白细胞介素1β,肿瘤坏死因子α在膝关节原发性骨关节病发病中 …

目的 探讨白细胞介素１β（ＩＬ－１β）肿瘤坏死因子α（ＴＮＦ－α）在膝关节原发性骨关节病（ＯＡ）发病中的作用。方法 提取１６例ＯＡ患者（ＯＡ组）５例对照者（非ＯＡ组）的关节液,采用酶联免疫吸附法（ＥＬＩＳＡ法）测定ＩＬ－１β,生物活性法（ＭＴＴ法）检测ＴＮＦ－α的水平。结果 在ＯＡ组关节滑液中,ＩＬ－１β的水平均显著高于对照组（Ｐ〈０．００１）,对照组的ＴＮＦ－α未能测出,而ＯＡ组ＴＮＦ－α的检出     

骨关节炎滑膜细胞分泌肿瘤坏死因子的生物学特征研究

目的 探讨滑液中肿瘤坏死因子（ｔｕｍｏｒ ｎｅｃｒｏｓｉｓ ｆａｃｔｏｒ－α,ＴＭＦ－α）生物活性及滑膜细胞分泌ＴＮＦ－α能力的变化在骨关节炎（ｏｓｔｅｏａｒｔｈｒｉｔｉｓ,ＯＡ）致病机制中的作用。方法 应用ＴＮＦ－α对Ｌ９２９细胞杀伤作用的比色法,检测并比较分析ＯＡ与不同年龄、不同形式关节内创伤时滑液和血清中ＴＮＦ－α生物活 ,以及培养的ＯＡ、急性关节内创伤和正常滑膜细胞自分泌及诱生性ＴＮＦ－α     

大承气颗粒剂和清胆灵对胆胰疾病所致全身性炎症反应的影响

目的：探讨大承气颗粒剂和清胆灵对胆胰疾病所致全身性炎症反应的影响。方法：对６６例急腹症病人进行前瞻性研究；将内毒素血症期、ＳＩＲＳ和ＭＯＤＳ患者分别按病种及ＡＰＡＣＨＥ－Ⅱ评分，分层随机分为综合安慰组和综合中药组，对后者根据病种使用大承气颗粒剂或清胆灵；动态观察血ＬＰＯ、ＴＮＦα、ＩＬ－６、内毒素等的变化。结果：内毒素血症期，综合中药组第１ｄＬＰＯ及第３ｄ内毒素降低，用清胆灵１ｄ后ＬＰＯ降低（Ｐ〈０．０５），第３ｄ有降低趋势；ＳＩＲＳ阶段，大承气颗粒剂或并用清胆灵于用药３、７ｄ能显著降低急性胰腺炎或胆道感染伴结石者ＬＰＯ、内毒素（Ｐ〈０．０５），第３ｄ大承气颗粒剂并清胆灵能降低胆道感染伴结石者ＩＬ－６、ＴＮＦα（Ｐ〈０．０５）；ＭＯＤＳ阶段，大承气颗粒剂用药３、７ｄ分别降低内毒素、ＴＮＦα（Ｐ〈０．０５）。结论     

骨关节炎滑液中肿瘤坏死因子α活性检测及滑膜组织超微结构观察

目的进一步探讨滑膜参与骨关节炎病理进程的机理。方法采用Ｌ９２９细胞毒活性法检测了２４例急、慢性关节内损伤及晚期骨关节炎（ＯＡ）患者关节滑液中肿瘤坏死因子（ＴＮＦ－α）生物活性，并用光镜和电镜观察比较三者滑膜组织间的形态学差异。结果ＯＡ滑液中所含ＴＮＦ－α水平较高；ＯＡ滑膜细胞性内膜，细胞增殖与脱落同时发生，内膜下层呈现明显的纤维增生性变、滑膜增厚；Ｂ型和Ａ型滑膜细胞的超微结构变化分别呈现旺盛的蛋白分泌相和活跃的吞噬功能。结论ＯＡ滑膜细胞的功能改变是其滑液中ＴＮＦ－α升高的原因之一；滑膜的变性既可受变性软骨产物的介导，又可导致ＯＡ的进展。     

地塞米松对创伤性急性肺损伤家兔肿瘤坏死因子-α的干预作用

目的 探讨地塞米松（Ｄｅｘ）对创伤性急性肺损伤（ＡＬＩ）治疗作用的可能机制。方法 采用逆转录聚合酶链反应（ＲＴ－ＰＣＲ）、酶联免疫吸附法（ＥＬＩＳＡ）检测２４只大耳白兔肺组织肿瘤坏死因子－α基因（ＴＮＦ－αｍＲＮＡ）表达及肺泡巨噬细胞（ＡＭ）培养上清液中肿瘤坏死因子－α（ＴＮＦ－α）、白细胞介素（ＩＬ）－６水平。结果 创伤性ＡＬＩ兔肺组织ＴＮＦ－αｍＲＮＡ表达及ＡＭ培养上清液中ＴＮＦ－α,ＩＬ－６含量较正常对照组比较明显升高（Ｐ〈０．０１）。Ｄｅｘ治疗后能显著下调ＴＮＦ－αｍＲＮＡ的表达（６８％,Ｐ〈０．０１）,降低ＡＭ分泌ＴＮＦ－α（Ｐ〈０．０５）及ＩＬ－６水平（Ｐ〈０．０１）。结论 Ｄｅｘ能缓解创伤性ＡＬＩ的发生、发展。其机制与其对ＴＮＦ－α、ＩＬ－６等炎性介质的调节作用密切相关。     

间皮细胞粘附分子表达对腹腔巨噬细胞功能的影响

目的通过研究细菌毒素和炎症细胞因子诱导的间皮细胞（ＭＣｓ）粘附分子表达及其对腹腔巨噬细胞功能的影响，探讨间皮细胞在腹膜抗菌防御中的作用。方法将体外培养的人腹膜间皮细胞以细菌脂多糖（ＬＰＳ）、ＴＮＦ－α或ＩＬ－１β刺激，采用间接免疫荧光染色技术，于激光扫描共聚焦显微镜下观察间皮细胞表面粘附分子（ＩＣＡＭ－１）的表达；采用细胞瑞氏染色方法，在普通光镜下计数腹腔巨噬细胞的粘附率。结果人腹膜间皮细胞表达ＩＣＡＭ－１，用ＬＰＳ、ＴＮＦ－α或ＩＬ－１β刺激间皮细胞后培养６小时，ＩＣＡＭ－１的表达高于对照组，有显著性差异（Ｐ＜０．０５）；各刺激组腹腔巨噬细胞的粘附率也明显高于对照组（Ｐ＜０．０５）。间皮细胞粘附分子的表达与腹腔巨噬细胞的粘附率呈正相关（ｒ＝０．９１８）。结论炎症介质和促炎症细胞因子通过刺激腹膜间皮细胞粘附分子表达增加，增强腹腔巨噬细胞的粘附和吞噬，在腹膜抗菌防御中起重要作用     

不同种类透析膜对单个核细胞激活产生细胞因子的影响

目的 了解不同种类透析膜对外周血单个核细胞（ＰＢＭＣ）产生白细胞介素－１β（ＩＬ－１β）、肿瘤坏死因子α（ＴＮＦα）、ＩＬ－６的影响。方法 分离培养ＰＢＭＣ，用放射免疫（ＲＩＡ）法测定培养上清液中ＩＬ－１β、ＴＮＦα、ＩＬ－６。结果 用铜仿（ＣＵ）膜透析，透前ＰＢＭＣ产生的ＩＬ－１β、ＴＮＦα、ＩＬ－６高于对照组；其次是聚甲基丙烯酸甲脂膜（ＰＭＭＡ）膜和ＨＥ膜。透析过程中ＰＢＭＣ产生的细胞因子都明     

一氧化氮对肺泡巨噬细胞致炎效应的调节作用

目的 探讨一氧化氮（ＮＯ）对肺泡巨噬细胞致炎效应的调节作用。方法 内毒素（ＬＰＳ）刺激体外培养的小鼠肺泡巨噬细胞,ＴＮＦα等细胞因子释放及ＮＯ对细胞因子释放的影响。结果ＬＰＳ诱导巨噬细胞释放炎症性细胞因子的时效关系不同,肺泡巨噬细胞释放ＴＢＦα、ＩＬ－１α、ＩＬ－６的峰值时间分别为６、８、２４小时。ＮＯ合成酶抑制剂甲基异硫脲明显降低ＬＰＳ诱导的ＮＯ释放,同时强烈刺激肺泡巨噬细胞释放ＩＬ－１β、ＩＬ     

心脏瓣膜置换术围术期动脉血及冠脉血TNF-α、SOD、LPO及CK-MB的变化

目的 观察进行体外循环（ＰＢ）病人围术期动脉血和冠脉血肿瘤坏死因子（ＴＮＦ－α）、超氧化物歧化酶（ＳＯＤ）、脂质过化物（ＬＰＯ）及肌酸激酶－ＭＢ（ＣＫ－ＭＢ）的变化。方法 １３例病人分别于ＣＰＢ前、升主动脉开放后５ｍｉｎ、３０ｍｉｎ、术毕、术后６ｈ、术后１８ｈ采集动脉和冠状窦血样本,测定血浆ＴＮＦα、ＬＰＯ的浓度及ＳＯＤ、ＣＫ－ＭＢ的活性和动脉血气,测算不同时间点的肺泡动脉氧分压差（ＰＡ－ａＤＯ２）,心肌ＴＮＦ－α的净释出量（冠状窦内血液ＴＮＦα含量减去动脉血含量）。结果 血液的ＴＮＦα水平在开放升主动脉后至术毕前明显增高（Ｐ〈０．０５）,ＣＰＢ期间心肌ＴＮＦα净释出量明显增高（Ｐ〈０．０５）;ＬＰＯ在开放升主动脉后明显升高且持续到术后６ｈ（Ｐ〈０．０５）,其峰值在开放升主动脉后５ｍｉｎ;ＳＯＤ含量逐渐下降并在     

大面积烧伤休克期切痂对全身炎症反应综合征的防治

目的 探讨休克期切痂对全身炎症反应综合征（ＳＩＲＳ）的作用。方法 临床观察８１例烧伤患者，根据切痂植皮的时间不同成分休克期切痂组（Ａ组）及非休克期切痂组（Ｂ组）。结果 Ｂ组术前及术后ＳＩＲＳ发生率均高于Ａ组（Ｐ〈０．０１），且切痂前、后血浆内毒素（ＬＰＳ）、肿瘤坏死因子（ＴＮＦ－α）、白介素－６（ＩＬ－６）及白介素－８（ＩＬ－８）含量居高不下，显著高于Ａ组（Ｐ〈０．０５￣０．０１），Ａ组ＳＩＲＳ并     

Measurement of the bioactivity of interleukin and tumour necrosis factor in synovial fluid of Kashin-Beck disease

We studied the bioactivity of interleukin (IL-1) and tumour necrosis factor (TNF) in the synovial fluid of 12 patients with Kashin-Beck disease (KBD), 8 patients with osteoarthritis (OA) and 8 normal controls. C57 female mouse T cell proliferation method was used to test the bioactivity of IL-1, and lethality method with L929 cells to test the bioactivity of TNF. The bioactivities of IL-1 and TNF in the synovial fluid from patients with KBD were higher than those in the synovial fluid of osteoarthritis and normal controls, indicating the participation of IL-1 and TNF in the pathogenesis of KBD.     

Elevated high-sensitivity C-reactive protein levels are associated with local inflammatory findings in patients with osteoarthritis

OBJECTIVE: C-reactive protein (CRP) has been associated with disease progression in patients with osteoarthritis (OA), but the reasons for this remain unclear. We hypothesized that higher CRP would be related to local inflammatory findings in the joints of patients with OA. METHODS: Plasma and synovial membrane specimens from 54 OA patients undergoing total hip or knee arthroplasty or arthroscopy were obtained. Synovial fluid was obtained from 25 of these patients. Hematoxylin and eosin stained synovial membrane sections were scored for degree of inflammatory cell infiltration. Plasma high-sensitivity CRP (hsCRP) levels, and serum and synovial fluid interleukin (IL)-6 and IL-1beta levels were measured by enzyme-linked immunosorbent assay. RESULTS: Fifty-seven percent of patients with idiopathic OA had inflammatory infiltrates within the synovial membrane. The mean hsCRP level in patients with inflammatory infiltrates was significantly higher than those without inflammation (4.7 +/- 5.0 mg/L vs 1.7 +/- 3.6 mg/L, P = 0.003). There were significant correlations between hsCRP levels and synovial fluid IL-6 (r = 0.64, P = 0.0006), degree of synovial inflammatory infiltration (r = 0.43, P = 0.002), and body mass index (r = 0.31, P = 0.02). Multivariate analysis indicated that only degree of inflammatory infiltrate was significantly associated with hsCRP level (P = 0.026). CONCLUSION: These results suggest that systemic hsCRP levels reflect synovial inflammation in OA patients, perhaps by means of synovial IL-6 production. Future studies are needed to clarify how these infiltrates and their products may contribute to disease pathogenesis.     

TGF-beta1 as a prognostic factor in the process of early osteoarthrosis in the rabbit knee

OBJECTIVE: To assess changes in knee joint fluid concentrations of transforming growth factor-beta1 (TGF-beta1) and proteoglycan (PG) fragments during the early course of post-traumatic osteoarthrosis (OA) after meniscectomy in the rabbit knee, and to ascertain whether the concentrations of these substances shortly after operation could be used as prognostic markers for the OA process. DESIGN: In 15 rabbits with medial meniscectomy in one knee and a sham operation in the other knee, synovial lavage fluid samples were taken repeatedly, before operation, every third week post-operatively until 12 weeks, thereafter every sixth week, and at death. Five rabbits each were killed at 13, 25 and 40 weeks. Synovial lavage fluid samples from five non-operated rabbits served as controls. At death, two histological scores were formed that characterized the highest (MAX) and the overall (ALL) degree of OA changes in each joint. RESULTS: TGF-beta1 and PG fragment concentrations in synovial lavage fluid correlated highly (R=0.81, P< 0.001). Both OA scores were higher in meniscectomized than controls (P< 0.05). The synovial lavage fluid concentration of TGF-beta1 at 3 weeks, but no other time point, correlated to the histological scores (ALL, R=0.58; MAX, R=0.52;P< 0.001). CONCLUSION: Higher concentrations of TGF-beta1 in synovial lavage fluid early after surgery seemed indicative for the later development of more severe OA changes in contrast to lower concentrations. The association between TGF-beta1 and the changes found later in the cartilage was underlined by the high correlations between this substance and PG fragment concentrations in synovial lavage fluid at all time points.     

Production of cartilage oligomeric matrix protein (COMP) by cultured human dermal and synovial fibroblasts

OBJECTIVE: Cartilage oligomeric matrix protein (COMP) is a large disulfide-linked pentameric protein. Each of its five subunits is approximately 100,000 Da in molecular weight. COMP was originally identified and characterized in cartilage and it has been considered a marker of cartilage metabolism because it is currently thought not to be present in other joint tissues, except for tendon. To confirm the tissue specificity of COMP expression we examined cultured human dermal fibroblasts, human foreskin fibroblasts, and normal human synovial cells for the synthesis of COMP in culture. METHOD: Normal synovial cells and normal human dermal foreskin fibroblasts were isolated from the corresponding tissues by sequential enzymatic digestions and cultured in media containing 10% fetal bovine serum until confluent. During the final 24 h of culture, the cells were labeled with 35S-methionine and 35S-cysteine in serum- and cysteine/methionine-free medium. The newly synthesized COMP molecules were immunoprecipitated from the culture media with a COMP-specific polyclonal antiserum, or with monoclonal antibodies or affinity-purified COMP antibodies. The immunoprecipitated COMP was analyzed by electrophoresis in 5.5% polyacrylamide gels. For other experiments, synovial cells cultured from the synovium of patients with rheumatoid arthritis (RA) and osteoarthritis (OA) were similarly examined. RESULTS: A comparison of the amounts of COMP produced by each cell type (corrected for the DNA content) revealed that synovial cells produced > or = 9 times more COMP than chondrocytes or dermal fibroblasts. COMP could be easily detected by immunoprecipitation in all cell types. Electrophoretic analysis revealed a distinct band with an apparent MW of 115-120 kDa in samples from each of the three cell types, regardless of the antibody used. COMP expression in cultures of synoviocytes derived from OA and RA patients showed that OA and RA synovial cells produced similar amounts of monomeric COMP of identical size to those COMP monomers produced by normal synovial cells. The addition of TGF-beta to these cultures resulted in an increase in COMP production in normal, OA and RA synovial cells (45, 116 and 115% respectively). CONCLUSION: These studies demonstrate that substantial amounts of COMP are produced by several mesenchymal cells including synoviocytes and dermal fibroblasts. These findings raise important concerns regarding the utility of measurements of COMP levels in serum or in synovial fluid as markers of articular cartilage degradation because of the likelihood that a substantial proportion of COMP or COMP fragments present in serum or synovial fluid may be produced by cells other than articular chondrocytes.     

Microarray analysis reveals the involvement of beta-2 microglobulin (B2M) in human osteoarthritis

OBJECTIVE: To assess whether beta-2 microglobulin (B2M) has effects on articular chondrocytes that would implicate B2M involvement in osteoarthritis (OA) pathogenesis. METHODS: The mRNA levels of B2M in fetal and osteoarthritic chondrocytes were detected by RT-PCR. B2M levels in synovial fluid and tissue cultured media from cartilage explants were tested using B2M ELISA kit. Primary cultured chondrocytes were used for proliferation and microarray experiments. RESULTS: The average B2M level in OA synovial fluid is significantly higher than that found in normal synovial fluid. However, there was no significant difference in B2M synovial fluid levels amongst differing OA stages. The release of B2M by osteoarthritic cartilage was detectable after 24h in culture and continued to increase during the 72 h study period. B2M had an inhibitory effect on chondrocyte growth at 1.0 microg/ml, and became significantly inhibitory at 10.0 microg/ml. Genes regulated by B2M were detected through microarray technology. Twenty genes were found to be up-regulated by B2M, including collagen type III which is known to be up-regulated in OA. Eleven genes were found to be down-regulated at least two-fold by B2M. CONCLUSION: These results indicate that B2M is highly expressed in OA cartilage and synovial fluid compared to normal, and suggest that B2M may have effects on chondrocyte function that could contribute to OA pathogenesis.Copyright 2002 OsteoArthritis Research Society International. Published by Elsevier Science Ltd.     

Low IGF-I in synovial fluid and serum in patients with aseptic prosthesis loosening

Background We have previously shown that proliferation in primary cultures of human osteoblast-like cells is lower after exposure to synovial fluid from patients with aseptic prosthesis loosening than after exposure to synovial fluid from patients with osteoarthrosis.

Materials and methods Insulin-like growth factors (IGF) I and II and IGF binding proteins (IGFBP) 3-6, were measured with radioimmunoassy in synovial fluid and in serum from patients with aseptic prosthesis loosening or osteoarthrosis. Proliferation in osteoblast-like MG-63 cells was studied with the CyQUANT assay.

Results IGF-I and IGFBP-4 concentrations were lower whereas the concentration of IGFBP-6 was higher in synovial fluids from patients with prosthesis loosening than in synovial fluid from patients with osteoarthrosis. IGF-I concentrations in serum from patients with prosthesis loosening were also lower than in the osteoarthrosis group, and were even below the normal range in most cases (72%). Synovial fluid from patients with aseptic loosening had a weaker stimulatory effect on MG63 osteoblast-like cell proliferation than synovial fluid from patients with osteoarthrosis, but there was no difference between the two groups when a human IGF-I antibody was added.

Interpretation Low levels of IGF-I in synovial fluid possibly result from low serum levelsand may be a mechanism leading to aseptic prosthesis loosening.     

Matrix metalloproteinase protein expression profiles cannot distinguish between normal and early osteoarthritic synovial fluid

ABSTRACT: BACKGROUND: Osteoarthritis (OA) and Rheumatoid arthritis (RA) are diseases which result in the degeneration of the joint surface articular cartilage. Matrix Metalloproteinases (MMPs) are enzymes that aid in the natural remodelling of tissues throughout the body including cartilage. However, some MMPs have been implicated in the progression of OA and RA as their expression levels and activation states can change dramatically with the onset of disease. Yet, it remains unknown if normal and arthritic joints demonstrate unique MMPs expression profiles, and if so, can the MMP expression profile be used to identify patients with early OA. In this study, the synovial fluid protein expression levels for MMPs 1, 2, 3, 7, 8, 9, 12 & 13, as well as those for the Tissue Inhibitors of MMPs (TIMPs) 1, 2, 3, & 4 were examined in highly characterized normal knee joints, and knee joints with clinically diagnosed OA (early and advanced) or RA. The purpose of this study was to determine if normal, OA, and RA patients exhibit unique expression profiles for a sub-set of MMPs, and if early OA patients have a unique MMP expression profile that could be used as an early diagnostic marker. METHODS: Synovial fluid was aspirated from stringently characterized normal knee joints, and in joints diagnosed with either OA (early and advanced) or RA. Multiplexing technology was employed to quantify protein expression levels for 8 MMPs and 4 TIMPs in the synovial fluid of 12 patients with early OA, 17 patients diagnosed with advanced OA, 15 with RA and 25 normal knee joints. Principle component analysis (PCA) was used to reveal which MMPs were most influential in the distinction between treatment groups. K - means clustering was used to verify the visual grouping of subjects via PCA. RESULTS: Significant differences in the expression levels of MMPs and TIMPs were observed between normal and arthritic synovial fluids (with the exception of MMP 12). PCA demonstrated that MMPs 2, 8 & 9 can be used to effectively separate individuals diagnosed with advanced arthritis from early osteoarthritic and normal individuals, however, these MMP profiles do not separate early OA from normal synovial fluid. An apparent separation between advanced OA and RA subjects was also revealed through PCA. K-means clustering verified the presence of 3 clusters: normal joints clustered with early OA, and separate clusters of advanced OA or RA. CONCLUSIONS: This study demonstrates that unique MMP and TIMP expression profiles are present within normal, advanced OA and RA synovial fluid. These MMP profiles can be used to distinguish advanced OA & RA synovial fluid from early OA & normal synovial fluid, and even between synovial fluid samples from OA and RA joints. Although this methodology cannot be used for the diagnosis of early OA, high throughput multiplex technology of MMPs and TIMPs in synovial fluid may prove useful in determining the severity of the disease state, and/or quantifying the response of individuals to disease interventions.     

Low IGF-I in synovial fluid and serum in patients with aseptic prosthesis loosening

Background We have previously shown that proliferation in primary cultures of human osteoblast-like cells is lower after exposure to synovial fluid from patients with aseptic prosthesis loosening than after exposure to synovial fluid from patients with osteoarthrosis.

Materials and methods Insulin-like growth factors (IGF) I and II and IGF binding proteins (IGFBP) 3–6, were measured with radioimmunoassy in synovial fluid and in serum from patients with aseptic prosthesis loosening or osteoarthrosis. Proliferation in osteoblast-like MG-63 cells was studied with the CyQUANT assay.

Results IGF-I and IGFBP-4 concentrations were lower whereas the concentration of IGFBP-6 was higher in synovial fluids from patients with prosthesis loosening than in synovial fluid from patients with osteoarthrosis. IGF-I concentrations in serum from patients with prosthesis loosening were also lower than in the osteoarthrosis group, and were even below the normal range in most cases (72%). Synovial fluid from patients with aseptic loosening had a weaker stimulatory effect on MG63 osteoblast-like cell proliferation than synovial fluid from patients with osteoarthrosis, but there was no difference between the two groups when a human IGF-I antibody was added.

Interpretation Low levels of IGF-I in synovial fluid possibly result from low serum levelsand may be a mechanism leading to aseptic prosthesis loosening.     

Joint fluid antioxidants are decreased in osteoarthritic joints compared to joints with macroscopically intact cartilage and subacute injury

OBJECTIVE: Excess reactive oxygen species and oxidative damage have been associated with the pathogenesis of osteoarthritis (OA). Extracellular superoxide dismutase (EC-SOD or SOD3) scavenges superoxide is the major catalytic antioxidant in joint fluid and is decreased in OA cartilage. We studied human joint fluid samples to test whether there is an association between OA and EC-SOD or other low molecular antioxidants in the joint fluid. METHODS: Joint fluid samples were obtained from 28 subjects with severe OA undergoing arthrocentesis or knee joint replacement and compared to joint fluid from 12 subjects undergoing knee arthroscopy for chronic knee pain, meniscal tears or anterior cruciate ligament reconstruction. EC-SOD protein was assayed by enzyme-linked immunosorbent assay (ELISA). Ascorbate and urate were measured with high performance liquid chromatography (HPLC) and total nitrates by the Greiss reaction. Glutathione (GSH) and oxidized glutathione were measured using a colorimetric method. Interleukin-6 (IL-6) and transforming growth factor-beta (TGF-beta) were both measured with ELISA. RESULTS: Human joint fluid contains significant amounts of the extracellular, catalytic antioxidant EC-SOD. Joint fluid from OA subjects is characterized by significantly decreased EC-SOD levels and significant decreases in GSH, and ascorbate compared to the reference group of knee joints with pain or subacute injury but macroscopically intact cartilage. GSH and ascorbate show only an age effect with no effect from disease state on regression modeling. Urate is present in joint fluid but does not show a significant difference between groups. IL-6 and TGF-beta both show non-significant trends to increases in the arthritic subjects. There was no correlation of EC-SOD levels with IL-6 as a marker of inflammation in either the comparison group or the OA group. CONCLUSIONS: EC-SOD, the major scavenger of reactive oxygen species (ROS) in extracellular spaces and fluids, is decreased in late stage OA joint fluid compared to fluid from injured/painful joints with intact cartilage. Injured joints may be able to increase or maintain secretion of EC-SOD but it appears that late stage OA joints fail to do so in spite of increased oxidative stress seen in the disease. Associated age related declines in GSH and ascorbate might also contribute to the development of severe OA. The net effect of these changes in joint fluid antioxidants is likely to accelerate the damaging oxidant effects on extracellular matrix stability in cartilage tissue.     

Prevalence and consequences of musculoskeletal symptoms in symphony orchestra musicians vary by gender: a cross-sectional study

Background

Tenascin-C (TN-C) is an extracellular matrix glycoprotein that is involved in tissue injury and repair processes. We analyzed TN-C expression in normal and osteoarthritic (OA) human cartilage, and evaluated its capacity to induce inflammatory and catabolic mediators in chondrocytes in vitro. The effect of TN-C on proteoglycan loss from articular cartilage in culture was also assessed.

Methods

TN-C in culture media, cartilage extracts, and synovial fluid of human and animal joints was quantified using a sandwich ELISA and/or analyzed by Western immunoblotting. mRNA expression of TN-C and aggrecanases were analyzed by Taqman assays. Human and bovine primary chondrocytes and/or explant culture systems were utilized to study TN-C induced inflammatory or catabolic mediators and proteoglycan loss. Total proteoglycan and aggrecanase -generated ARG-aggrecan fragments were quantified in human and rat synovial fluids by ELISA.

Results

TN-C protein and mRNA expression were significantly upregulated in OA cartilage with a concomitant elevation of TN-C levels in the synovial fluid of OA patients. IL-1 enhanced TN-C expression in articular cartilage. Addition of TN-C induced IL-6, PGE₂, and nitrate release and upregulated ADAMTS4 mRNA in cultured primary human and bovine chondrocytes. TN-C treatment resulted in an increased loss of proteoglycan from cartilage explants in culture. A correlation was observed between TN-C and aggrecanase generated ARG-aggrecan fragment levels in the synovial fluid of human OA joints and in the lavage of rat joints that underwent surgical induction of OA.

Conclusions

TN-C expression in the knee cartilage and TN-C levels measured in the synovial fluid are significantly enhanced in OA patients. Our findings suggest that the elevated levels of TN-C could induce inflammatory mediators and promote matrix degradation in OA joints.