OBJECTIVE: To analyze the differences in the effects of different mechanical stimuli on cells, cytokines, and proteins in synovial fluid of osteoarthritis joints, and to elucidate the indirect mechanism by which mechanical signals remodel the synovial fluid microenvironment through tissue cells. METHODS: Systematically integrate recent literature, focusing on the regulatory effects of different mechanical stimuli on the physicochemical properties of synovial fluid. Analyze the dynamic process by which mechanical stimuli regulate secretory and metabolic activities through tissue cells, thereby altering the physicochemical properties of cytokines and proteins. RESULTS: Appropriate mechanical stimuli activate mechanical signals in chondrocytes, macrophages, and synovial cells, thereby influencing cellular metabolic activities, including inhibiting the release of pro-inflammatory factors and promoting the secretion of anti-inflammatory factors, and regulating the expression of matrix and inflammation-related proteins such as cartilage oligomeric matrix protein, peptidoglycan recognition protein 4, and matrix metalloproteinases. CONCLUSION Mechanical stimuli act on tissue cells, indirectly reshaping the synovial fluid microenvironment through metabolic activities, thereby regulating the pathological process of osteoarthritis.
Humans ; Osteoarthritis/physiopathology* ; Synovial Fluid/chemistry* ; Chondrocytes/metabolism* ; Cytokines/metabolism* ; Macrophages/metabolism* ; Stress, Mechanical ; Cartilage Oligomeric Matrix Protein/metabolism* ; Matrix Metalloproteinases/metabolism* ; Synovial Membrane/cytology*

OBJECTIVETo compare and estimate the diagnostic value and characteristic of different diagnostic methods (blood laboratory test, histological analysis, synovial fluid cytological test and microbiological examination) in detecting the presence of periprosthetic joint infection.

METHODSData of 52 patients underwent hip or knee joint revision in Peking University People's Hospital Arthritis Clinic and Research Center between July 2013 and March 2015 were analyzed retrospectively. For each patient, results of blood laboratory tests(peripheral-blood white blood cell, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), interleukin-6 (IL-6) and high-sensitivity C-reactive protein (Hs-CRP)), histological analysis, synovial fluid white cell count (SWCC), microbiological examinations (synovial fluid, tissue and prosthetic joint sonication fluid) were collected. Data were analyzed by t-test, independent sample median test or χ(2) test, respectively. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy for each method were calculated and compared by receiver operating characteristic curve.

RESULTSThere were 30 female and 22 male patients. Twenty-one patients (40.4%) were diagnosed as PJI. The levels of CRP, ESR, IL-6 and Hs-CRP in patients with PJI were higher than that in aseptic failure patients (Z=23.084, 13.499, 5.796, 17.045, all P<0.05). The sensitivities of CRP, ESR, IL-6 and Hs-CRP were 90.5%, 81.0%, 95.0% and 90.0%. The sensitivities of histological analysis and SWCC were 55.0% and 70.6%, while they had high specificity as 89.7% and 85.7%. The sensitivity of sonication fluid culture was 90.0%, which was higher than that of tissue culture (71.4%) and synovial fluid culture (65.0%) (χ(2) = 5.333, 6.400, all P<0.05).

CONCLUSIONSThe tests of CRP, ESR, IL-6 and Hs-CRP have good value in detecting PJI preoperatively. Histological analysis and SWCC have high specificity, which could help to exclude PJI. Sonication fluid culture has a higher sensitivity than tissue culture and synovial fluid culture.

Arthroplasty, Replacement, Hip ; Arthroplasty, Replacement, Knee ; Blood Sedimentation ; C-Reactive Protein ; metabolism ; Female ; Humans ; Interleukin-6 ; blood ; Knee Joint ; Male ; Prosthesis-Related Infections ; diagnosis ; ROC Curve ; Retrospective Studies ; Sensitivity and Specificity ; Synovial Fluid ; cytology

OBJECTIVETo investigate the role of natural killer-22 (NK-22) cells in the synovial fluid in the proliferation of fibroblast-like synoviocytes (FLS) in patients with rheumatoid arthritis (RA) and explore the possible signal pathway involved.

METHODSNK-22 cells in the SF of RA patients were sorted by flow cytometry. NK-22 cells were cultured for two weeks and the purity was detected by flow cytometry before stimulation with 20 ng/ml phorbol 12-myristate 13-acetate and 0.5 µmol/L ionomycin for 4 h. The level of interleukin-22 (IL-22) in the culture medium supernatant was then measured with ELISA. The proliferation of FLS in the presence of the culture supernatant of NK-22 cells was assessed with MTT assay at 24, 48 and 72 h, and the effect of IL-22 antibody on FLS proliferation was also observed. Real-time PCR and Western blotting were used to detect Stat3 mRNA and p-Stat3 protein levels, respectively, in the FLS exposed to rhIL-22 and AG490.

RESULTSNK-22 cells were successfully sorted by flow cytometry with a purity exceeding 90%. The levels of IL-22 in the supernatant of NKp44(+)NK cell culture averaged 1273.42∓254.48 pg/ml. The FLS proliferated rapidly 24, 48, and 72 h after the addition of culture supernatant of NK-22 cells (P<0.05). IL-22 antibody obviously inhibited the proliferation of FLS induced by NK-22 cell culture supernatant (P<0.05). Exposure of the FLS to rhIL-22 obviously increased cellular Stat3 expression levels, which were significantly lowered by the addition of AG490 (P<0.05).

CONCLUSIONNK-22 cells in the SF of RA patients can produce high concentrations of IL-22 to promote the proliferation of FLS through the STAT3 signal pathway.

Arthritis, Rheumatoid ; metabolism ; Cell Proliferation ; Cells, Cultured ; Fibroblasts ; cytology ; Humans ; Interleukins ; metabolism ; Killer Cells, Natural ; cytology ; metabolism ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; Synovial Fluid ; cytology ; Synovial Membrane ; cytology

Myeloid-related protein (MRP)8/MRP14 is an endogenous Toll-like receptor 4 (TLR4) ligand and is abundant in synovial fluid (SF) of rheumatoid arthritis (RA) patients. Belonging to damage-associated molecular patterns, it amplifies proinflammatory mediators and facilitates a wide range of inflammatory and autoimmune diseases. Interleukin (IL)-17-producing T-helper (Th)17 cells have a crucial role in RA pathogenesis, and IL-6 is the key factor promoting Th17 differentiation. We investigated whether the level of MRP8/MRP14 is positively associated with IL-6 and IL-17 levels in RA SF and found that MRP8/MRP14 level had a significant correlation with IL-6 and IL-17 levels in RA SF. We also observed that MRP8-induced IL-17 production by peripheral blood mononuclear cells but MRP14 did not. Upon stimulation with MRP8, IL-6 production was enhanced by RA fibroblast-like synoviocytes (FLS) and was further elevated by coculturing RA FLS with activated CD4+ T cells. Moreover, we demonstrated that MRP8-activated IL-6 production by RA FLS promoted differentiation of Th17 cells using the coculture system consisting of CD4+ T cells and RA FLS. In addition, IL-6 blockade attenuated Th17 polarization of CD4+ T cells in the cocultures. Inhibitor studies revealed that MRP8 increased IL-6 production in RA FLS via TLR4/phosphoinositide 3-kinase/nuclear factor-kappaB and mitogen-activated protein kinase signaling pathways. Our results show that MRP8 has a crucial role in stimulating IL-6 expression by RA FLS, and subsequently promotes Th17 differentiation in RA, suggesting that neutralizing MRP8 level in RA synovium may be an effective therapeutic strategy in RA treatment.
ATP-Binding Cassette Transporters/*metabolism ; Adult ; Aged ; Arthritis, Rheumatoid/*pathology ; CD4-Positive T-Lymphocytes/metabolism ; Calgranulin B/metabolism ; Cell Differentiation/*immunology ; Fibroblasts/*metabolism/pathology ; Humans ; Inflammation Mediators/metabolism ; Interleukin-17/metabolism ; Interleukin-6/*biosynthesis ; Middle Aged ; Signal Transduction/immunology ; Synovial Fluid/cytology ; Synovial Membrane/metabolism/pathology ; Th17 Cells/*pathology ; Toll-Like Receptor 4/metabolism ; *Up-Regulation

OBJECTIVETo observe beta-catenin expression of Wnt signaling pathway in rats with knee osteoarthritis, and influence of Bushen Huoxue decoction on beta-catenin and MMP-7 expression of synoviocytes in rats with knee osteoarthritis (OA).

METHODSRats model with knee osteoarthritis were established by Hulth method. Primary synoviocytes and OA synoviocytes were cultured with collagenase digestion method. The cultured synoviocytes were divided into normal group, OA model group and Bushen Huoxue decoction group. Western blotting method was used to detect beta-catenin, MMP-7 protein expression of synoviocytes after acting by Bushen Huoxue decoction for 48 h; ELISA method was used to detect MMP-7 expression of synovial supernatant.

RESULTSOA synoviocytes were cultured successfully. Western blotting showed that beta-catenin, MMP-7 expression in OA synoviocytes was significantly higher than normal group, Bushen Huoxue decoction could significantly reduce beta-catenin, MMP-7 expression; ELISA results showed that MMP-7 expression of OA synovial supernatant was significantly higher than normal synoviocytes supernatant, Bushen Huoxue decoction significantly regulated the level MMP-7 down.

CONCLUSION(1) High expression of beta-catenin in OA synoviocytes indicates that Wnt classical signal pathway is activated in rat with knee osteoarthritis; (2) High expression of MMP-7 expression in OA synoviocytes confirms the MMP-7 is downstream genes of Wnt/beta-catenin signal pathway; (3) Activation of Wnt signal pathway and increase of MMP-7 may cause degradation of articular cartilage, and promote the formation of osteoarthritis; (4) Bushen Huoxue decoction can reduce expression of MMP-7, and promote cartilage repair, which may be one of mechanisms of osteoarthritis.

Animals ; Blotting, Western ; Drugs, Chinese Herbal ; pharmacology ; Enzyme-Linked Immunosorbent Assay ; Male ; Matrix Metalloproteinase 7 ; analysis ; Osteoarthritis, Knee ; drug therapy ; metabolism ; Rats ; Rats, Wistar ; Synovial Fluid ; chemistry ; cytology ; beta Catenin ; analysis

To determine whether adiponectin may have synergistic effects in combination with the proinflammatory cytokine interleukin (IL)-1beta regarding the production of proinflammatory mediators during arthritic joint inflammation, synovial cells from rheumatoid arthritis (RA) patients were treated with adiponectin, IL-1beta, and their combination for 24 h. Culture supernatant was collected and analyzed by enzyme-linked immunosorbent assay for levels of IL-6, IL-8, prostaglandin E2 (PGE2), vascular endothelial growth factor (VEGF), and matrix metalloproteinases (MMPs). Adiponectin-mediated intracellular signaling pathways were investigated to elucidate the molecular mechanisms underlying their synergy. The association of proinflammatory mediators with adiponectin was investigated in the synovial fluid of arthritis patients. Adiponectin functioned synergistically with IL-1beta to activate IL-6, IL-8, and PGE2 expression in RA fibroblast-like synoviocytes; Levels of VEGF, MMP-1, and MMP-13 were not synergistically stimulated. Adiponectin and IL-1beta each increased the expression of both adiponectin receptor 1 and IL-1 receptor 1. However, adiponectin and IL-1beta did not synergistically support the degradation of IkappaB-alpha or the nuclear translocation of NF-kappaB. Synergistically increased gene expression was significantly inhibited by MG132, an NF-kappaB inhibitor. Supporting the in vitro results, IL-6 and IL-8 levels were positively associated with adiponectin in synovial joint fluid from patients with RA, but not osteoarthritis (OA). In conclusion, adiponectin and IL-1beta may synergistically stimulate the production of proinflammatory mediators through unknown signaling pathways during arthritic joint inflammation. Adiponectin may be more important to the pathogenesis of RA than previously thought.
Adiponectin/administration & dosage/*metabolism ; *Arthritis, Rheumatoid/metabolism/pathology ; Cells, Cultured ; Cyclooxygenase 2/metabolism ; Gene Expression Regulation/drug effects ; Humans ; *Inflammation/metabolism/pathology ; Interleukin-1beta/administration & dosage/*metabolism ; Interleukin-6/metabolism ; Interleukin-8/metabolism ; Joints/metabolism/pathology ; Matrix Metalloproteinases ; NF-kappa B/metabolism ; Obesity/metabolism/pathology ; Osteoarthritis ; Receptors, Adiponectin/metabolism ; Receptors, Interleukin-1/metabolism ; *Synovial Fluid/cytology/metabolism

OBJECTIVETo evaluate the effects of Artesunate on tumor necrosis factor alpha (TNF-alpha), monocyte chemoattractant protein (MCP-1), and on reduced activation normal T cell expressed and secreted (RANTES) in the serum and the synoviocyte culture supernate of collagen-induced arthritis (CIA) rats.

METHODSEighty male Wistar rats were selected to establish the CIA rat model. On the 6th day after modeling, 60 rats with the sum of arthritis index of right metapedes and two propodium > or = 6 were selected, and randomly divided into 6 groups (n = 10), i.e., the blank control group, the CIA model control group (treated with normal saline, abbreviated as the CIA group), the MTX positive control group (abbreviated as the MTX group), the large dose Artesunate group (at the daily dose of 20 mg/kg), the moderate dose Artesunate group (at the daily dose of 10 mg/ kg), and the small dose of Artesunate group (at the daily dose of 2.5 mg/kg). Mice were sacrificed 7 days of immune injection and their venous blood was collected to obtain the serum. Meanwhile, the synovial tissues of the knee joint were taken by aseptic techniques and primary cultured for 48 h. The supernate was collected by centrifuge. The changes of MCP-1, RANTES, and TNF-alpha in the serum and the synoviocyte culture supernate were observed in each group before and after treatment using ELISA.

RESULTSArtesunate significantly decreased the expressions of TNF-alpha in the serum and the synoviocyte culture supernate, showing significant difference when compared with the model control groups (P < 0.05). There was no statistical difference in the large dose Artesunate group and the moderate dose Artesunate group when compared with the MTX group (P > 0.05). But statistical difference existed in the large dose Artesunate group, the moderate dose Artesunate group, and the MTX group when compared with the small dose Artesunate group (P < 0.05). Artesunate could significantly decrease the expressions of MCP-1 and RANTES in the serum and the synoviocyte culture supernate, showing statistical difference when compared with the model control group (P < 0.05). But no statistical difference existed when compared with the MTX group (P > 0.05).

CONCLUSIONThe mechanism of anti-inflammatory action and immune regulation of Artesunate might be correlated with the inhibition of inflammatory factor TNF-alpha and chemotactic factors MCP-1 and RANTES.

Animals ; Artemisinins ; pharmacology ; Arthritis, Experimental ; blood ; metabolism ; Cells, Cultured ; Chemokine CCL2 ; blood ; metabolism ; Chemokine CCL5 ; blood ; metabolism ; Disease Models, Animal ; Male ; Rats ; Rats, Wistar ; Synovial Fluid ; cytology ; metabolism ; Tumor Necrosis Factor-alpha ; blood ; metabolism

OBJECTIVETo investigate the effect of NK-22 cells isolated from the synovial fluid (SF) of patients with rheumatoid arthritis (RA) on the proliferation of fibroblast-like synoviocytes and explore its possible mechanism.

METHODSThe proportions of NK-22 cells in the peripheral blood (PB) and the SF of 20 RA patients and 20 healthy individuals were determined by flow cytometry. NK-22 cells in the SF sorted by flow cytometry were cultured for two weeks followed by a 4-h stimulation with 20 ng/ml phorbol 12-myristate 13-acetate and 0.5 µ mol/L ionomycin. The culture supernatant of NK-22 cells was then harvested, in which the levels of IL-22 and TNF-α were measured by ELISA. The fibroblast-like synoviocytes were exposed to the culture supernatant for 24, 48, 72, and 96 h, and the changes in the cell proliferation were detected by MTT assay.

RESULTSRA patients showed a significantly greater proportion of NK-22 cells in both the SF and PB than the normal control subjects (P<0.05). NK-22 cells sorted by flow cytometry reached a purity exceeding 90%, and the levels of IL-22 and TNF-α in the culture supernatant of NK-22 cells cultured for two weeks were 941.16 pg/ml and 368.1 pg/ml, respectively. The culture supernatant of NK-22 cells caused a rapid proliferation of the fibroblast-like synoviocytes at 24, 48, 72, and 96 h after the exposure.

CONCLUSIONNK-22 cells in the SF of RA patients can promote the proliferation of fibroblast-like synoviocytes possibly due to the capacity of NK-22 cells to produce IL-22 and TNF-α.

Adult ; Arthritis, Rheumatoid ; pathology ; Case-Control Studies ; Cell Proliferation ; Cells, Cultured ; Female ; Fibroblasts ; cytology ; Flow Cytometry ; Humans ; Interleukins ; metabolism ; Killer Cells, Natural ; cytology ; Male ; Middle Aged ; Synovial Fluid ; cytology ; Tumor Necrosis Factor-alpha ; metabolism

Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disorder that causes the immune system to attack the joints. Transforming growth factor-beta1 (TGF-beta1) is a secreted protein that promotes differentiation of synovial fibroblasts to alpha-smooth muscle actin (alpha-SMA)-positive myofibroblasts to repair the damaged joints. Synovial fluid from patients with RA (RA-SF) induced expression of alpha-SMA in human adipose tissue-derived mesenchymal stem cells (hASCs). RA-SF-induced alpha-SMA expression was abrogated by immunodepletion of TGF-beta1 from RA-SF with anti-TGF-beta1 antibody. Furthermore, pretreatment of hASCs with the TGF-beta type I receptor inhibitor SB431542 or lentiviral small hairpin RNA-mediated silencing of TGF-beta type I receptor expression in hASCs blocked RA-SF-induced alpha-SMA expression. Small interfering RNA-mediated silencing of Smad2 or adenoviral overexpression of Smad7 (an inhibitory Smad isoform) completely inhibited RA-SF-stimulated alpha-SMA expression. These results suggest that TGF-beta1 plays a pivotal role in RA-SF-induced differentiation of hASCs to alpha-SMA-positive cells.
Actins/*metabolism ; Adipose Tissue/*cytology ; Arthritis, Rheumatoid/*metabolism ; Humans ; Mesenchymal Stem Cells/*metabolism ; Receptors, Lysophosphatidic Acid/metabolism ; Signal Transduction ; Smad2 Protein/metabolism ; Stress Fibers/metabolism ; Synovial Fluid/*metabolism ; Transforming Growth Factor beta1/*metabolism

OBJECTIVETo study the effect of geniposide-acid(GA) on the anti-inflammatory action for adjuvant-induced arthritis (AA) rats and the proliferation of synoviocytes in AA rats and the feasible mechanism of apoptosis in vitro.

METHODForty-eight health male Wistar rats were divided randomly into six groups and were administered respectively with 200, 100, 50 mg x kg(-1) GA and 0.75 mg x kg(-1) MTX and normal sodium (normal or model control group) for four weeks when right posterior paw pads of rats excluding normal control group were injected intrademally with complete Freund's adjuvant after 19 days. The left posterior paws swelling degree, swelling inhibition ratio and arthritis index of secondary inflamation were detected. The TNF-alpha and IL-1beta proteins in serum of rats were assayed by enzyme linked immunosorbent assay (ELISA) kits. The synovial fibroblasts of AA rats were exposed to 1-4 micromol x L(-1) GA or 4 micromol x L(-1) MTX. The effect of GA on the proliferation of synoviocytes was detected by MTT assay. The morphologic change of apoptosis cells was observed by Hoechst/PI double stainning and fluorescence microscope. The rate of apoptosis cells was analyzed by flow cytometry. The mRNA expresstion of Bcl-2 and Bax gene was detected by reverse transcription PCR (RT-PCR).

RESULT200 mg kg(-1) or 100 mg kg(-1) GA could decrease significantly the paw swelling degree, arthritis index and the level of TNF-alpha and IL-1beta proteins in serum of AA rats (P < 0.05 or P < 0.01) with 25.4%, 21.37% of the swelling inhibition ratio respectivly, 34.61%, 28% of protein inhibition ratio of TNF-alpha and 29.05%, 21.65% of that of IL-1beta. GA(1-4 micromol x L(-1)) inhibitated significantly the proliferation of synoviocytes culcured for 5 days. Flow cytometry showed that 1, 2, 4 micromol x L(-1) GA increased obviously the rate of apoptosis cells, the apoptosis ratios were 15.8%, 24.3%, 40.7% respectivly (P < 0.01). RT-PCR showed GA could decrease the expression level of Bcl-2 gene but increase that of Bax gene (P < 0.05 or P < 0.01).

CONCLUSIONGA could inhibit the secondary inflamation of AA rats and decrease the level of TNF-alpha and IL-1beta protein in the AA rats serum. GA could inhibit the proliferation of AA rat synoviocytes in vitro and induce apoptosis which mechanism was concerned with down-regulating the mRNA expression of Bcl-2 and up-regulating that of Bax.

Animals ; Anti-Inflammatory Agents ; administration & dosage ; Apoptosis ; drug effects ; Arthritis, Experimental ; chemically induced ; drug therapy ; immunology ; physiopathology ; Cytokines ; immunology ; Disease Models, Animal ; Freund's Adjuvant ; adverse effects ; Glucosides ; administration & dosage ; Humans ; Iridoid Glucosides ; Iridoids ; administration & dosage ; Male ; Random Allocation ; Rats ; Rats, Wistar ; Synovial Fluid ; cytology ; drug effects ; immunology