Induction Of Adjuvant Arthritis Research Articles

Evaluation of the Impact of Pistacia atlantica Desf. Oleo-gum Resin on Complete Freund’s Adjuvant-induced Arthritis in a Wistar Rat Model

Background: Pistacia atlantica Desf., also known as Atlantic pistachio or Mt. Atlas mastic tree, has been used in traditional medicine for its anti-inflammatory properties, helping to reduce inflammation in conditions like arthritis. Additionally, the tree's resin possesses antioxidant properties that can help protect against oxidative stress. The anti-arthritic efficacy of Pistacia atlantica oleo-gum resin extract (PAG) remains unvalidated, as its potential therapeutic benefits have not been substantiated. In the current investigation, we have substantiated the inhibitory properties of the PAG in mitigating the development of rheumatoid arthritis induced by Complete Freund's Adjuvant in rats. Methods: Male Wistar rats weighing 160±10 g were subjected to immunization through intradermal injection of 0.1 mL of Complete Freund's Adjuvant (CFA) into the left hind metatarsal footpad. Following the induction of adjuvant arthritis, oral administration of PAG was initiated at doses of 10, 400, and 800 mg/kg once a day. Prednisolone (10 mg/kg, daily) was employed as a positive control in this study. Various parameters, including paw swelling, arthritic index, body weight loss, spleen index, thymus index, serum cytokines, inflammatory mediators, and histological alterations, as well as nitrite glutathione and catalase level, were measured. Furthermore, the expression and activity of matrix metalloproteinase (MMP)-2 and MMP-9 were evaluated. Results: PAG exhibited noteworthy efficacy in attenuating paw swelling and reducing the arthritic index. Moreover, it resulted in enhanced body weight loss and a consequential reduction in the thymus index. PAG (400mg/kg) significantly decreased the level of serum nitrite in the intervention group, as well as the levels of serum glutathione. On the other hand, catalase activity increased, the activity of MMP-9 decreased, and the level of MMP-2 increased compared to the intervention group. The histopathological results revealed that PAG (at doses of 400 mg/kg) had the best therapeutic effects. Conclusion: In conclusion, the present study confirms the anti-arthritic activity of PAG in rats. The extract of PAG was found to prevent rheumatoid arthritis induced by Complete Freund's Adjuvant, as evidenced by the significant suppression of paw swelling and arthritic index.

Green chemistry and anti-inflammatory activity of silver nanoparticles using an aqueous curcumin extract

Rat models are sensitive to the induction of arthritis with adjuvants. Therefore, they are beneficial for studying this pathogenesis through the induction of adjuvant arthritis by injection of Complete Freund's Adjuvant (CFA). An eco-friendly green chemistry approach was utilized to synthesize silver nanoparticles (AgNPs) using an aqueous extract of curcumin root as a capping and reducing agent. AgNPs formation was evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–vis spectroscopy analyses. The study aims to assess in vivo inhibitory effect of AgNPs on complete Freund’s adjuvant-induced arthritis in rats. Therefore, male albino rats were divided into four groups: Normal control; arthritic rats untreated; arthritis rats received standard drug (dexamethasone) as a positive control for 14 days; and arthritis rats received 100 mg/kg AgNPs for 14 days. The results showed that the AgNPs exhibit anti‑inflammatory effects in rats arthritis model by reducing the edema and levels of interleukin‑6 (IL-6) and high-sensitive C‑reactive protein (hs-CRP) in the paw tissues compared to the arthritic rats untreated. Overall, these findings evidence that the AgNPs have a potential promising anti‑inflammatory effect against arthritis disease.

Novel Treatment Option for Rheumatoid Arthritis through Bone‐Targeted Delivery of Novokinin

ObjectiveRheumatoid arthritis (RA) is an autoimmune inflammatory disorder affecting about 1‐2% of the world population. RA is known to be a major cause of disability which progresses eventually to systemic complexities with high chances of early morbidity. This complex dynamic situation of inflammation is orchestrated by multiple systems in the body, including the Renin‐Angiotensin System (RAS). Angiotensin II (Ang II), a main effector peptide in the RAS, predominantly binds to Angiotensin II Type (I) receptor (AT1R). When it overproduced can result in inflammation, vasoconstriction, and oxidative stress. Ang II also binds to Angiotensin II Type (II) receptor (AT2R), which provides functional antagonism to AT1R activation. Novokinin, a synthetic peptide, promotes beneficial effects through activation of AT2R, and can be considered a potential drug candidate for alternative therapy in RA if its plasma stability and half‐life could be improved. Here, we developed a novel bone‐targeting novokinin Conjugate (Novo Conj), which binds to the bone, utilizes it as a reservoir while protecting it from enzymatic and hydrolytic degradation. We hypothesized that this delivery approach would extend the peptide half‐life and provide sustained plasma levels to elicit anti‐inflammatory activity.MethodHealthy male, Sprague Dawley rats, were induced adjuvant arthritis (AA) by administering 0.2mL of 50mg/mL of Mycobacterium butyricum through the tail base injection. Arthritic rats were divided into three groups (n=5/group) and dosed with saline (Inflamed), novokinin of 400 µg/kg (Novokinin), or an equivalent dose of 400 µg/kg of novokinin (Novo Conj). A group of healthy rats (n=5) received saline and was taken as a healthy control (Control) group. After the emergence of arthritis (i.e., 10‐12 days after adjuvant arthritis induction), animals were dosed with assigned treatment every other day for two weeks. Animals were monitored three times a week for their body weight, paw, and joint diameters. At the end of the experiment, rats were euthanized, plasma/tissues were harvested and analyzed for plasma nitric oxide (NO) and the RAS components by western blot.ResultsThe induction of AA led to a significant reduction in percent body weight gain over time, increased paws and joints swelling, and elevated plasma NO levels. AA brought an imbalance in the RAS enzymatic inflammatory axis indicator, i.e., Angiotensin‐Converting Enzyme (ACE) and ACE2 causing a reduction in ACE2/ACE and AT2R/AT1R ratio. The treatment of arthritic rats by novokinin and Novo Conj restored their body weight gain, reduced paws and joints' swelling, lowered the plasma NO level, and reinstated the imbalanced ratios of enzymes and receptors. These observed anti‐inflammatory effects were significantly higher in the Novo Conj group.ConclusionThis result indicates that the novokinin and its bone‐targeted conjugate shows anti‐inflammatory effects through the RAS. The observed enhanced impacts could be attributed to improved stability and extension of the half‐life of novokinin through its conjugation and binding to the bone. Our novel bone‐targeting delivery of novokinin offers effective alternative therapy for managing RA signs and symptoms and could be further utilized for various RAS disorders.

Prevention and Treatment of Rheumatoid Arthritis Using Bone‐Targeted Angiotensin Peptide in Rats

IntroductionThe precise etiology of Rheumatoid Arthritis (RA) remains uncertain; however, it has been shown that inflammation is responsible for activation of the renin–angiotensin system (RAS) which has been implicated in the pathogenesis and complications of RA. The main effectors of the RAS are Ang II and Ang 1‐7 which produced by Ang converting enzyme (ACE) and ACE2, respectively. Ang II is implicated in the up‐regulation of pro‐inflammatory cytokines through AT1R and contributed to the pathogenesis of RA. On the other hand, Ang 1‐7, counteract the inflammatory effects of Ang II by binding to Mas receptor and exerting anti‐inflammatory effects in experimental models of arthritis in rodent. Biological activity of Ang 1‐7 is hampered by its short half‐life due to rapid degradation by peptidases. We developed a novel bone‐seeking Ang 1‐7 conjugate (Ang Conj) and hypothesized that this novel approach will prolong half‐life and provide sustained plasma level to impose anti‐inflammatory activity. Since joint bone is the most common tissue impacted by RA, the rationale of this proposal was that, targeting of the bone with Ang Conj., as an anti‐inflammatory agent, could effectively control the signs and symptoms of arthritis.MethodsOn day one, for induction of adjuvant arthritis (AA), male Sprague Dawley rats were injected at the tail base with 0.2 mL of 50 mg/mL Mycobacterium butyricum. Arthritic animals were divided into 4 groups and treated with saline, Ang II, Ang 1‐7 and Ang Conj. A group of healthy rats received vehicle as control group. Preventive and treatment groups subcutaneously received 200 μg/kg equitant dose daily from day one for 3 weeks or after emergence of arthritis for 1 week, respectively. Animals were monitored daily for their body weight, paw and joint diameters. Animals were then euthanized, plasma/tissues were harvested and analyzed for plasma nitric oxide (NO), and the RAS components.ResultsOur results were in concert with previous reports concerning effects of inflammation on the RAS. AA presented itself by significant reduction in percent body weight gain, increased in paws, joints swelling and NO level, and reduced ACE2/ACE ratio. Administration of Ang 1‐7 or Ang Conj restored body weight gain, diminished the swelling of paws and joints and reduce plasma NO level in both treatment and preventive regimen. Consequently, the reduced ACE2/ACE balance was also restored by Ang 1‐7 and Ang Conj treatment.ConclusionThis result indicates that the prolongation of biological half‐life of Ang 1‐7 through injection of Ang Conj. exerts its anti‐inflammatory action by restoration of ACE2/ACE ratio which can augment the RAS major anti‐inflammatory component i.e. Ang 1‐7. This approach offers an effective strategy and an alternative option for management of RA patients and suggests a cardioprotective potential for this conjugate in management of inflammatory disease conditions such as RA.Support or Funding InformationStartup fund from College of Pharmacy, Idaho State UniversityPlasma nitric oxide levels in control and arthritic rats treated with Ang1‐7 or Ang1‐7 Conj.Figure 1Cardiac ACE2/ACE ratio and Mas receptor expression after treatment of control and arthritic rats with Ang 1‐7 or Ang Conj.Figure 2

Amelioration of oxidative and inflammatory changes by Swertia chirayita leaves in experimental arthritis.

The present study was aimed to determine the therapeutic effects of Swertia chirayita leaves against oxidative and inflammatory injuries in Freund's complete adjuvant (FCA) induced arthritic rats. The extract was evaluated for its phytoconstituents and various invitro antioxidant properties followed by its in vivo effects. The hydroethanolic extract of S. chirayita leaves (SCE) was orally administered (200mg/kg body weight, per day, p.o.) and the effect on the liver lipid peroxidation (LPO), antioxidant status, protein carbonyl formation along with the histopathology of liver were evaluated after induction of adjuvant arthritis. The markers of inflammation and arthritis, such as tumor necrosis factor-α (TNF-α), interleukin 1α (IL-1α), inhibition of paw edema, along with the histological and radiographic changes in the arthritic ankle joint were studied with and without SCE administration. The result showed the presence of major phytoconstituents, such as phenolic, flavonoid and terpenoid content in SCE. HPLC analysis revealed the presence of swertiamarin and amarogentin in high concentration. The extract also showed in vitro antioxidant potential which has positive correlation with the phytoconstituents. The result of in vivo study showed elevated malondialdehyde (MDA) and carbonyl content indicative of LPO and protein oxidation, respectively, with compromised intracellular antioxidant defense system in arthritic rats, which were significantly normalized after SCE treatment. The increase in serum proinflammatory cytokines (TNF- α and IL-1α) and paw edema of arthritic rats was significantly suppressed by SCE. Histology and radiographic analysis of arthritic ankle joints indicated abnormal changes. Marked reduction in inflammation and arthritic changes were observed after treatment with SCE. The present investigation suggests that hydroethanolic extract of S. chirayita leaves exhibit potential immunomodulatory effects, which may possibly be due to boosting the intracellular antioxidant defense.

The investigation of immunological effects of the new balneotherapeutic preparation glinofir used for the treatment of adjuvant arthritis

The objective of the present study was to investigate the influence of a course of application of the modified natural factors on the immunological mechanisms of regulation under experimental conditions with special reference to the application of the natural yellow clay, the clay from the Novo-Pyatigorsk quarry (the lake Tambokan) and of the new balneotherapeutic preparation glinofir based on this modified clay and designed for the treatment of adjuvant arthritis (AA). The study of anti-inflammatory activity of the externally applied balneomedicines was carried out with the use of an animal model of adjuvant arthritis. The course of applications started 3 days prior to the initiation of AA and was terminated on the 24th day of the experimental disease. The action of three balneotherapeutic preparations (Tambukan mud, yellow clay, and modified clay in the form of Glinofir) was compared after they were heated to 42 °C and applied to the animals' limbs for 15-20 minutes every second and third days. The experiments were performed on Wistar rats (n=59) divided into five groups. Group 1 was comprised of 9 healthy animals that served as controls. The animals of group 2 (n=10) presented with untreated experimentally-induced adjuvant arthritis, those of Group 3 (n=10) had model AA treated by a course of application of the Tambukan mud. The animals of group 4 (n=10) had model AA and were treated by the application of the yellow clay and those of Group 5 (n=10) with model of AA received a course of application of the modified clay. On day 37 after the induction of adjuvant arthritis, the animals developed leukocytosis (white blood cell count in the blood was 1.5 times higher than in the control group) and alterations in the composition of the lymphocyte population, viz. B-lymphocytes increased 2-2.5 times (p<0,02) while T-lymphocytes decreased (p<0,05). A course of glinofir application contributed to the restoration of the T-cytotoxic cell population (p<0,2) and influenced the regulation of pathological immune complexes (PIC) as confirmed the negative correlation between the PIC level and the absolute number of T-cytotoxic cells (r=-0,8, p<0,01). The chronic stage of AA was associated with a two-fold increase in the absorptive capacity of neutrophils. The treatment with the Tambukan mud and glinofir restored the phagocytic function of neutrophils and simultaneously reduced the blood leukocyte reaction. The anti-inflammatory action of the Tambukan mud and glinofir manifests itself in the unidirectional changes of dynamics of the characteristics of cellular and humoral immunity.

Anti-arthritic Effects of Total Flavonoids from Juniperus sabina on Complete Freund's Adjuvant Induced Arthritis in Rats.

Context:Twigs and leaves of Juniperus sabina L. have been traditionally used as the medicinal herb in China for the treatment of many ailments including rheumatoid arthritis (RA).Aims:To confirm the therapeutic effect of total flavonoids from J. sabina (JSTF) on RA-induced by Complete Freund's Adjuvant (CFA) in rats.Settings and Design:Wistar rats (200 ± 20 g) were immunized by intradermal injection of 0.1 mL of CFA into the right hind metatarsal footpad. JSTF was administered orally at the dose of 125,250 and 500 mg/kg on 14 days after the induction of adjuvant arthritis. Tripterygium glycoside (20 mg/kg) was used as a positive control. Paw swelling, arthritic score, body weight loss, serum cytokines, inflammatory mediators, and histological change were measured.Results:We found that JSTF could ameliorate paw swelling of CFA rats, and significantly inhibit arthritic score (P < 0.05). The overproduction of tumor necrosis factor alpha and interleukin 1beta were remarkably suppressed in the serum of JSTF (125,500 mg/kg) treated rats (P < 0.05). Histopathological studies also showed a marked decrease of synovial inflammatory infiltration and synovial lining hyperplasia in the joints of JSTF-treated animals. Six flavonoids were isolated and from JSTF by various chromatographic methods and identified as follows: Catechin, quercitrin, isoquercitrin, isoscutellarein 7-O-β-D-xylopyranoside, isoscutellarein 7-O-β-D-xylopyranose-(1 → 3)-α-L-rhamnoside, and rutin.Conclusions:These results suggest the potential therapeutically effect of JSTF as an anti-arthritis agent toward CFA-induced arthritis in rats, and verified therapeutic applications of J. sabina on RA in folk medicine.SUMMARY Twigs and leaves of Juniperus sabina L. have been traditionally used as the medicinal herb in China for the treatment of rheumatoid arthritisJSTF could ameliorate paw swelling of CFA rats, and significantly inhibit arthritic scoreHistopathological studies showed a marked decrease of synovial inflammatory infiltration and synovial lining hyperplasia in the joints of JSTF-treated animalsSix flavonoids were isolated and from JSTF including: Catechin, quercitrin, isoquercitrin, isoscutellarein 7-O-β-D-xylopyranoside, isoscutellarein 7-O-β-D-xylopyranose-(1 → 3)-α-L- rhamnoside, and rutin. Abbreviations used: JSTF: Total flavonoids from Juniperus sabina; CFA: Complete Freund's Adjuvant; TG: Tripterygium glycoside; TNF-α: Tumor necrosis factor alpha; IL-1β: Interleukin 1beta; IL-6: Interleukin 6; H and E: Hematoxylin and eosin.

Immune response to gut Escherichia coli and susceptibility to adjuvant arthritis in the rats.

We have investigated the humoral immune response to antigens of predominant gut aerobic bacterial strains (i.e. Escherichia coli) over the course of adjuvant arthritis and oil-induced arthritis in two inbred rat strains: Dark Agouti (DA) and Albino Oxford (AO). We report the presence of antibodies specific to proteins of E. coli in molecular weight range between 20-30 kDa in sera of diseased DA rats, and the absence of these antibodies in the sera of AO rats. In DA rats, CFA and IFA provoked a stronger antibody response to E. coli, especially of the IgG2b antibody class. Intramuscular administration of E. coli preceding the adjuvant arthritis induction had no effect on the development and course of disease, as well as on the activation of T cells in the draining inguinal lymph nodes. Higher serum levels of natural and induced IgA antibodies, combined with a higher CD3+CD26+ cell percentage were found in AO rats. The observed correlation between the serologic response to commensal flora and rats' genetic background as a defining factor for arthritis susceptibility may contribute to the process of creating a favorable (or less favorable) milieu for arthritis development.

In vivo anti-inflammatory and antiarthritic activities of aqueous extracts from Thymelaea hirsuta.

Background:The aerial parts of Thymelaea hirsuta (TH) are used as a decoction in the treatment of different pathologies in folk medicine in Morocco.Objective:The aqueous extracts were evaluated for its anti-inflammatory activity and in inhibition of adjuvant induction arthritis in male Wistar rats.Materials and Methods:The anti-inflammatory activity was carried out using carrageenan-induced rat paw edema model, and the antiarthritic activity was carried out using complete Freund's adjuvant-induced arthritis model.Results:The plant extract (500 mg/kg body weight) exhibited significant activity in acute inflammation produced 60% of inhibition after 4 h as compared with that of the standard anti-inflammatory drug, the diclofenac (100 mg/kg) which showed 40% of inhibition. In arthritis model, the extract produced 85% inhibition after 18 days when compared with the diclofenac (10 mg/kg; 72%).Conclusion:These results indicate that the aqueous extract of TH had an anti-inflammatory activity and inhibited the induction of adjuvant arthritis in male Wistar rats.

Aldehyde modification and alum coadjuvancy enhance anti-TNF-α autovaccination and mitigate arthritis in rat.

Experimental vaccination to induce antibodies (Abs) capable of cytokine antagonism shows promise as a novel immunotherapy for chronic inflammatory disease. We prepared a hybrid antigen consisting of residues 141-235 of rat TNF-α fused to the C-terminus of glutathione-S-transferase (GST), chemically modified to incorporate aldehyde residues, for development of an auto-vaccine eliciting anti-rTNF-α Abs. In rat immunization the soluble aldehyde-modified fusion protein did not generate observable Ab responses. By contrast, vaccination with the aldehyde-modified fusion protein adsorbed on alum induced anti-TNF-α autoAbs with high titer and neutralizing activity. Induction of adjuvant arthritis in rats pre-immunized with unmodified fusion protein or a control protein in alum resulted in severe inflammation and joint damage, whereas the disease induced in rats immunized with the aldehyde-bearing fusion protein in alum was markedly attenuated. Similar results were obtained in a collagen-induced rat arthritis model. Anti-collagen II IgG Ab titers did not deviate significantly in groups pre-immunized with modified fusion protein and control protein, suggesting that anti-TNF vaccination did not skew the immune response related to disease induction. This study demonstrates synergy between particulate alum and protein bound carbonyl residues for enhancement of protein immunogenicity. The antigen-specific co-adjuvant system could prove advantageous for breaking tolerance in emerging auto-vaccination therapies targeting inflammatory cytokines as well as for enhancing a broader category of subunit vaccines. Aldehyde adduction introduces a minimal modification which, together with the established use of alum as a safe adjuvant for human use, could be favorable for further vaccine development.

Effects of Xinfeng Capsule on the expression of platelet derived growth factor in synovium of adjuvant arthritis rats.

To observe the effects of Xinfeng Capsule (, XFC) on platelet parameters in peripheral blood and expression of platelet derived growth factor (PDGF) in synovium of adjuvant arthritis (AA) rats. A total of 40 male Sprague-Dawley (SD) rats were randomized into 5 groups: normal control (NC), AA model control (MC), methotrexate (MTX) treatment, Tripterygium wilfordii polycoride tablet (TPT) treatment, and XFC treatment. Excluding the NC group, the AA model was induced by intracutaneous injection of 0.1 mL Freund's complete adjuvant in the right hind limb. Induction of AA and the effects of drug treatments were assessed by voix pedis swelling, arthritis index (AI), body mass, and the pathological changes of joints and cartilage with a light microscopy. Platelet parameters in peripheral blood were detected with an automated hematology analyzer. PDGF in synovium was detected with immunohistochemical methods and PDGF mRNA expression in synovium was detected with reverse transcription polymerase chain reaction. Compared with the NC group, the MC group had significantly increased voix pedis swelling, AI, platelet (PLT) and plateletcrit (PCT) in peripheral blood and PDGF as well as PDGF mRNA in synovium (all P<0.01) and the joint cartilage was also highly degenerated. Compared with the MC group, the 3 treated groups had significantly decreased voix pedis swelling, AI, PLT, PCT, PDGF, and PDGF mRNA (P<0.01). The body mass in the XFC group was significantly higher than those in MTX and TPT groups (P <0.05). The levels of PLT, PCT, PDGF, and PDGF mRNA in the XFC group showed a decreasing tendency with no significant difference compared with the MTX and TPT groups (P >0.05). PDGF and PDGF mRNA of AA rats were positively correlated with voix pedis swelling, AI, PLT, and PCT (P <0.05 or P <0.01). The expression and biosynthesis of PDGF increase in the synovium of AA rats and correlate with voix pedis swelling, AI, PLT, and PCT. XFC can decrease the levels of PDGF, PDGF mRNA, PLT, and PCT, thereby mitigating inflammation induced by platelet activation and reducing voix pedis swelling and the AI in AA rats.

Anti-arthritic activity of Xanthium strumarium L. extract on complete Freund׳s adjuvant induced arthritis in rats

Ethnopharmacological relevanceXanthium strumarium L. fruit (Xanthiu fruit) has been traditionally used as a medicinal herb in China for the treatment of many ailments including rheumatoid arthritis. However, the anti-arthritic activity of Xanthium strumarium fruit has still not been demonstrated. In the present study, we confirmed that the extract of Xanthium strumarium (EXS) prevents rheumatoid arthritis induced by Complete Freund׳s Adjuvant (CFA) in rats. Materials and methodsMale Wistar rats (160±10g) were immunized by intradermal injection of 0.1mL of CFA into the left hind metatarsal footpad. EXS was administered orally at a dose of 300 and 75mg/kg once a day after the induction of adjuvant arthritis. Methotrexate (3mg/kg, twice a week) was used as a positive control. Paw swelling, arthritic score, body weight loss, spleen index, thymus index, serum cytokines, inflammatory mediators and histological change were measured. The chemical profile of EXS was analyzed by HPLC-DAD. ResultsWe found that the EXS significantly suppressed paw swelling and arthritic score, increased body weight loss and decreased the thymus index. The overproduction of TNF-α and IL-1β were remarkably suppressed in the serum of all EXS-treated rats, and in contrast IL-10 was markedly increased. The level of COX-2 and 5-LOX was also decreased with EXS treatment. Ten phenolic acid derivatives were identified from 14 detected peaks by HPLC-DAD with the reference substances and verified by LC–MS. ConclusionsThese results suggest the potential effect of EXS as an anti-arthritis agent towards CFA-induced arthritis in rats. Xanthium strumarium has the potential to be regarded as a candidate for use in general therapeutics and as an immune-modulatory medicine in rheumatoid arthritis.

Serum IL-10 involved in morphine tolerance development during adjuvant-induced arthritis

Opioid receptors play an important role in modulation of hyperalgesia in inflamed tissues, but chronic morphine application induces such side effects as tolerance. There is near communications between cytokines and mu opioid receptor expression. This study was aimed to assess the role of serum IL-10 in morphine tolerance development during adjuvant-induced arthritis. Adjuvant arthritis (AA) was induced on day 0 by single injection of Complete Freund's Adjuvant (CFA) into the rats' hindpaw. Hyperalgesia, edema, and spinal mu opioid receptor (mOR) variations were assessed on 0, 7, 14, and 21days of the study. For assessment of the morphine tolerance development, morphine effective dose (4mg/kg) was administered from the 14th day after CFA injection and continued until the morphine post-dose paw withdrawal latency (PWL); it did not significantly differ from the baseline. For assessment of the effects of IL-10 on tolerance induction, a neutralizing dose (ND50) of anti-IL-10 was administered daily during different stages of the study. AA induction in the right hindpaw of rats resulted in unilateral inflammation and hyperalgesia within 21days of the study. Anti-IL-10 antibody administration in the AA rats induced marked elevation of hyperalgesia compared to the AA control group. Our data also indicated that morphine effective anti-hyperalgesic dose significantly decreased in the AA rats compared to the control group, which this symptom was aligned with spinal mu opioid receptor (mOR) expression increase during AA. Moreover, there was a significant difference in morphine tolerance induction between the AA and control rats, and our results also demonstrated that IL-10 played an important role in tolerance-induction process. It can be concluded that morphine tolerance slowly progressed when administered morphine effective dose was reduced during AA chronic inflammation. On the other hand, it seems that increased level of serum IL-10 may affect morphine tolerance development during inflammation.

Therapeutic effect of 7, 3′-dimethoxy hesperetin on adjuvant arthritis in rats through inhibiting JAK2-STAT3 signal pathway

In our previous study, we have demonstrated that 7, 3′-dimethoxy hesperetin (DMHP), an active derivative of hesperidin, showed pro-apoptotic effect on synoviocytes in vitro. The present study was to investigate the potential therapeutic effect of DMHP on adjuvant arthritis (AA) in rat and its possible mechanisms. Freund's complete adjuvant was used to induce AA in rats. DMHP were administered intragastrically once a day from days 12 to 21 after AA induction. Secondary paw swelling, arthritis index, and pathological assessments were observed. IL-6 production in serum and IL-6 mRNA expression in synovium was detected by ELISA and real-time RT-PCR respectively. The expression of mRNA (JAK2, STAT3) and protein (JAK2, p-JAK2, STAT3, p-STAT3) in synovium were determined. We found that DMHP significantly inhibited hind paw swelling and arthritis index, and ameliorated pathological changes of ankle joint in AA rats. DMHP suppressed the level of IL-6 in serum and the expression of IL-6 mRNA in synovium of AA rats in a dose-dependent manner. DMHP apparently decreased mRNA expression of JAK2 and STAT3 as well as protein expression of p-JAK2 and p-STAT3 in the synovium of the AA rats. Correlation analysis indicated that p-JAK2 or p-STAT3 protein expression was highly correlated with joint damage severity. In conclusion, DMHP has a powerful therapeutic effect on AA in rats and its mechanisms might be partly related to inhibiting excessive activation of JAK2-STAT3 pathway.

Effects of cold-damp and hot-damp environment on VEGF and IL-1 expression in joint cartilage cells in adjuvant arthritis in rats

ObjectiveTo study the effects of environmental factors on the degree of injury and expression of vascular endothelial growth factor (VEGF) and interleukin-1 (IL-1) in cartilage cells of the joint in a rat model of adjuvant arthritis (AA). MethodsSD rats aged 10 months were randomly divided into 4 groups that varied by temperature and humidity housing conditions and induction of AA: a control group, a model group, a cold-damp group, and a hot-damp group. All groups except the control group were induced with AA. After 4 w, VEGF and IL-1 expression in cartilage cells of ankle joints of hind limbs were observed. ResultsMean area, optical density, and numbers of VEGF- and IL-1-positive cells in the model group, the cold-damp group, and the hot-damp group were significantly higher than that of the control group (all P<0.05). Optical density and positive cell numbers in the cold-damp group and the hot-damp group were significantly higher than that of the model group (all P<0.05). Optical density and positive cell numbers in the hot-damp group were significantly higher than that of the cold-damp group. Bone in the hot-damp and cold-damp groups was severely injured. ConclusionEnvironmental factors such as high humidity combined with either high or low temperature increase the severity of damage and expression of VEGF and IL-1 in cartilage cells of joints in rats induced with AA.

Age-depending effects of methotrexate treatment on systemic bone turnover in experimental adjuvant arthritis.

Adjuvant arthritis was induced in rats in the growth stage (aged 6 weeks) and those in the mature stage (aged 4 months), and changes in the systemic bone turnover and the effects of methotrexate (MTX, CAS 133073-73-1) were compared. After induction of adjuvant arthritis, the paw edema ratio and the urinary deoxypyridinoline (u-Dpy) level increased in both age groups. No marked changes were observed in the serum osteocalcin (s-OC) level in either group. In the 6-week-old rats, arthritis completely inhibited the bone mass, and strength of the femur and lumbar vertebral body. The 4-month-old rats showed more marked changes than the 6-week-old rats in the bone mass and strength of the lumbar, vertebral body. MTX administration (0.05, 0.1 and 0.2 mg/kg/day) resulted in significant dose-dependent inhibition of arthritis-induced changes, and the effects of MTX were similar between the two age groups. MTX was useful at each age. These results suggest that 4-month-old rats with arthritis are more appropriate as a model for evaluation of drugs for bone metabolic turnover in human chronic rheumatoid arthritis.

Effect of methotrexate on inflammatory cells redistribution in experimental adjuvant arthritis

The aim of this study was to evaluate the morphological changes in the spleen, the thymus and the knee joints of rats with experimental adjuvant arthritis induced by Mycobacterium butyricum in the incomplete Freund's adjuvant and the effect of treatment with methotrexate (MTX). Particular attention was aimed on the redistribution of granulocytes in the tissues during the inflammatory process. Clinical parameters, e.g., joint edema, body weight and of gamma glutamyl transferase (GGT) activity as an inflammatory marker, have also been determined. Induction of adjuvant arthritis caused a significant decrease in granulocyte number in the spleen and vice versa a significant increase in the knee joints, but without significant changes in the thymus. Treatment with methotrexate reversed this phenomenon by increasing the granulocyte number in the spleen and decreasing it in knee joints. MTX decreased the joint edema as well as the activity of GGT in the spleen, modified the size of the white pulp of the spleen and increased the cortex/medulla ratio in the thymus. The observed changes support the anti-inflammatory and immunomodulatory properties of MTX supporting its use as the first-line medication in patients with rheumatoid arthritis.

Chondroitin sulfate effect on induced arthritis in rats

Rodent models of osteoarthritis and rheumatoid arthritis are useful tools to study these disease processes. Adjuvant arthritis (AAR) is a model of polyarthritis widely used for preclinical testing of antiarthritis substances. We report the effect of two different doses of highly purified chondroitin sulfate (CS) pharmaceutical grade in the AAR animal model after oral administration. AAR was induced by a single intradermal injection of heat-inactivated Mycobacterium butyricum in incomplete Freund's adjuvant. The experiments included healthy animals, untreated arthritic animals, arthritic animals having been administered 300 or 900mg/kg of CS daily, 14days before AAR induction until the end of the experiment (day 28), arthritic animals having been administered 300 or 900mg/kg of CS daily, from day 1 until the end of the experiment. CS was capable of significantly reducing the severity of arthritis along with oxidative stress, a consequence of chronic inflammatory processes occurring in AAR. The CS pre-treatment regimen was effective throughout the whole subacute phase, while treatment from day 1 proved effective only in the chronic period. The effects were confirmed by improved total antioxidant status and γ-glutamyltransferase activity. CS administered under a pre-treatment regimen was also able to reduce the production of pro-inflammatory cytokines, C-reactive protein in plasma, phagocytic activity and the intracellular oxidative burst of neutrophils. CS proved to be effective in slowing down AAR development and in reducing disease markers, thus supporting its beneficial activity as a drug in humans.

Efficacy of Bacopa monniera (L.) Wettst in Alleviating Lysosomal Instability in Adjuvant-Induced Arthritis in Rats

The present study was aimed to assess the effect of Bacopa monniera extract against lysosomal instability during adjuvant-induced arthritis in rats. B. monniera extract was administered orally at a dose of 100 mg/kg body weight for 30 days to the experimental rats after the induction of adjuvant arthritis. The ability of B. monniera extract to stabilize lysosomal enzyme activities in the cartilage of control and experimental rats was done by monitoring the activities of pathophysiological enzymes such as β-glucuronidase, β-glucosaminidase, cathepsin D, hyaluronidase, collagenase and the level of protein bound carbohydrates and glycosaminoglycans (GAGs) in arthritic rats. B. monniera extract supplementation significantly inhibited lysosomal instability in different tissues studies and improved the level of glycoproteins in synovial effusate and GAG in the cartilage. To evaluate whether anti-inflammatory property of B. monniera extract was due to lysosomal stability and GAG protection, purified chloroform fraction of B. monniera (CF) was assayed for its role to modulate interleukin-6 (IL-6) expression and prostaglandin E2 (PGE2) production. Administration of CF (50 mg/kg) to arthritic rats significantly downregulated the expression of IL-6 in blood mononuclear cells and PGE2 levels in cartilage tissue. The possible mechanism of action of the B. monniera extract may be through its stabilizing action on lysosomal membranes and hence the decrease in spread of inflammation.

Effect of Porphyromonas gingivalis‐induced inflammation on the development of rheumatoid arthritis

Periodontitis is an extra-synovial chronic inflammatory condition, which has been proposed to be inter-related with rheumatoid arthritis. We investigated the effect of an established extra-synovial chronic inflammatory lesion on the induction and severity of experimental arthritis. Chronic inflammatory lesions were induced by the implantation of polyurethane sponges impregnated with heat-killed Porphyromonas gingivalis into the backs of DA rats. Thirty-five days later, adjuvant arthritis (AA) was induced in the rats by injecting a mycobacterium cell wall in complete Freund's adjuvant. The development of arthritis was then monitored for 2 weeks. Histological assessment of the implanted sponges confirmed that a chronic inflammatory lesion had been established after 21 days. Following induction of adjuvant arthritis, the severity of disease was scored and paw swelling was measured. Severe arthritis developed more rapidly in animals with a pre-existing P. gingivalis-induced inflammatory lesion elsewhere. The results show that a pre-existing extra-synovial chronic inflammatory lesion induced by P. gingivalis promotes the development of arthritis in an animal model. These findings provide further evidence for a relationship between the presence of periodontal pathogen-associated inflammation and the development of rheumatoid arthritis.