update of murine models and their methodologies in immune-mediated joint damage and pain research

Murine models have played an indispensable role in the understanding of rheumatic and musculoskeletal disorders (RMD), elucidating the genetic, endocrine and biomechanical pathways involved in joint pathology and associated pain. To date, the available models in RMD can be classified as induced or spontaneous, both incorporating transgenic alternatives that improve specific insights. It is worth noting that the selection of the most appropriate model together with the evaluation of their specific characteristics and technical capabilities are crucial when designing the experiments. Furthermore, it is also imperative to consistently adhere to the ethical standards concerning animal experimentation. Recognizing the inherent limitation that any model can entirely encapsulates the complexity of the pathophysiology of these conditions, the aim of this review is to provide an updated overview on the methodology of current murine models in major arthropathies and their immune-mediated pathways, addressing to basic, translational and pharmacological research in joint damage and pain.

Clinical Evaluation of Collagen-Induced Arthritis in Female Lewis Rats: A Comprehensive Analysis of Disease Progression and Severity

OBJECTIVE

The collagen-induced arthritis (CIA) model is the most commonly studied autoimmune model of rheumatoid arthritis (RA). In this study, we investigated the usefulness of collagen type II emulsified in Freund's incomplete adjuvant (CII/IFA) as a suitable method for establishing RA in Lewis rats. The aim of the present study was to present a straightforward and effective method for inducing CIA in rats.

MATERIALS AND METHODS

In this experimental study, animals were divided into two equal groups (n=5); control and CIA. Five rats were injected intradermally at the base of the tail with a 0.2 ml CII/IFA emulsion. On the seventh day, a 0.1 ml CII/IFA emulsion booster was injected. Arthritis symptoms that arose were evaluated at clinical, histological, radiological, and at protein expression levels to find out if the disease had been induced successfully.

RESULTS

Our finding showed a decreasing trend in the body weight during the RA induction period, while the arthritis score and paw thickness were increased during this period. The results of the enzyme-linked immunosorbent assay (ELISA) for serum samples revealed that the levels of proinflammatory cytokines, interleukin (IL)-1β, IL-6, IL-17, and tumor necrosis factor (TNF)-α and anti-CII IgG were significantly increased in CIA rats compared to the control group. After CIA induction, the level of anti-inflammatory protein IL-10 was decreased significantly. Radiographic examination of the hind paws showed soft tissue swelling, bone erosion, and osteophyte formation in CIA rats. Additionally, based on histological evaluations, the hind paws of the CIA group showed pannus formation, synovial hyperplasia, and bone and cartilage destruction.

CONCLUSION

It seems that CII/IFA treatment can be an appropriate and effective method to induce RA disease in Lewis rats. This well-established and well-characterized CIA model in female Lewis rats could be considered to study aspects of RA and develop novel anti-arthritic agents.

Nesting behavior is associated with body weight and grip strength loss in mice suffering from experimental arthritis

Objective animal health evaluation is essential to determine welfare and discomfort in preclinical in vivo research. Body condition scores, body weight, and grimace scales are commonly used to evaluate well-being in murine rheumatoid arthritis (RA) and osteoarthritis experiments. However, nest-building, a natural behavior in mice, has not yet been evaluated in wild type (WT) or genetically modified rodents suffering from collagen antibody-induced arthritis (CAIA). To address this, we analyzed nesting behavior in WT mice, calcitonin gene-related peptide alpha-deficient (αCGRP-/-) mice, and calcitonin receptor-deficient (Calcr-/-) mice suffering from experimental RA compared to healthy control (CTRL) groups of the same genotypes. CAIA was induced in 10-12-week-old male mice, and clinical parameters (body weight, grip strength, clinical arthritis score, ankle size) as well as nesting behavior were assessed over 10 or 48 days. A slight positive association between the nest score and body weight and grip strength was found for animals suffering from CAIA. For the clinical arthritis score and ankle size, no significant associations were observed. Mixed model analyses confirmed these associations. This study demonstrates that clinical effects of RA, such as loss of body weight and grip strength, might negatively affect nesting behavior in mice. Assessing nesting behavior in mice with arthritis could be an additional, non-invasive and thus valuable health parameter in future experiments to monitor welfare and discomfort in mice. During severe disease stages, pre-formed nest-building material may be provided to animals suffering from arthritis.

Tramadol/paracetamol treatment attenuates the development of collagen antibody-induced arthritis and interferes with prednisolone treatment in mice

The collagen antibody-induced arthritis (CAIA) model is highly effective in inducing arthritis, making it an attractive model for screening therapeutic compounds such as glucocorticoids (GCs). The severity of discomfort in this model makes it desirable to administer analgesics, but it is a prerequisite that these do not interfere with the model or tested therapeutics. In the present study, we studied the effect of 1 mg/mL tramadol and 3.5 mg/mL paracetamol (TP) on CAIA in male BALB/cAnNCrl mice and the possible interference of TP analgesia with the activity of the GC drug prednisolone (Pred). Our results showed that TP abolished the Pred-induced amelioration of CAIA, as well as several other Pred-induced effects, such as the reduction in thymus weight and the increase in insulin level. This most likely results from the effects of TP on the hepatic metabolism of this drug, since it strongly increased the Cyp3a11 expression in the liver. Altogether, we conclude that TP analgesia is not suitable for the CAIA model in male BALB/cAnNCrl mice, in particular when evaluating the effects of GCs such as Pred.

Global, but not chondrocyte-specific, MT1-MMP deficiency in adult mice causes inflammatory arthritis

Membrane-type I metalloproteinase (MT1-MMP/MMP14) plays a key role in various pathophysiological processes, indicating an unaddressed need for a targeted therapeutic approach. However, mice genetically deficient in Mmp14 show severe defects in development and growth. To investigate the possibility of MT1-MMP inhibition as a safe treatment in adults, we generated global Mmp14 tamoxifen-induced conditional knockout (Mmp14kd) mice and found that MT1-MMP deficiency in adult mice resulted in severe inflammatory arthritis. Mmp14kd mice started to show noticeably swollen joints two weeks after tamoxifen administration, which progressed rapidly. Mmp14kd mice reached a humane endpoint 6 to 8 weeks after tamoxifen administration due to severe arthritis. Plasma TNF-α levels were also significantly increased in Mmp14kd mice. Detailed analysis revealed chondrocyte hypertrophy, synovial fibrosis, and subchondral bone remodeling in the joints of Mmp14kd mice. However, global conditional knockout of MT1-MMP in adult mice did not affect body weight, blood glucose, or plasma cholesterol and triglyceride levels. Furthermore, we observed substantial expression of MT1-MMP in the articular cartilage of patients with osteoarthritis. We then developed chondrocyte-specific Mmp14 tamoxifen-induced conditional knockout (Mmp14chkd) mice. Chondrocyte MT1-MMP deficiency in adult mice also caused apparent chondrocyte hypertrophy. However, Mmp14chkd mice did not exhibit synovial hyperplasia or noticeable arthritis, suggesting that chondrocyte MT1-MMP is not solely responsible for the onset of severe arthritis observed in Mmp14kd mice. Our findings also suggest that highly cell-type specific inhibition of MT1-MMP is required for its potential therapeutic use.

Protective effect of fustin against adjuvant-induced arthritis through the restoration of proinflammatory response and oxidative stress

Rheumatoid arthritis causes irreparable damage to joints. The present research sought to check fustin's anti-arthritic efficacy against the complete Freund's adjuvant-induced arthritis paradigm in animals by altering the inflammatory response. In the rats, complete Freund's adjuvant was used to trigger arthritis and they received fustin at 50 and 100 mg/kg for 21 days. At regular intervals, the hind paw volume and arthritic score were assessed. After the trial period, hematological, antioxidant, pro-inflammatory cytokines, and other biochemical parameters were estimated. Fustin-treated rats showed the down-regulation of hind paw volume, arthritic score, and altered hematological parameters (TLC, DLC (neutrophil, lymphocyte, monocyte, eosinophil, basophil)). Furthermore, fustin significantly mitigates proinflammatory cytokine (reduced interleukin, tumor necrosis factor-a (TNF-α), IL-6, IL-1β), oxidative stress (attenuated malondialdehyde (MDA), catalase (CAT), glutathione (GSH), superoxide dismutase (SOD)), attenuated production of prostaglandin E2 and myeloperoxidase (MPO) and improved nuclear factor erythroid 2-related factor (Nrf2) action. Fustin led to the benefit in arthritis-prone animals elicited by complete Freund's adjuvant via pro-inflammatory cytokine.

Determining the preferred liquid reward in adult C57BL/6 mice

Using food rewards to motivate mice is commonplace in behavioural research. Using a reward which is highly desirable is of benefit, as it can reduce the need to food restrict animals and can encourage higher levels of consumption, allowing for changes in levels of consumption following an intervention to be easily determined. Here, we aimed to determine the preferred milk reward for adult male C57Bl/6 mice. Thirty male C57Bl/6 mice were provided with soya milk, chocolate milk, almond milk or water for a four-hour period in a cross-over design. When planning studies that involve the use of a palatable liquid reward, soya milk is the preferred option for adult male C57BL/6 mice. Providing a liquid reward of high value will give increased levels of consumption, with little or no food restriction required.

Alcohol extracts from Anemone flaccida Fr. Schmidt treat rheumatoid arthritis via inhibition of synovial hyperplasia and angiogenesis

Anemone flaccida Fr. Schmidt, a Traditional Chinese Medicine, has been used in the treatment of rheumatoid arthritis (RA) for numerous years. However, the specific mechanisms remain to be elucidated. Thus, the present study aimed to investigate the main chemical constituents and potential mechanisms of Anemone flaccida Fr. Schmidt. The ethanol extract obtained from Anemone flaccida Fr. Schmidt (EAF) was analyzed using mass spectrometry to determine the main components and the therapeutic effects of EAF on RA were verified using a collagen‑induced arthritis (CIA) rat model. Results of the present study demonstrated that synovial hyperplasia and pannus of the model rats were significantly improved following EAF treatment. Moreover, the protein expression levels of VEGF and CD31‑labeled neovascularization were significantly reduced in the synovium of CIA rats following treatment with EAF, compared with those of the untreated model group. Subsequently, in vitro experiments were carried out to verify the impact of EAF on synovial proliferation and angiogenesis. Results of the western blot analysis revealed that EAF inhibited the PI3K signaling pathway in endothelial cells, which is associated with anti‑angiogenesis. In conclusion, results of the present study demonstrated the therapeutic effects of Anemone flaccida Fr. Schmidt on RA and preliminarily revealed the mechanisms of this drug in the treatment of RA.

In Vivo Longitudinal Monitoring of Disease Progression in Inflammatory Arthritis Animal Models Using Raman Spectroscopy

Current techniques for monitoring disease progression and testing drug efficacy in animal models of inflammatory arthritis are either destructive, time-consuming, subjective, or require ionizing radiation. To accommodate this, we have developed a non-invasive and label-free optical system based on Raman spectroscopy for monitoring tissue alterations in rodent models of arthritis at the biomolecular level. To test different sampling geometries, the system was designed to collect both transmission and reflection mode spectra. Mice with collagen antibody-induced arthritis and controls were subject to in vivo Raman spectroscopy at the tibiotarsal joint every 3 days for 14 days. Raman-derived measures of bone content correlated well with micro-computed tomography bone mineral densities. This allowed for time-resolved quantitation of bone densities, which indicated gradual bone erosion in mice with arthritis. Inflammatory pannus formation, bone erosion, and bone marrow inflammation were confirmed by histological analysis. In addition, using library-based spectral decomposition, we quantified the progression of bone and soft tissue components. In general, the tissue components followed significantly different tendencies in mice developing arthritis compared to the control group in line with the histological analysis. In total, this demonstrates Raman spectroscopy as a versatile technique for monitoring alterations to both mineralized and soft tissues simultaneously in rodent models of musculoskeletal disorders. Furthermore, the technique presented herein allows for objective repeated within-animal measurements potentially refining and reducing the use of animals in research while improving the development of novel antiarthritic therapeutics.

Effects of Multimodal Therapy, Blinding, and Multi-laboratory Protocol Conduct on the Robustness of the Rat Model of Adjuvant Induced Arthritis

BACKGROUND/AIM

The aim of this study was to investigate the effects of multimodal therapy comprising buprenorphine (BUP) and indomethacin (IND) on key translational parameters in the rat adjuvant induced arthritis (AIA) model. Furthermore, we investigated the difference between visual assessment scores and histology scores generated by blinded and non-blinded assessors and the robustness and generalizability of results by conducting a multi-laboratory study.

MATERIALS AND METHODS

The experiment was terminated on day 26 after 11 days (days 15-25) of voluntarily ingested buprenorphine and 7 days of gavage delivered indomethacin treatment (days 19-25). The treatment effects were assessed on the last day of the study, relying on body weight assessment, serum concentrations of α1- acid glycoprotein, and assessment of affected hind paws swelling, in-life and post mortem.

RESULTS

Across two laboratories, the combined analgesic treatments had minimal effects on the measured model parameters indicating that multimodal treatment did not affect the translatability of the model. We found an improvement in clinical scores (a negative change in scores) in nearly all medicated animals when scored informed, whereas it was essentially 50:50 for the blinded scorings and no difference between the blinded and informed histological scoring.

CONCLUSION

The present results support the use of more effective analgesic treatment regimens and the good practice recommendations advocating blinding as a mandatory practice in conduct of preclinical in vivo efficacy studies. In spite of minor differences between results obtained at the two sites, there was good agreement between them indicating robustness of the AIA model.

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.

Effects of dexamethasone and acetylsalicylic acid on inflammation caused by complete Freund’s adjuvant in the naked mole rat (Heterocephalus glaber)

The naked mole rat (NMR) is a fossorial rodent that has been observed to have a unique nociceptive system in comparison to others. In this study, we explored on characterization of chronic inflammation in the NMR using Complete Freund's adjuvant (CFA) and investigated the effects of dexamethasone and acetylsalicylic acid on the resulting inflammation. The NMRs were injected with 0.1 ml of CFA subcutaneously in the right hind paw, and an equivalent volume of normal saline was injected to the control group. Swelling of the injected right hind limb was observed within 24 h of injection, which involved the tibiotarsal joint, palmar surface and the digits of the injected paw. Swelling persisted for 6 weeks of experimentation and peaked between day 14 and 21. The resulting inflammation affected the mobility, stance and joint rigidity of CFA treated NMRs in comparison to the control group. Treatment of the chronic phase of the inflammation from the 11^th day with dexamethasone and acetylsalicylic acid showed no statistical significance in paw circumference compared to the control group, other than on a few, negligible occasions. The present data showed that CFA was able to induce chronic inflammation in the NMR, and the NMR could thus be established as a model for chronic inflammation. There is, however, need for more sensitive parameters to evaluate the effects of anti-inflammatory drugs.

Effects of different doses of complete Freund's adjuvant on nociceptive behaviour and inflammatory parameters in polyarthritic rat model mimicking rheumatoid arthritis

Complete Freund's adjuvant (CFA) has been used to develop the arthritic or inflammatory condition in the animal, but there is a lack of information concerning high CFA doses on nociceptive behaviour and inflammatory parameters. This study aimed to compare the effects of different high doses of CFA in rat to closely mimic nociceptive and inflammatory parameters of rheumatoid arthritis (RA) in humans. Twenty-four male Sprague-Dawley rats were randomly divided into four groups (n = 6): Control (C), CFA-induced polyarthritic groups at 5.0 mg/mL (CFA 5.0), 7.5 mg/mL (CFA 7.5) and 10.0mg/mL (CFA 10.0). The rats' right hindpaw was inoculated with CFA intradermally and developed into a polyarthritic state within 20 days. Nociceptive behavioural assessments, including von Frey and hot plate tests and spontaneous activities, were conducted on day 0, 7, 15 and 20. Bilateral ankle joints diameter and circumference, full blood count, joints and paw histological examinations were also conducted throughout the study period. Based on the results, CFA 5.0 and CFA 7.5 groups showed a significant increase in spontaneous activities and development of thermal hyperalgesia but no change in body weight and food intake, no development of tactile allodynia and haematological indices, and no significant morphological changes of joints histology. Meanwhile, CFA 10.0 group demonstrated significant and constant changes in all nociceptive and inflammatory parameters investigated. In conclusion, CFA at the dose of 10mg/mL has the most potential and reliable dosage to develop polyarthritis in a rat model to mimic RA condition in humans.

A fructosylated peptide derived from a collagen II T cell epitope for long-term treatment of arthritis (FIA-CIA) in mice

Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease which affects primarily the joints. Peptides of several proteins have shown an effect in some experimental animal models of RA. We investigated arthritis development in male DBA/1 mice which were injected with bovine collagen II (bCII) and human fibrinogen (hFib) on days 0 and 21, leading to stable and reproducible disease induction in 100% of immunized mice (FIA-CIA). In a second study, two bCII-derived peptides were given three times in the course of 6 weeks after FIA-CIA induction to test for impact on arthritis. Mice were scored weekly for arthritis and anti-citrullinated peptide antibodies (ACPAs) were determined in the sera taken on days 0, 14, 35, 56 and 84. Histology of the hind paws was performed at the end of the experiment. Intravenous administration of peptide 90578, a novel fructosylated peptide derived from the immunodominant T cell epitope of bCII, at a dosage of 1 mg/kg resulted in significant beneficial effects on clinical outcome parameters and on the arthritis histology scores which was sustained over 12 weeks. Survival tended to be improved in peptide 90578-treated mice. Intravenous administration of pure soluble peptide 90578 without adjuvants is a promising approach to treat RA, with treatment starting at a time when ACPAs are already present. The results complement existing data on peptide "vaccination" of healthy animals, or on treatment using recombinant peptide expressing virus or complex biological compounds.

Modulation of inflammation by anti-TNF α mAb-dendrimer nanoparticles loaded in tyramine-modified gellan gum hydrogels in a cartilage-on-a-chip model

Rheumatoid arthritis (RA) is an autoimmune and chronic inflammatory disease characterized by joint inflammation. Since the inflammatory condition plays an important role in the disease process, it is important to develop and test new therapeutic approaches that specifically target and treat joint inflammation. In this study, a human 3D inflammatory cartilage-on-a-chip model was established to test the therapeutic efficacy of anti-TNFα mAb-CS/PAMAM dendrimer NPs loaded-Tyramine-Gellan Gum in the treatment of inflammation. The results showed that the proposed therapeutic approach applied to the human monocyte cell line (THP-1) and human chondrogenic primary cells (hCH) cell-based inflammation system revealed an anti-inflammatory capacity that increased over 14 days. It was also possible to observe that Coll type II was highly expressed by inflamed hCH upon the culture with anti-TNF α mAb-CS/PAMAM dendrimer NPs, indicating that the hCH cells were able maintain their biological function. The developed preclinical model allowed us to provide more robust data on the potential therapeutic effect of anti-TNF α mAb-CS/PAMAM dendrimer NPs loaded-Ty-GG hydrogel in a physiologically relevant model.

A 8-mer Peptide of PGLYRP1/Tag7 Innate Immunity Protein Binds to TNFR1 Receptor and Inhibits TNFα-Induced Cytotoxic Effect and Inflammation

Search for novel regulatory protein fragments with potential functional roles is required both for understanding the immune response mechanisms and the development of targeted immunotherapy. Earlier we demonstrated that the PGLYRP1/Tag7 innate immunity protein can be regarded as an inhibitor of TNFα cytotoxic activity via the interaction with its TNF receptor 1 (TNFR1). A C-terminal peptide fragment 17.1 of the molecule is responsible for this function. In this study we have identified a minimal 8-mer region of this peptide (hereinafter – 17.1A) capable to bind to TNFR1. As a result of such interaction, the cytotoxic signals induced by this receptor are blocked. Also, this peptide demonstrates an anti-inflammatory activity in vivo in the complete Freund’s adjuvant (CFA)-induced arthritis model in laboratory mice. Peptide 17.1A is capable to reduce periarticular inflammation, inhibit the development of synovitis and exhibit a protective effect on cartilage and bone tissues. This peptide can turn out to be a promising medicinal agent for autoimmune arthritis and other diseases.

Non-target metabolomic analysis reveals the therapeutic effect of Saposhnikovia divaricata decoction on collagen-induced arthritis rats

ETHNOPHARMACOLOGICAL RELEVANCE

Saposhnikovia divaricata (SD), a Chinese crude drug, has long been recognized for therapeutic effect to rheumatoid arthritis (RA). At present, the mechanisms of SD treatment in RA have not been fully understood especially on the perspective of metabolomics.

AIM OF THE STUDY

To study the pharmacodynamic effects of Saposhnikovia divaricata decoction on CIA rats, and explore the therapeutic mechanism by metabolomics methods.

MATERIALS AND METHODS

Wistar rats were randomly divided into normal group, CIA model group, dexamethasone group and SD decoction groups (10 g crude drug/kg, 5 g crude drug/kg and 2.5 g crude drug/kg of SDD). Body weight, arthritis scores, serum cytokine levels and histopathological parameters of rats were assessed. A metabolomics method based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOFMS) was established to collect the metabolic profiles of rats and explore the metabolic changes that occurred after SDD treatment.

RESULTS

SDD showed its protective effect on the affected joints, especially in the middle dosage group of SDD. Eighteen and 13 potential biomarkers for the SDD treatment of CIA rats were identified in the plasma and urine, respectively. SDD could regulate the disturbed metabolic pathways including tryptophan metabolism, glycerophospholipid catabolism, primary bile acid biosynthesis and fatty acid metabolism.

CONCLUSIONS

In summary, SDD treatment could effectively alleviate symptoms of RA and regulate metabolic disorders in CIA rats.

Strontium ranelate-laden near-infrared photothermal-inspired methylcellulose hydrogel for arthritis treatment

Rheumatoid arthritis (RA) is of foremost concern among long-term autoimmune disorders, as it leads to inflammation, exudates, chondral degeneration, and painful joints. Because RA severity often fluctuates over time, a local drug delivery method that titrates release of therapeutics to arthritis bioactivity should represent a promising paradigm of RA therapy. Given the local nature of RA chronic illnesses, polysaccharide-drug delivering systems have the promise to augment therapeutic outcomes by offering controlled release of bioactive materials, diminishing the required frequency of administration, and preserving therapeutic levels in affected pathological regions. Herein, an intra-articular photothermal-laden injectable methylcellulose (MC) polymeric hydrogel carrier incorporating strontium ranelate (SrR) and sodium chloride was investigated to resolve these issues. Physicochemical and cellular characteristics of the MC carrier system were thoroughly evaluated. The slow release of SrR, enhancement of the material mechanical strength, and the potential of the non-invasive near-infrared photothermal gel to improve blood circulation and suppress inflammation in a mini-surgical model of RA were examined. Biocompatibility and suppression of intracellular ROS-induced inflammation were observed. This multifunctional photothermal MC hydrogel carrier is anticipated to be an alternative approach for future orthopedic disease treatment.

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.

Essential Oils of Foeniculum vulgare subsp. piperitum and Their in Vitro Anti-Arthritic Potential

Wild Foeniculum vulgare subsp. piperitum (C.Presl) Bég. flowers, fruits and leaves were extracted with steam distillation and obtained essential oils (EOs) were characterized using GC/MS. The study was designed to verify the potential effectiveness of fennel EOs in the treatment of inflammation and arthritis. Since tissue proteins denaturation is a major cause of arthritic diseases, fennel EOs and their main constituents were evaluated for their ability to inhibit the heat-induced proteins degradation using bovine serum albumin as a protein model. Moreover, the in vitro inhibitory effects of the three EOs on the pro-inflammatory mediator nitric oxide (NO) production were verified in LPS-stimulated RAW 264.7 cells. Estragole (28.81-33.40 %), anethole (24.16-27.40 %), fenchone (9.76-18.48 %), α-phellandrene (1.63-8.37 %) and limonene (5.54-6.05 %) were the major constituents. All the EOs showed a concentration-dependent biological activity, being the flower EO the most effective in inhibiting NO production (IC₅₀ =232.2±11.3 μg/mL). The leaf EO showed a very good bovine serum albumin (BSA) anti-denaturation activity (IC₅₀ =95.9±2.4 μg/mL). Moreover, four components were proved to be effective in protecting protein from heat-induced degradation, being α-phellandrene the most active compound (IC₅₀ =73.2±1.9 μg/mL).

Dual-Acting Peripherally Restricted Delta/Kappa Opioid (CAV1001) Produces Antinociception in Animal Models of Sub-Acute and Chronic Pain

Background

The development of highly efficacious alternatives to mu-opioid analgesics represents an urgent unmet medical and public health need. In the presence of inflammation both delta- and kappa-opioid agonists, acting on peripheral sensory neurons, mediate analgesia. The dual-acting, peripherally restricted kappa/delta-opioid agonist, CAV1001, was tested in four rodent pain models.

Methods

Experiment 1 – Formalin testing in mice. Three doses (1–10 mg/kg) of CAV1001 or ICI204448 at 30 minutes were tested after formalin injection. Spontaneous nocifensive responses were video recorded. Experiment 2 – Complete Freund’s Adjuvant (CFA)-induced arthritis. CFA was injected into the ankle joint of rats. Joint compression thresholds (JCT) were measured. CAV1001 was compared to celecoxib. Experiment 3 – Spinal nerve ligation (SNL) in rats. Paw compression thresholds (PCT) were measured. CAV1001 was compared to gabapentin. Experiment 4 – MMRT-1 bone cancer implantation into the rat tibia. Weight-bearing was assessed. CAV1001 was compared to morphine.

Results

In Phase 2 of the formalin model, CAV1001 (1 mg/kg) significantly reduced pain behaviors to a degree comparable to the peripherally restricted kappa-opioid agonist, ICI204448 (10 mg/kg). CAV1001 (10 mg/kg) effectively eliminated pain behaviors associated with phase 2. In the CFA-induced arthritis model, a significant increase in JCTs, similar to the comparator celecoxib, was observed with CAV1001 at 1 mg/kg at 2 hours; CAV1001 (10 mg/kg) was effective at 1 hour. In the SNL model, both the comparator gabapentin and CAV1001 (5 mg/kg) significantly reduced PCT at 2 hours, but at 4 hours, the CAV1001 thresholds improved to baseline. CAV1001 10 mg/kg significantly improved weight bearing at 4-hour post-dosing compared to baseline following MMRT-1 implantation.

Conclusion

CAV1001 demonstrated efficacy in several different preclinical pain models. Time- and dose-dependent differences in the efficacy of CAV1001 amongst these rodent pain models parallel the degree of underlying inflammation.

Aliskiren, tadalafil, and cinnamaldehyde alleviate joint destruction biomarkers; MMP-3 and RANKL; in complete Freund's adjuvant arthritis model: Downregulation of IL-6/JAK2/STAT3 signaling pathway

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease, which is accompanied by progressive joint damage and disability. The intolerability of conventional antirheumatic drugs by some patients necessitates the search for effective antirheumatic agents having better tolerability. In the current work, we aimed to investigate the efficacy of cinnamaldehyde, tadalafil, and aliskiren as potential antirheumatic candidates and to explore their modulatory effects on joint destruction, inflammatory response, and intracellular signaling. Arthritis was induced in female Wistar rats by complete Freund's adjuvant (CFA) 0.4 ml s.c. on days 1, 4, and 7. Treated groups received their respective drugs, starting from day 13, daily for 3 weeks. Methotrexate and prednisolone were the standard antirheumatic drugs, while cinnamaldehyde, tadalafil, and aliskiren were the test agents. Treatment with cinnamaldehyde, tadalafil, or aliskiren reduced serum levels of rheumatoid factor, and pro-inflammatory cytokines; tumor necrosis factor-alpha and interleukin-6 (IL-6), along with elevated level of IL-10 which is an anti-inflammatory cytokine. Besides, cartilage and bone destruction biomarkers; matrix metalloproteinase-3 (MMP-3) and receptor activator of nuclear factor-kappa B ligand (RANKL); were significantly reduced after treatment with the test agents, which was further confirmed by histopathological investigation. The elevated protein expressions of phosphorylated-Janus kinase 2 (p-JAK2), phosphorylated-signal transducer and activator of transcription 3 (p-STAT3), and inducible nitric oxide synthase (iNOS) in articular tissue were markedly attenuated after treatment with cinnamaldehyde, tadalafil, or aliskiren, while that of endothelial nitric oxide synthase (eNOS) was greatly enhanced. In addition, oxidative stress and inflammatory markers such as malondialdehyde, nitric oxide, and myeloperoxidase were reduced in joint tissue after treatment with the test agents, while glutathione content was elevated. Furthermore, the renin inhibitor aliskiren produced effects close to those of the normal and methotrexate, the gold standard antirheumatic drug, in most of the measured parameters.

Collectively, these findings led to the assumption that the downregulation of IL-6/JAK2/STAT3 signaling by cinnamaldehyde, tadalafil, and aliskiren could alleviate joint destruction by MMP-3 and RANKL, reduce iNOS, and enhance eNOS expressions. Moreover, aliskiren could be a promising therapeutic agent for RA, because of its ability to normalize most of the measured parameters after CFA-induced arthritis.

Sex-Based Differences in Monocytic Lineage Cells Contribute to More Severe Collagen-Induced Arthritis in Female Rats Compared with Male Rats

Monocytes' plasticity has an important role in the development of rheumatoid arthritis (RA), an autoimmune disease exhibiting greater prevalence in women. Contribution of this phenomenon to sex bias in RA severity was investigated in rat collagen-induced arthritis (CIA) model of RA. The greater severity of CIA in females (exhibiting signs of bone resorption) was accompanied by the higher blood level of advanced oxidation protein products and a more pro-oxidant profile. Consistently, in females, the greater density of giant multinuclear cells (monocytes/macrophages and osteoclasts) in inflamed joint tissue was found. This correlated with the higher frequencies of CCR2- and CX3CR1- expressing cells (precursors of inflammatory monocytes/macrophages and osteoclasts) among CD11b+ splenocytes. This in conjunction with the enhanced migratory capacity of CD11b+ monocytic cells in females compared with males could be linked with the higher frequencies of CCR2+CX3CR1-CD43^lowCD11b+ and CCR2-CX3CR1+CD43^hiCD11b+ cells (corresponding to "classical" and "non-classical" monocytes, respectively) and the greater density of CD68+ cells (monocytes/macrophages and osteoclast precursors/osteoclasts) in blood and inflamed paws from female rats, respectively. Consistently, the higher levels of GM-CSF, TNF-α and IL-6, IL-1β (driving Th17 cell differentiation), and IL-17 followed by the lower level of IL-10 were measured in inflamed paw cultures from female compared with male rats. To the greater IL-17 production (associated with enhanced monocyte immigration and differentiation into osteoclasts) most likely contributed augmented Th17 cell generation in the lymph nodes draining arthritic joints from female compared with male rats. Overall, the study suggests the sex-specific contribution of monocytic lineage cells to CIA, and possibly RA development.

Body weight algorithm predicts humane endpoint in an intracranial rat glioma model

Humane endpoint determination is fundamental in animal experimentation. Despite commonly accepted endpoint criteria for intracranial tumour models (20% body weight loss and deteriorated clinical score) some animals still die before being euthanized in current research. We here systematically evaluated other measures as surrogates for a more reliable humane endpoint determination. Adult male BDIX rats (n = 119) with intracranial glioma formation after BT4Ca cell-injection were used. Clinical score and body weight were assessed daily. One subgroup (n = 14) was assessed daily for species-specific (nesting, burrowing), motor (distance, coordination) and social behaviour. Another subgroup (n = 8) was implanted with a telemetric device for monitoring heart rate (variability), temperature and activity. Body weight and clinical score of all other rats were used for training (n = 34) and validation (n = 63) of an elaborate body weight course analysis algorithm for endpoint detection. BT4Ca cell-injection reliably induced fast-growing tumours. No behavioural or physiological parameter detected deteriorations of the clinical state earlier or more reliable than clinical scoring by experienced observers. However, the body weight course analysis algorithm predicted endpoints in 97% of animals without confounding observer-dependent factors. Clinical scoring together with the novel algorithm enables highly reliable and observer-independent endpoint determination in a rodent intracranial tumour model.

Protective effect of a new hyaluronic acid -carnosine conjugate on the modulation of the inflammatory response in mice subjected to collagen-induced arthritis

Several studies demonstrated the pharmacological actions of carnosine as well as hyaluronic acid (HA) during joint inflammation. In that regard, the aim of this study was to investigate the protective effect of a new HA -Carnosine conjugate (FidHycarn) on the modulation of the inflammatory response in mice subjected to collagen-induced arthritis (CIA). CIA was induced by two intradermal injections of 100 μl of an emulsion of collagen (CII) and complete Freund's adjuvant (CFA) at the base of the tail on day 0 and 21. At 35 day post CIA induction, the animals were sacrificed. CII injection caused erythema and edema in the hind paws, histological alterations with erosion of the joint cartilage as well as behavioral changes. Oral treatment with FidHycarn starting at the onset of arthritis (day 25) ameliorated the clinical signs, improved behavioral deficits as well as decreased histological and radiographic alterations. The degree of oxidative damage evaluated by inducible nitric oxide synthase (iNOS), nitrotyrosine, poly-ADP-ribose (PAR) expressions and malondialdehyde (MDA) levels, was also significantly reduced in Carnosine+HA association and FidHycarn treated mice. Moreover, the levels of proinflammatory cytokines and chemokines and cyclo-oxygenase COX-2 enzyme were also more significantly reduced by Carnosine+HA and FidHycarn compared to carnosine alone. However, interestingly, in some cases, the effects of FidHycarn were more important than Carnosine+HA association and not statistically different to methotrexate (MTX) used as positive control. Thus, the conjugation of Carnosine with HA (FidHycarn) could represent an interesting therapeutic strategy to combat arthritis disorders.

A Review of the Effects of Pain and Analgesia on Immune System Function and Inflammation: Relevance for Preclinical Studies

One of the most significant challenges facing investigators, laboratory animal veterinarians, and IACUCs, is how to balance appropriate analgesic use, animal welfare, and analgesic impact on experimental results. This is particularly true for in vivo studies on immune system function and inflammatory disease. Often times the effects of analgesic drugs on a particular immune function or model are incomplete or don't exist. Further complicating the picture is evidence of the very tight integration and bidirectional functionality between the immune system and branches of the nervous system involved in nociception and pain. These relationships have advanced the concept of understanding pain as a protective neuroimmune function and recognizing pathologic pain as a neuroimmune disease. This review strives to summarize extant literature on the effects of pain and analgesia on immune system function and inflammation in the context of preclinical in vivo studies. The authors hope this work will help to guide selection of analgesics for preclinical studies of inflammatory disease and immune system function.

The Systemic Immune Response to Collagen-Induced Arthritis and the Impact of Bone Injury in Inflammatory Conditions

Rheumatoid arthritis (RA) is a systemic disease that affects the osteoarticular system, associated with bone fragility and increased risk of fractures. Herein, we aimed to characterize the systemic impact of the rat collagen-induced arthritis (CIA) model and explore its combination with femoral bone defect (FD). The impact of CIA on endogenous mesenchymal stem/stromal cells (MSC) was also investigated. CIA induction led to enlarged, more proliferative, spleen and draining lymph nodes, with altered proportion of lymphoid populations. Upon FD, CIA animals increased the systemic myeloid cell proportions, and their expression of co-stimulatory molecules CD40 and CD86. Screening plasma cytokine/chemokine levels showed increased tumor necrosis factor-α (TNF-α), Interleukin (IL)-17, IL-4, IL-5, and IL-12 in CIA, and IL-2 and IL-6 increased in CIA and CIA+FD, while Fractalkine and Leptin were decreased in both groups. CIA-derived MSC showed lower metabolic activity and proliferation, and significantly increased osteogenic and chondrogenic differentiation markers. Exposure of control-MSC to TNF-α partially mimicked the CIA-MSC phenotype in vitro. In conclusion, inflammatory conditions of CIA led to alterations in systemic immune cell proportions, circulating mediators, and in endogenous MSC. CIA animals respond to FD, and the combined model can be used to study the mechanisms of bone repair in inflammatory conditions.

Evaluation In Vivo and In Vitro of the Antioxidant, Antinociceptive, and Anti-Inflammatory Activities of Biflavonoids From Ouratea hexasperma and O. ferruginea

Ouratea species are used for the treatment of inflammation-related diseases such as rheumatism and arthritic disorders. The Ouratea genus is a rich source of flavonoids and bioflavonoids and for this reason we evaluated the effects of the biflavonoid fractions from the leaves of O. hexasperma (OHME) and O. ferruginea (OFME) in the in vivo model of complete Freund’s adjuvant (CFA)-induced arthritis and in the in vitro model of oxidative stress and cellular viability. The CFA-induced arthritis model in rats was followed by paw volume, articular incapacitation and Randall-selitto models, as well as quantification of cytokines and serum C-terminal telopeptide of type I collagen levels. OHME and OFME demonstrated antinociceptive and anti-inflammatory activities, as well as improvement in articular incapacity and reduction in levels of interleukin 1β (IL-1β), IL-6, tumor necrosis factor α, and type 1 collagen, and increased cell viability. No adverse effects were observed. The results suggest that OHME and OFME can reduce inflammation and bone resorption besides their antioxidant action.

Redox Status and Muscle Pathology in Rheumatoid Arthritis: Insights from Various Rat Hindlimb Muscles

Due to atrophy, muscle weakness is a common occurrence in rheumatoid arthritis (RA). The majority of human studies are conducted on the vastus lateralis muscle—a muscle with mixed fiber type—but little comparative data between multiple muscles in either rodent or human models are available. The current study therefore assessed both muscle ultrastructure and selected redox indicators across various muscles in a model of collagen-induced rheumatoid arthritis in female Sprague-Dawley rats. Only three muscles, the gastrocnemius, extensor digitorum longus (EDL), and soleus, had lower muscle mass (38%, 27%, and 25% loss of muscle mass, respectively; all at least P < 0.01), while the vastus lateralis muscle mass was increased by 35% (P < 0.01) in RA animals when compared to non-RA controls. However, all four muscles exhibited signs of deterioration indicative of rheumatoid cachexia. Cross-sectional area was similarly reduced in gastrocnemius, EDL, and soleus (60%, 58%, and 64%, respectively; all P < 0.001), but vastus lateralis (22% smaller, P < 0.05) was less affected, while collagen deposition was significantly increased in muscles. This pathology was associated with significant increases in tissue levels of reactive oxygen species (ROS) in all muscles except the vastus lateralis, while only the gastrocnemius had significantly increased levels of lipid peroxidation (TBARS) and antioxidant activity (FRAP). Current data illustrates the differential responses of different skeletal muscles of the hindlimb to a chronic inflammatory challenge both in terms of redox changes and resistance to cachexia.

The Application of Humane Endpoints and Humane Killing Methods in Animal Research Proposals: A Retrospective Review

Refinement refers to the use of methods that help to minimise animal suffering in the laboratory. Research in this area has increased significantly over the past two decades. However, the extent to which refinements are applied in practice is uncertain. To provide an indication of the implementation and awareness of refinements, we reviewed the experimental techniques for 684 surgical interventions described in 506 animal research applications sent to the German competent authorities for approval in 2010. In this paper, we describe and discuss the appropriateness of the proposed humane endpoints and killing methods. We found that, when the investigators included humane endpoints in their application, these were often lacking in detail and/or were to be implemented at a late stage of suffering. In addition, the choice of method to kill the animals could be improved in the majority of the applications. We provide recommendations for future improvements, based on the recent literature. To ensure scientific rigour, avoid needless animal suffering and enable an accurate harm–benefit analysis, animal researchers have to be knowledgeable about refinement methods and apply them effectively. To assess compliance and ensure that only those studies in which potential benefits outweigh the harms are carried out, reviews such as ours — as well as retrospective assessments of actual harms and benefits — should be conducted widely and regularly, and the findings should be published.

Identifying and Implementing Endpoints for Geriatric Mice

The types of changes in physical appearance and behavior that occur in elderly people similarly develop in elderly animals. Signs and symptoms that might cause concern in younger people or mice may be normal in their elderly but generally healthy counterparts. Although numerous scoring methods have been developed to assess rodent health, these systems were often designed for young adults used in specific types of research, such as cancer or neurologic studies, and therefore may be suboptimal for assessing aging rodents. Approaches known as frailty assessments provide a global evaluation of the health of aged mice, rats, and people, and mouse frailty scores correlate well with the likelihood of death. Complementing frailty assessment, prediction of imminent death in aged mice can often be accomplished by focusing on 2 objective parameters-body weight and temperature. Before they die, many (but not all) mice develop marked reductions in body weight and temperature, thus providing signs that close monitoring, intervention, or preemptive euthanasia may be necessary. Timely preemptive euthanasia allows antemortem collection of data and samples that would be lost if spontaneous death occurred; preemptive euthanasia also limits terminal suffering. These approaches to monitoring declining health and predicting death in elderly research mice can aid in establishing and implementing timely interventions that both benefit the research and reduce antemortem suffering.

Therapeutic effects of polysaccharides from Anoectochilus roxburghii on type II collagen-induced arthritis in rats

Anoectochilus roxburghii, a famous Chinese herbal medicine, has been commonly used for the treatment of liver disease, diabetes, and rheumatoid arthritis. Our study aimed to investigate the anti-rheumatoid arthritis effects of A. roxburghii polysaccharides (ARP), using the rat's model of type II collagen-induced arthritis (CIA). ARP was prepared by alcohol sedimentation and structurally characterized based on combined chemical, chromatographic and spectroscopic methods. High Performance Size Exclusion Chromatography-Multiangle Laser Light Scattering-Refrative Index (HPSEC-MALLS-RI) analysis revealed that ARP includes two peaks, and the weight-average molecular weight (Mw) of the principal one was estimated as 5.90 kDa with a relative content of 98.2%. Pharmacological results exhibited that ARP significantly decreased the arthritis index and ameliorated the inflammatory cell infiltration and the synovial tissue destruction in CIA rats. Additionally, ARP possessed significant NO production inhibitory effects and antioxidant activity. Further anti-inflammatory mechanism investigations indicated that ARP significantly inhibited the activation of nuclear factor κB (NF-κB) pathway by suppressing the phosphorylation of IκB and p65, which subsequently down-regulated the mRNA expressions of IL-1β and IL-6 in LPS-stimulated RAW 264.7 cells. These findings suggested that ARP has great potential in the development of functional foods and dietary supplements for the treatment of rheumatoid arthritis.

In Vivo Models for Inflammatory Arthritis

In vivo mouse models of inflammatory arthritis are extensively used to investigate pathogenic mechanisms governing inflammation-driven joint damage. Two commonly utilized models include collagen-induced arthritis (CIA) and methylated bovine serum albumin (mBSA) antigen-induced arthritis (AIA). These offer unique advantages for modeling different aspects of human disease. CIA involves breach of immunological tolerance resulting in systemic autoantibody-driven arthritis, while AIA results in local resolving inflammatory flares and articular T cell-mediated damage. Despite limitations that apply to all animal models of human disease, CIA and AIA have been instrumental in identifying pathogenic mediators, immune cell subsets and stromal cell responses that determine disease onset, progression, and severity. Moreover, these models have enabled investigation of disease phases not easily studied in patients and have served as testing beds for novel biological therapies, including cytokine blockers and small molecule inhibitors of intracellular signaling that have revolutionized rheumatoid arthritis treatment.

In vivo anti-arthritic and anti-nociceptive effects of ethanol extract of Moringa oleifera leaves on complete Freund's adjuvant (CFA)-induced arthritis in rats

Background

The medicinal uses of plants are in many cases based exclusively on traditional knowledge without enough scientific evidences. Different parts of Moringa oleifera were traditionally used for the treatment of wide variety of ailments including arthritis and joints pain. The present study had been designed to evaluate the anti-arthritic and anti-nociceptive activities of ethanol extract of Moringa leaves, this being the most abundant plant part suitable for commercial mass production of botanical medicinal products.

Methods

Complete Freund's adjuvant (CFA)-induced arthritis in rats was used as disease model. CFA-induced inflammatory paw edema, body weight, arthritic index, X-ray radiography, hematological parameters, and walk track and locomotion analysis were all evaluated for the assessment of disease progression. In addition to that, anti-nociceptive activity was examined at different dose levels in both normal and arthritic-induced rats using Eddy's hot plate and tail flick thermal analgesia.

Results

The analysis of various arthritic assessment parameters used in this study revealed that Moringa extract has a considerable effect in preventing development or ameliorate arthritis disease severity. Moreover, the ethanol extract of Moringa leaves revealed significant anti-nociceptive activity at in both normal and CFA-induced arthritis rats in a dose-dependent manner.

Conclusion

Ethanol extract of Moringa leaves appears to be a really promising as analgesic and arthritis medication, but a larger and more detailed preclinical and clinical studies especially in human is highly recommended.

To Treat or Not to Treat: The Effects of Pain on Experimental Parameters

A common dilemma faced by all animal bioethics committees arises when exceptions are proposed to the use of analgesics in painful procedures. The committee and researcher must weigh the possible confounding effects of including additional drugs (analgesics) in their treatment regimen against the moral obligation to perform humane research. Often neglected in these considerations are the potential confounding effects of unrelieved pain and consistency with pain-relieving practices in human medicine. In this review, we summarize what is currently known regarding the molecular and physiologic effects of pain and analgesics in common animal models used across several therapeutic areas. This work is intended to help provide guidance and assurance that a comprehensive approach has been taken when contemplating how pain relief will be applied in animal research protocols.

Development of the Digital Arthritis Index, a Novel Metric to Measure Disease Parameters in a Rat Model of Rheumatoid Arthritis

Despite a broad spectrum of anti-arthritic drugs currently on the market, there is a constant demand to develop improved therapeutic agents. Efficient compound screening and rapid evaluation of treatment efficacy in animal models of rheumatoid arthritis (RA) can accelerate the development of clinical candidates. Compound screening by evaluation of disease phenotypes in animal models facilitates preclinical research by enhancing understanding of human pathophysiology; however, there is still a continuous need to improve methods for evaluating disease. Current clinical assessment methods are challenged by the subjective nature of scoring-based methods, time-consuming longitudinal experiments, and the requirement for better functional readouts with relevance to human disease. To address these needs, we developed a low-touch, digital platform for phenotyping preclinical rodent models of disease. As a proof-of-concept, we utilized the rat collagen-induced arthritis (CIA) model of RA and developed the Digital Arthritis Index (DAI), an objective and automated behavioral metric that does not require human-animal interaction during the measurement and calculation of disease parameters. The DAI detected the development of arthritis similar to standard in vivo methods, including ankle joint measurements and arthritis scores, as well as demonstrated a positive correlation to ankle joint histopathology. The DAI also determined responses to multiple standard-of-care (SOC) treatments and nine repurposed compounds predicted by the SMarTR^TM Engine to have varying degrees of impact on RA. The disease profiles generated by the DAI complemented those generated by standard methods. The DAI is a highly reproducible and automated approach that can be used in-conjunction with standard methods for detecting RA disease progression and conducting phenotypic drug screens.

Subchronic Infection of Porphyromonas gingivalis and Tannerella forsythia Stimulates an Immune Response but Not Arthritis in Experimental Murine Model

Studies have proposed that Porphyromonas gingivalis (Pg) and Tannerella forsythia (Tf) promote a nonspecific inflammatory response that could produce systemic disease. Oral inoculation of Pg and Tf on the immune and arthritis response was evaluated in BALB/C mice divided into four groups: (1) sham; (2) food contaminated with Pg/Tf; (3) complete Freund's adjuvant (CFA) + Pg/Tf; and (4) CFA alone. CFA was administered subcutaneously on days 1 and 14. The arthritis response was monitored for 21 days after day 14 of CFA administration. IL-1β and IL-6 were determined in serum. T cell activation was evaluated by CD25 in salivary lymph nodes or mouse spleen. Pad inflammation appeared by day 19 in the CFA group, but animals with bacteria inoculation presented a delay. A significant increase in IL-6 was found in Groups 3 and 4, but not with respect to IL-1β. We observed an increase in CD25 in cells derived from cervical nodes and in animals with bacteria inoculation and CFA. A local immune response was observed in mice inoculated with Pg and Tf (T cell activation); a systemic response was observed with CFA. Since pad inflammation was delayed by bacterial inoculation this suggests that local T cell activation could decrease pad inflammation.

Anti-inflammatory and Analgesic Activities of Topical Formulations of Pterocarpus Santalinus Powder in Rat Model of Chronic Inflammation

INTRODUCTION

The incidence of arthritis is quite high and there is a need for the search of natural products to halt the progression of disease or provide symptomatic relief without significant adverse effects.

AIM

This study aimed at evaluating the anti-inflammatory and analgesic activities of topical Pterocarpus santalinus in an animal model of chronic inflammation.

MATERIALS AND METHODS

Albino rats of either sex were divided into five groups of six rats each (Group I - Control, Group II -Gel base, Group III -P. santalinus paste, Group IV -P. santalinus gel, Group V- Diclofenac gel). Chronic inflammation was induced on day 0 by injecting 0.1 ml Complete Freund's Adjuvant (CFA) in sub-plantar tissue of left hind paw of the rats. Topical treatment was started from day 12 till day 28. Body weight and paw volume (Plethysmometer) were assessed on day 0, 12 and 28. Pain assessment was done using Randall and Selitto paw withdrawal method. Data was analysed using GraphPad Prism version 5. Unpaired students t-test and ANOVA followed by Tukey's test was used for comparison among groups.

RESULTS

Only topical P.santalinus gel significantly reduced the body weight (p=0.02) due to reduction in inflammatory oedema of the left limb. P. santalinus gel also showed significant reduction (p=0.03) in paw volume of rats compared to the other groups. There was significant reduction in pain threshold (gm/sec) due to chronic inflammation, with all the study drugs (p<0.05) but with P. santalinus gel, this reduction was less (p<0.001).

CONCLUSION

Gel showed significant anti-inflammatory and mild analgesic activity on topical application in rat model of chronic inflammation.

TNFα depleting therapy improves fertility and animal welfare in TNFα-driven transgenic models of polyarthritis when administered in their routine breeding

Transgenic tumour necrosis factor alpha (TNFα)-driven models of polyarthritis such as the TNF^ΔARE mouse have proven to be invaluable in delineating aspects of inflammatory disease pathophysiology in humans. Unfortunately, the onset of joint destruction and inflammation in these models represents a significant detriment to breeding management. We examined whether TNFα depleting therapy ‘infliximab’ might represent a significant refinement in routine breeding. Clinical scores of joint inflammation were assessed in TNF^ΔARE males receiving either infliximab (10 mg/kg) or saline by twice-weekly intraperitoneal injection. Joint histology and bone morphology were assessed by histological analysis and micro-computed tomography (CT), respectively. Analysis of breeding was examined retrospectively in TNF^ΔARE males prior to, and following, regular introduction of infliximab. Clinical scores of inflammation were significantly reduced in TNF^ΔARE males receiving infliximab (control 6.6 arbitrary units [AU] ± 0.88 versus infliximab 4.4 AU ± 1.4; P < 0.05), while measures of pannus invasion and bone erosion by histology and micro-CT were markedly reduced. In the breeding groups, TNF^ΔARE males receiving infliximab injections sired more litters over their breeding lifespan (control 1.69 ± 0.22 versus infliximab 3.00 ± 0.19; P < 0.005). Furthermore, prior to infliximab, TNF^ΔARE males had a 26% risk of failing to sire any litters. This was reduced to 7% after the introduction of infliximab. This study is the first to report that regular administration of infliximab is effective at suppressing disease activity and improving animal welfare in TNF^ΔARE animals. In addition, we have shown that infliximab is highly efficacious in improving breeding behaviour and increasing the number of litters sired by TNF^ΔARE males.

Arthritis models: usefulness and interpretation

Animal models of arthritis are used to better understand pathophysiology of a disease or to seek potential therapeutic targets or strategies. Focusing on models currently used for studying rheumatoid arthritis, we show here in which extent models were invaluable to enlighten different mechanisms such as the role of innate immunity, T and B cells, vessels, or microbiota. Moreover, models were the starting point of in vivo application of cytokine-blocking strategies such as anti-TNF or anti-IL-6 treatments. The most popular models are the different types of collagen-induced arthritis and arthritis in KBN mice. As spontaneous arthritides, human TNF-α transgenic mice are a reliable model. It is mandatory to use animal models in the respect of ethical procedure, particularly regarding the number of animals and the control of pain. Moreover, design of experiments should be of the highest level, animal models of arthritis being dedicated to exploration of well-based novelties, and never used for confirmation or replication of already proven concepts. The best interpretations of data in animal models of arthritis suppose integrated research, including translational studies from animals to humans.

A Comparison of the Anti-Inflammatory Effects of Cis-9, Trans-11 Conjugated Linoleic Acid to Celecoxib in the Collagen-Induced Arthritis Model

Cyclooxygenase (COX)-2 inhibitors, such as celecoxib, for chronic inflammatory disease are associated with adverse health events, while cis-9, trans-11 (c9t11) conjugated linoleic acid (CLA) is anti-inflammatory without adverse events attributed to pure intake. Mechanistically, celecoxib and c9t11 disrupt the arachidonic acid cascade; however, the equivalency of anti-inflammatory effects between these compounds is unknown. Therefore, to test the hypothesis that 0.5% dietary c9t11 reduces inflammation equivalently to a celecoxib dose intended to treat rheumatoid arthritis (RA; 5 mg/kg bw), arthritic mice received diets containing one of the following supplements: 1% corn oil (CO, w/w), 0.5% c9t11 (>91% purity) +0.5% CO, or 1% CO + 0.5, 5, or 50 mg/kg bw celecoxib, and were assessed for changes in arthritic severity over 6 weeks. Overall, arthritic severity in mice fed c9t11 was reduced (34%, P < 0.01) while celecoxib doses (0.5, 5, 50 mg/kg) reduced arthritic severity (16, 56, 48%, respectively) compared to CO-fed arthritic mice. Linear regression of the celecoxib dose-response showed 0.5% c9t11 (570 mg/kg bw) reduced arthritic severity equivalently to 1.5 mg/kg celecoxib. Interleukin-6 (IL-6) was increased in paws of arthritic mice fed CO compared to shams, but was decreased in arthritic groups fed 0.5% c9t11 and 5 mg/kg celecoxib, compared to arthritic mice fed CO (Ps ≤ 0.05). Additionally, paw and plasma IL-10 levels in arthritic mice were decreased by 5 mg/kg celecoxib, but were unaffected by c9t11 compared to CO. Results suggest dietary c9t11 may be an effective adjunct to COX-2 inhibition for treating chronic inflammation.

Anti-Arthritic Activity of Schistosoma mansoni and Trichinella spiralis Derived-Antigens in Adjuvant Arthritis in Rats: Role of FOXP3+ Treg Cells

A growing body of evidence supports the concept of helminths therapy in a variety of autoimmune diseases. Here, we aimed to investigate the protective effects of autoclaved Schistosoma mansoni antigen (ASMA) and Trichinella spiralis antigen (ATSA) on the clinical and immunopathological features of rheumatoid arthritis (RA). Adjuvant arthritis was induced by subcutaneous and intradermal injections of complete Freund’s adjuvant into the plantar surface of the right hind paw and the root of the tail, respectively. Rats were randomly assigned to serve as normal control, untreated arthritis, ASMA or ATSA-treated arthritis groups. Antigens were given by intradermal injection in two doses, two weeks apart. The development, progression of arthritic features, and the impact on animals’ gait and body weight were followed up for 4 weeks. The associated changes in serum cytokines (IL-17, IFN-γ and IL-10), joints’ histopathology and immunohistochemistry of Foxp3⁺ T regulatory cells (Tregs) were evaluated at the end of the study. Treatment with either ASMA or ATSA attenuated the progression of clinical features of polyarthritis, improved gait and body weight gain, reduced the elevated serum IL-17 and further increased both IFN-γ and IL-10. Histopathologically, this was associated with a remarkable regression of paws’ inflammation that was limited only to the subcutaneous tissue, and a significant increase in the number of Foxp 3+ cells versus the untreated arthritis group. In conclusion, both Schistosoma mansoni and Trichinella spiralis derived antigens exerted protective effect against adjuvant arthritis with better effect achieved by ASMA treatment. This anti-arthritic activity is attributed to upregulation of the Foxp3⁺ Tregs, with subsequent favorable modulation of both pro- and anti-inflammatory cytokines. The use of autoclaved parasitic antigens excludes the deleterious effects of imposing helminthic infection by using live parasites, which may pave the way to a new therapeutic modality in treating RA.