REGULAR EXPRESSION OF DISCOIDIN DOMAIN RECEPTOR 2 IN THE IMPROVED ADJUVANT-INDUCED ANIMAL MODEL FOR RHEUMATOID ARTHRITIS

Objective To investigate the expression of discoidin domain receptor 2 (DDR2) of fibroblast-like synovial cells in im- proved adjuvant-induced animal (AIA) model for rheumatoid arthritis (RA) and to provide evidence for DDR2’s antagonist use clinically. Methods AIA was modified by administrating 0.1 mL of complete Freund’s adjuvant (CFA, mixed with 5 mg Bacillus Calmette-Guerin vaccine/mL) into rats’ right hind paws and 0.125 mL tumor necrosis factor-α (2 U/mL) into right ankles and subpatellar fatty tissue. The expression of DDR2 in fibroblast-like synovial cells was assessed using immunohistochemistry, immunofluorescence histochemistry, and in situ hybridization methods. Levels of anti-collagen II antibody were measured using enzyme-linked immunosorbent assay. Results Given the terms mentioned above, we found a more practical rat model, apparently decreasing immunization time (average 3-5 days). DDR2 can be detected upon the 15th day of immunization; expression gradually increased with time going on, and reaching a peak 35 days after immunization before gradually decreasing. Serum anti-collagen II antibody showed similar expression patterns as DDR2, but reached peak later than DDR2, about 40 days after immunization. Conclusion Regular expression of DDR2 in animal models infers its important role in the pathological process of RA.

JAK1-STAT3 blockade by JAK inhibitor SHR0302 attenuates inflammatory responses of adjuvant-induced arthritis rats via inhibiting Thl7 and total B cells

Aim To investigate the effects of JAK inhibitor （SHR0302） on adjuvant-induced arthritis （AA） rats and the partial mechanisms focused on T, B lymphocyte subsets through JAK1-STAT3 pathway, including Thl7, Treg, total B cells and memory B cells. Methods Animals were divided randomly into 6 groups including normal control, AA, SHR0302 （0.3, 1.0, 3.0 nag · kg^-1, ig） and MTX （0.5 nag · kg^-1 , ig） . The effects of SHR0302 on AA rats by evaluating arthritis index, arthritis global assessment and paw swelling degree, histopathology of joint and spleen, inflammatory cytokine and antibody production in serum. We examined the proliferation of T, B and FLS by CCK8 kit; Thl7, Treg, total B and memory B cell proportion was measured by flow cytometry; Cytokines TNF-αβ, IL-1β, IL-10, IL-17 and antibody IgG1, IgG2a levels in serum were measured by ELISA kits; The ex- pression of p-JAK1 and p-STAT3 was measured by Western blot analysis. Results SHR0302 suppressed the se- verity of AA rats by attenuating the arthritis index, arthritis global assessment and paw swelling degree, and allevia- ted histopathology of spleen and joint of AA rats. SHR0302 can inhibit the proliferation of T, B and FLS, and down-regulated cytokines TNF-α, IL-1β, IL-17 and antibody IgG1, IgG2a levels, and suppressed the proportion of Thl7 and total B, and inhibited JAK1-STAT3 phosphorylation; There was no significant effect on Treg function and memory B cell proportion. Conclusion SHR0302 may attenuate the severity of AA rats, partially through signifi- cantly reducing Thl7 function and total B cell proportion by inhibiting JAK1-STAT3 phosphorylation.

The effects of Fumaderm~ on immunological function and cytokines in a rat model of adjuvant-induced arthritis

Objective To study the therapeutic effect of Fumaderm in Freund’s complete adjuvant-induced arthritis(AIA)in Spraque-Dawley rats.Methods Adjuvant-induced arthritis(AIA)was established by intradermal injection of 0.1 mL of Freund’s complete adjuvant(CFA)in the palmar surface of the right hindpaw and Fumaderm was delivered by oral gavage for 28 days.After CFA injection,the edema of the hindpaw was determined every two days.On 28 days after CFA injection,the lymphocyte subsets of peripheral blood and the cytokines were determined by flow cytometry,meanwhile the histopathological examination of ankle-joints of the animals was performed.Results Fumaderm had a significant therapeutic effect on AIA.The hindpaw swelling was reduced significantly in a dose-dependent manner.The ratio of peripheral blood T lymphocytes was improved obviously.Multiparameter cytokine analysis from peripheral blood CD4+ T cells showed a decrease of proinflammatory cytokines and an increase of anti-inflammatory cytokines in Fumaderm treated animals.A strongly reduced inflammatory response in the joint synovium was observed.Conclusion Fumaderm has potential anti-inflammatory effects on AIA rats.Further investigation is needed to elucidate the molecular mechanism involved in the clinical effect observed in the AIA model.

Paeoniflorin-6′-O-benzene sulfonate ameliorates progression of adjuvant-induced arthritis by inhibiting interaction between Ahr and GRK2 of fibroblast-like synoviocytes

OBJECTIVE Aryl hydrocarbon receptor(Ahr)is thought to be a crucial factor that regulates immune responses,which may be involved in the pathogenesis of autoimmune inflammation including rheumatoid arthritis(RA).The results of our group in recent years have shown that CP-25,a novel ester derivative of paeoniflorin,has a good effect on improving RA animal models.However,whether the anti-arthritis effect of CP-25 is related to Ahr remains unclear.METHODS CP-25 treatment ameliorated adjuvant-induced arthritis(AA),a mouse model of RA,by inhibiting Ahr-related activities in fibroblasts like synoviocytes(FLS).AA rats were treated with CP-25 or paroxetine from day 17 to 33 after immunization.RESULTS CP-25 alleviated arthritis symptoms and the pathological changes,decreased the expression of Ahr in the synovium and FLS of AA rats.Besides,treatment with CP-25 reduced the proliferation and migration of MH7A caused by Ahr activation.In addition,we also demonstrated that CP-25 down-regulated the co-expression and co-localization of Ahr and G protein-coupled receptor kinase 2(GRK2)in MH7A.CONCLUSION The data presented here demonstrated that CP-25 suppressed FLS dysfunction in rats with AA,which were associated with reduced Ahr activation and the interaction between Ahr and GRK2.

Ginsenoside Rb1 attenuates adjuvant-induced arthritis in rats through inactivation of NF-κB signaling pathway

OBJECTIVE To investigate the anti-arthritic effect and mechanism of action of ginsenoside Rb1 on adju⁃vant-induced arthritis(AIA)in rats.METHODS Male SD rats were received 0.1 mL injections of FCA(10 g·L^-1)emulsion into the right hind metatarsal foot pad for arthritis induction.After that,rats were randomly divided into six groups,namely control group,untreated group,dexamethasone(DEX,2.5 mg·kg^-1)group,low(5 mg·kg^-1),medium(10 mg·kg^-1)and high(20 mg·kg^-1)doses of ginsenoside Rb1 groups,and treated intraperitoneally at the above dosage once a day for 2 weeks.After treatment,paw swelling and arthritis indexes were evaluated,the thymus and spleen index were calculated as well.HE staining were used to observe the joint histopathology in rats.Rat ELISA kits were used to determinate the TNF-α,IL-1βand IL-6 levels.Western blotting were used to detect the related protein expression of NF-κB signaling pathway in the tissues of inflamed joints.RESULTS Rb1 significantly decreased the paw swelling and arthritis index,Compared with AIA group.HE staining results revealed that medium and high doses of Rb1 significantly reduced synovial inflammatory cell infiltration,synovial lining hyperplasia and bone destruction,compared with AIA group.Elisa results showed that Rb1 significantly decreased the TNF-α,IL-1β and IL-6 levels(P<0.05,P<0.01).Western blotting results revealed that the expression of p-IκB and p-P65 were significantly reduced in 20 mg·kg^-1 of Rb1 group,compared with AIA group(P<0.05,P<0.01).CONCIUSION Rb1 manifests therapeutic anti-inflammatory effects on rats with AIA,poten⁃tially through a mechanism of inhibiting activation of the NF-κB.

Effect of Cornus officinalis glycoside on adjuvant-induced arthritis in rats

The aim of this study was to explore the effect of Comus officinalis glucosides （COG） on adjuvant-induced arthritis in rats and its mechanism. Seventy-two rats were divided into six groups of norreal, model, Dexasone （0. 125 mg/kg）, high-dose COG （240 mg/kg）, mid-dose COG （120 mg/kg）, and low-dose COG （60 mg/kg）. Rat arthritis was induced by injection of Freund＇s complete adjuvant in the hind paws. All treatment started from the day the arthritis was induced. The edema degree of the adjuvant injection location was determined on days 1, 3, 5, 7, 9, 11, 13, 15, 17, 20, 23 and the oppo- site side was observed on days 11, 13, 15, 17, 20, 23 after the injection of adjuvant. All rats were sacrificed on day 24 after the injection of adjuvant for microscopic examination of the ankle, and for the study of the immunological molecular mechanism. The results showed that the COG significantly suppressed both the primary and secondary edema, improved pathological injuries of adjuvant arthritis （AA） rat ankles, significantly suppressed the proliferation of T lymphocytes and DTH reaction. It significantly suppressed IL-1, IL-6 and TNF-α production from peritoneal macrophages and PGE2 in plasma. In conclusion, the Comus officinalis glucosides （COG） is able to prevent and cure the rat adjuvant-induced arthritis, and can suppress the production of pro-inflammatory cytokine IL-1, IL-6, TNF-α and PGE2.

Deciphering the pharmacological mechanism of Guan-Jie-Kang in treating rat adjuvant-induced arthritis using omics analysis

Traditional Chinese medicine (TCM) formulas have attracted increasing attention worldwide in the past few years for treating complex disease including rheumatoid arthritis. However, their mechanisms are complex and remain unclear. Guan-Jie-Kang (GJK), a prescription modified from “Wu Tou Decoction,” was found to significantly relieve arthritis symptoms in rats with adjuvant-induced arthritis after 30-day treatment, especially in the 24 g/kg/day group. By analyzing 1749 targets related to 358 compounds in the five herbs of GJK, we identified the possible anti-arthritis pathways of GJK, including the calcium signaling and metabolic pathways. Bone damage levels were assessed by micro-computed tomography, and greater bone protective effect was observed with GJK treatment than with methotrexate. Receptor activator of nuclear factor kB ligand (RANKL)-RANK signaling, which is related to calcium signaling, was significantly regulated by GJK. Moreover, a target metabolomics assay of serum was conducted;17 metabolic biomarkers showed significant correlations with treatment. An integrated pathway analysis revealed that pyruvate metabolism, purine metabolism, and glycolysis metabolism were significantly associated with the effects of GJK in arthritis treatment. Thus, this study establishes a new omics analytical method integrated with bioinformatics analysis for elucidating the multi-pathway mechanisms of TCM.

Human umbilical cord mesenchymal stem cells as treatment of adjuvant rheumatoid arthritis in a rat model

AIM:To investigate the effect of human umbilical cord stem cells,both mesenchymal and hematopoietic(CD34+),in the treatment of arthritis.METHODS:Mesenchymal stem cells(MSCs) and hematopoietic(CD34+) stem cells(HSC) were isolated from human umbilical cord blood obtained from the umbilical cord of healthy pregnant donors undergoing fullterm normal vaginal delivery.MSC,HSC,methotrexate(MTX) and sterile saline were injected intra-articularly into the rat hindpaw with complete freunds adjuvant(CFA) induced arthritis after the onset of disease(day 34),when arthritis had become well established(arthritis score ≥ 2).Arthritic indices were evaluated and the levels of interleukin(IL)-1,tumor necrosis factor(TNF)-α and interferon(IFN)-γ and anti-inflammatory cytokine IL-10 in serum were determined using enzyme-linked immunosorbent assay.Animals of all groups were sacrificed 34 d after beginning treatment,except positive control(PC) which was sacrificed at 10,21 and 34 d for microscopic observation of disease progression.We used hematoxylin,eosin and Masson's trichrome stains for histopathological examination of cartilage and synovium.RESULTS:The mean arthritis scores were similar in all groups at 12 and 34 d post immunization,with no statistical significant difference.Upon the injection of stem cells(hematopoietic and mesenchymal),the overall arthritis signs were significantly improved around 21 d after receiving the injection and totally disappeared at day 34 post treatment in MSC group.Mean hindpaw diameter(mm) in the MSC rats was about half that of the PC and MTX groups(P = 0.007 and P = 0.021,respectively) and 0.6 mm less than the HSC group(P = 0.047),as indicated by paw swelling.Associated with these findings,serum levels of TNF-α,IFN-γ and IL-1 decreased significantly in HSC and MSC groups compared to PC and MTX groups(P < 0.05),while the expression of IL-10 was increased.Histopathological examination with H and E stain revealed that the MTX treated group showed significant reduction of leucocytic infiltrate and hypertrophy of the synovial tissue with moderate obliteration of the joint cavity.Stem cells treated groups(both hematopoietic CD34+ and mesenchymal),showed significant reduction in leucocytic infiltrate and hypertrophy of the synovial tissue with mild obliteration of the joint cavity.With Masson's trichrome,stain sections from the PC group showed evidence of vascular edema of almost all vessels within the synovium in nearly all arthritic rats.Vacuoles were also visible in the outer vessel wall.The vessel became hemorrhagic and finally necrotic.In addition,there was extensive fibrosis completely obliterating the joint cavity.The mean color area percentage of collagen in this group was 0.324 ± 0.096,which was significantly increased when compared to the negative control group.The mean color area percentage of collagen in hematopoietic CD34+ and mesenchymal groups was 0.176 ± 0.0137 and 0.174 ± 0.0197 respectively,which showed a marked decrement compared to the PC group,denoting a mild increase in synovial tissue collagen fibers.CONCLUSION:MSC enhance the efficacy of CFAinduced arthritis treatment,most likely through the modulation of the expression of cytokines and amelioration of pathological changes in joints.

The pain-related behavior changes correlate with the bone damage in a rat model of rheumatoid arthritis

In view of the extensive bone damage in rheumatoid arthritis, we used a commonly utilized animal model to detect behavioral changes in pain-related and the bone damage during the early disease, and to explore the correlation between bone damage and pain-related behavioral changes. Methods： Arthritis were induced in Sprague-Dawley （SD） male rats by injecting complete Freund＇s adjuvant （CFA） into the tails. Pain-related behavior changes were studied using the Hargreaves, VonFrey, and acetone tests on the 0, 7, 14, day and 28 day after CFA injection. The rats were sacrificed according the same schedule. The bone damage of the right proximal tibia was studied by microCT scan and bone histological slices. Results： Animals developed soft tissue inflammation and polyarthritis on 7 days after CFA injection, and arthritic score proved obvious arthritis were established within the study period. Mechanical hyperalgesia and cold allodynia were present in the affected hind paw from the 7 day through the 28 day, but the heat hyperalgesia and the mechanical allodynia lasted a short time after CFA injection. Trabecular bone number （Tb.N）, Tissue Mineral Content （TMC） and Bone Volume to Tissue Volume （BV/TV） in the proximal tibia by microCT scan were also reduced after induction, especial 14 days after CFA injection. The bone histologicalslices showed the trabecular bone and proteoglycan diminished, the bone damage severity scores became more severely on the 7 day after CFA injection. Using analysis of covariance, these changes had statistical significance compared with baseline. By linear regression analysis demonstrated mechanical hyperalgesia and cold allodynia correlated well with arthritic score, bone damage parameters and bone damage severity scores. Conclusion： Adjuvant-induced arthritis （AA） were observed after CFA injection and lasted within the later experimental period. Pain-related behavioral changes were observed in the early time of AA. Bone damage was also occurred with arthritis development. Pain-related behavioral change correlated well with arthritic score and bone damage parameters

Paeoniflorin-6＇-O-benzene sulfonate, a novel compound, protects against autoimmune arthritis by modulating inflammation and bone damage

Aim Paeoniflorin （Pae） is the principal bioactive component of total glucosides of peony （TGP）, which has been widely used in therapy for rheumatoid arthritis （RA）. Paeoniflorin-6＇-O-benzene sulfonate （code： CP-25） , a novel compound that is a newly ester derivatives of Pae, was evaluated in rats with adjuvant-induced ar- thritis （AA） to study its potential anti-arthritic activity. Methods AA rats were randomly divided into different groups and then treated with CP-25 （25, 50, 100 mg· kg^-1） and methotrexate （0. 5 mg · kg^-1）, from day 16 to day 32 after immunization. Arthritis severity was evaluated by clinical manifestation and histopathological examina- tion. The cells proliferation was determined by CCK-8 assay. Activities of IL-1β, IL-6, IL-17, IL-10, TGF-β1, TNF-oL, IIANKL and OPG were assessed by ELISA. The subsets of CD4 ＋T cells were assayed by flow cytometry. Results CP-25 treatment effectively reduced clinical severity scores and blinded histopathological scores compared with AA groups. CP-25-treated rats exhibited a decrease in the pro-inflammatory cytokines （IL-1β, IL-6, IL-17, and TNF-α） , coupled with an increase in the anti-inflammatory cytokines IL-10 and TGF-β1 in serum and macro- phages of AA rats. The flow cytometry analyses of CD4 ＋T cells dramatically demonstrated the immunomodulatory effects of CP-25 on abnormal immune dysfunction. Apart from the anti-inflammatory activity, treatment with CP-25 inhibited the fibroblast-like synoviocyte （FLS） activation and function. Furthermore, CP-25 treatment of AA rats restored the balance between RANKL and OPG in favor of its anti-osteoclastic effects. Conclusions Data presen- ted here demonstrated that administration of CP-25 significantly inhibited the progression of rat AA, with reductions both in arthritic inflammation and bone damage. The protective effects of CP-25 in AA highlight an attribute that is potential as an ideal new anti-arthritic agent for the treatment with human RA.

EFFECT OF ELECTROACUPUNCTURE ON THE IMMUNOREACTIVITY OF FOCAL CUTANEOUS μ-OPIOID RECEPTOR IMMUNOREACTION-POSITIVE FIBERS IN ADJUVANT ARTHRITIC RATS

Objective：To study the effect of μ-opioid receptor （MOR） expression in the inflammatory skin tissue and the effect of electroacupuncture （EA） on the topical immunoreaction （IR） of MOR positive fibers in adjuvant arthritic （AA） rats. Methods： A total of 48 SD rats were randomized into control （n = 8）, model （n = 10）, focus-side-EA （n = 10）, non-acupoint-EA （n = 10）, and healthy-side-EA （ n = 10） groups. AA model was established by subcutaneous injection of complete Freund＇s adjuvant （CFA, 50 μL） into the left hind paw. EA （4-16 Hz, 0.5-1.5 V） was applied to “Huantiao” （环跳 GB 30） and“Yanglingquan” （阳陵泉 GB 34） on the focus or healthy side and non-acupoints for 30 min. Non-acupoints used were the two sites 5 mm to GB 30 and GB 34 on the healthy side. The topical MOR IR-positive fibers in the dermal and subcutaneous tissues of the focus was stained with immunohistochemical method. The severity of pain was detected by foot （anklejoint）-bending test. Results： Compared with model group, the “foot-bending test” score decreased significantly in focus-side-EA group on the 9^th and 11^th day （P〈 0.05） and in non-acupoint-EA group on the 8^th, 9^th and 11thd after injection of CFA （P 〈 0.05）, indicating that EA of bilateral GB 30 and GB 34 and non-acupoints all can relieve pain. From the 13^th day on, no significant differences were found in “foot-bending test” scores among the 3 EA groups and model group （P 〉0.05）. In comparison with control group, the area values of MOR IR-positive nerve fibers in the focus tissue were significantly higher in 3 EA groups （P 〈 0.05）. The area values of MOR IR-positive nerve fibers in the focus in model group and 3 EA groups were significant higher than that in control group （P〈 0.05）. Compared with model group, the area values of MOR IR-positive fibers in focus-side-EA group and healthy-side-EA group increased significantly （P 〈 0.05）; while those of MOR IR-positive fibers in non-acupoint-EA group and healthy-side-EA group were significantly lower than that in focus-side-EA group （ P 〈 0.05 ）, and no significant differences were found among model group, healthy-side-EA group and non-acupoint-EA group in the area of MOR IR-positive fibers （P 〉0.05）, indicating a stronger effect of EA of acupoints on the focus side. Conclusion： EA of GB 30 and GB 34 can relieve inflammatory pain and up-regulate the expression of MOR IR-positive fibers in the focal skin tissues in AA rats, exerting anti-inflammatory and analgesic effects.

Madecassoside impedes invasion of rheumatoid fibroblast-like synoviocyte from adjuvant arthritis rats via inhibition of NF-κB-mediated matrix metalloproteinase-13 expression

Fibroblast-like synoviocytes(FLS) play a pivotal role in Rheumatoid arthritis(RA) pathogenesis through aggressive migration and invasion. Madecassoside(Madec), a triterpenoid saponin present in Centella asiatica herbs, has a potent anti-inflammatory effect. In the present study, Madec exerted an obvious therapeutic effect in reversing the histological lesions in adjuvant-induced arthritis(AIA) rats. To recognize the anti-rheumatoid potentials of Madec, we further investigated whether Madec interfered with FLS invasion and metalloproteinase(MMP) expression. In cultures of primary FLS isolated from the AIA rats, Madec(10 and 30 μmol·L–1) was proven to considerably inhibit migration and invasion of FLS induced by interleukin 1β(IL-1β), but exhibiting no obvious effect on cell proliferation. Madec repressed IL-1β-triggered FLS invasion by prohibiting the expression of MMP-13. Additionally, Madec suppressed MMP-13 transcription via inhibiting the MMP-13 promoter-binding activity of NF-κB. Our results further showed that Madec down-regulated the translocation and phosphorylation of NF-κB as demonstrated by Western blotting and immunofluorescence assays. In conclusion, our results suggest that Madec exerts anti-RA activity via inhibiting the NF-κB/MMP-13 pathway.

Anti-rheumatoid arthritic effect of volatile components in notopterygium incisum in rats via anti-inflammatory and anti-angiogenic activities

Notopterygium incisum(QH) has been used for the treatment of rheumatoid arthritis(RA), and volatile oils may be its mainly bioactive constituents. The present study was designed to analyze the volatile compounds in QH and to determine the anti-arthritic capacity of Notopterygium volatile oils and the potential mechanism of action. The volatile compounds analysis was conducted by GC-MS. The anti-arthritic capacity test of the volatile oils was conducted on adjuvant-induced arthritis(AIA) rats. The anti-inflammatory property was tested in NO release model in RAW 264.7 cells. Endothelial cells were used to evaluate the anti-proliferative and anti-tube formative effects. 70 compounds were analyzed by GC-MS in the volatile oils. Notopterygium volatile oils weakened the rat AIA in a dose-dependent manner(2, 4, and 8 g crude drug/kg). The NO production by RAW 264.7 was decreased by more than 50% in Notopterygium volatile oils(5, 15, and 45 μg·mL^(-1)) pretreated groups. Notopterygium volatile oils also inhibited EAhy926 cell proliferation and further delayed EAhy926 cell capillary tube formation in a concentration-dependent manner. The anti-NO productive, anti-proliferative, and anti-tube formative effects of Notopterygium volatile oils strongly suggested that the therapeutic effect of QH in AIA might be related to the potent anti-inflammatory and anti-angiogenic capacities of the volatile oils.