leukotriene-b4 and Joint-Diseases

Platelet-activating factor (PAF) and its receptor (PAFR) have been shown to be involved in several inflammatory events, including neutrophil chemoattraction and nociception. The present study addressed the role of PAF in the genesis of articular hyperalgesia in a model of joint inflammation. Zymosan-induced articular hyperalgesia, oedema and neutrophil migration were dose-dependently reduced following pretreatment with selective PAFR antagonists, UK74505 (5, 10 and 20 mg/kg) and PCA4248 (3, 10, 30 mg/kg). These parameters were also reduced in PAF receptor-deficient mice (PAFR(-/-)). The hyperalgesic action of PAF was further confirmed by the demonstration that joint injection of PAF induces a dose- (0.3, 1 and 3 μg/joint), time- and PAFR-dependent articular hyperalgesia and oedema. The PAF hyperalgesic mechanisms were dependent on prostaglandins, leukotrienes and neutrophils, as PAF-induced articular hyperalgesia was inhibited by indomethacin (COX inhibitor), MK886 (leukotrienes synthesis inhibitor) or fucoidan (leukocyte rolling inhibitor). Furthermore, PAF-induced hyperalgesia was reduced in 5-lypoxigenase-null mice. In corroboration of these findings, intra-articular injection of PAF promotes the production of LTB(4) as well as the recruitment of neutrophils to the joint. These results suggest that PAF may participate in the cascade of events involved in the genesis of articular inflammatory hyperalgesia via stimulation of prostaglandins, leukotrienes and neutrophil migration. Finally, targeting PAF action (e.g., with a PAFR antagonist) might provide a useful therapeutic approach to inhibit articular inflammatory hyperalgesia.

Topics: Animals; Dihydropyridines; Disease Models, Animal; Dose-Response Relationship, Drug; Hyperalgesia; Imidazoles; Immune System Diseases; Inflammation; Joint Diseases; Leukocyte Disorders; Leukotriene B4; Male; Mice; Mice, Inbred BALB C; Mice, Knockout; Neutrophils; Platelet Activating Factor; Platelet Membrane Glycoproteins; Prostaglandins; Receptors, G-Protein-Coupled; Time Factors; Zymosan

Although alterations in biomarkers of cartilage turnover in synovial fluid (SF) have been demonstrated in horses with osteochondrosis (OC), there have been few investigations of such alterations in animals <1 year old. In this study tarsocrural SF samples from foals aged 18, 22 and 52 weeks of age were assessed for: (1) 'turnover' biomarkers of type II collagen (CPII and C2C) and proteoglycan (CS846 and glycosaminoglycans [GAG]); (2) matrix metalloproteinase (MMP) activity; (3) insulin-like growth factor (IGF)-1; (4) transforming growth factor (TGF)-β1; (5) prostaglandin (PG) E(2); and (6) leukotriene B(4). Using a linear mixed model, the concentration of biomarkers was compared between animals that developed or did not develop radiographic evidence of OC at 24 or 48 weeks of age. The CPII:C2C ratio tended to be higher in OC-affected joints compared to controls at all ages, and this difference was statistically significant at 22 weeks of age. The concentrations of CS846 and IGF-1, and the CS846:GAG ratio were reduced in OC-affected joints relative to controls at 18 weeks of age only. At 52 weeks of age, the PGE(2) concentration was lower in joints with OC. Overall, there appears to be a consistent anabolic shift in type II collagen turnover in juvenile joints affected by OC. Aberrant proteoglycan turnover is not a hallmark of the late repair of this lesion but reduced concentrations of IGF-1 in SF may be associated with early-stage lesions.

Topics: Age Factors; Animals; Biomarkers; Collagen Type II; Female; Glycosaminoglycans; Horse Diseases; Horses; Insulin-Like Growth Factor I; Joint Diseases; Leukotriene B4; Male; Matrix Metalloproteinases; Osteochondrosis; Prostaglandins; Proteoglycans; Radiography; Synovial Fluid; Tarsal Joints; Transforming Growth Factor beta

Clinical and experimental evidence suggests that arachidonic acid metabolism through lipoxygenase and cyclooxygenase pathways may play an important role in the pathogenesis of both inflammatory and degenerative joint diseases. The aim of the present paper was to measure the levels of different arachidonate metabolites in arthrosis or rheumatoid joint effusions.. We studied synovial fluids from 22 patients with arthrosis and 8 patients with rheumatoid arthritis. The levels of TxB2, 6-keto-PGF1 alpha LTB4 and LTC4 were measured by radioimmunoassay.. The levels of the different arachidonate metabolites were higher in patients with rheumatoid arthritis than in those with arthrosis and the differences were always statistically significant, except for TxB2 values. Furthermore, in patients with arthrosis the levels of such metabolites were not significantly correlated with one another, with the exception of LTB4 and LTC4 values, while in patients with rheumatoid arthritis these levels were directly and significantly correlated.. In inflammatory joint disease levels of arachidonate metabolites are higher and more directly correlated with one another than in degenerative joint disease. Our data may explain the better efficacy of non-steroidal anti-inflammatory drugs in patients with arthrosis than in those with rheumatoid arthritis and the frequent necessity for steroidal treatment in this last condition.

Topics: 6-Ketoprostaglandin F1 alpha; Arachidonic Acid; Arthritis, Rheumatoid; Humans; Joint Diseases; Leukotriene B4; Leukotriene C4; Radioimmunoassay; Synovial Fluid; Thromboxane B2