SUMMARYBiomarker quantification in disease tissues from animal models of rheumatoid arthritis (RA) can help to provide insights into the mechanisms of action of novel therapeutic agents. In this study we validated the kinetics of IL-1 b , TNF-a and IL-6 mRNA and protein expression levels in joints from DBA/ 1OlaHsd murine collagen-induced arthritis (CIA) and Lewis rat Streptococcal cell wall (SCW)-induced arthritis by real-time polymerase chain reaction (PCR) TaqMan® and Enzyme-linked immunosorbent assay (ELISA). Prednisolone was used as a reference to investigate any correlation between clinical response and cytokine levels at selected time-points. To our knowledge this is the first report showing a close pattern of expression between mRNA and protein for IL-1 b and IL-6, but not for TNF-a , in these two models of RA. The kinetics of expression for these biomarkers suggested that the optimal sampling time-points to study the effect of compounds on both inflammation and cytokine levels were day 4 postonset in CIA and day 3 after i.v challenge in SCW-induced arthritis. Prednisolone reduced joint swelling through a mechanism associated with a reduction in IL-1 b and IL-6 protein and mRNA expression levels. At the investigated time points, protein levels for TNF-a in arthritic joints were lower than the lower limit of detection of the ELISA, whereas mRNA levels for this cytokine were reliably detected. These observations suggest that RT-PCR TaqMan® is a sensitive technique that can be successfully applied to the quantification of mRNA levels in rodent joints from experimental arthritis models providing insights into mechanisms of action of novel anti-inflammatory drugs.Keywords animal models mice rats collagen-induced arthritis SCW-induced arthritis cytokines interleukins prednisolone

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Objective Oncostatin M (OSM) is a member of the interleukin‐6 cytokine family, with well‐documented effects on cell growth and differentiation. OSM also has proinflammatory and cartilage degradative properties. The aim of this study was to investigate the significance of OSM in arthritis pathology using a neutralizing antibody in arthritis models. Methods Collagen‐induced arthritis (CIA) was established in male DBA/1 mice. Reverse transcriptase–polymerase chain reaction was used to detect OSM messenger RNA (mRNA) message levels in arthritic joints. Neutralizing anti‐OSM antibody or control immunoglobulin was administered on days 1 and 3 after disease onset. Animals were assessed for clinical arthritis for 2 weeks, followed by a histologic analysis of paws. Pristane‐induced arthritis (PIA) was produced in male CBA mice dosed with anti‐OSM or control immunoglobulin immediately before disease onset. Mice with PIA were assessed for clinical arthritis over a period of 100 days. Results Levels of mRNA for OSM, but not GAPDH, were elevated in arthritic joints of mice with CIA compared with those of normal controls. Mice with CIA treated with anti‐OSM antibody showed significant amelioration of both the clinical severity (P < 0.01) and the number of affected paws (P < 0.01) compared with control animals. Histologic analysis confirmed these clinical findings, revealing a marked reduction in cellular infiltration of synovium and cartilage damage. In the PIA model, the incidence of arthritis was 65% in the control group compared with 0% in the anti‐OSM–treated animals. Conclusion These results demonstrate a key role for endogenously produced OSM as a potent mediator of joint pathology, and suggest that OSM might be a potentially important, novel therapeutic target for treatment of established rheumatoid arthritis.

The preparation and topical antiinflammatory potencies of a series of halomethyl 17 alpha-(acyloxy)- 11 beta-hydroxy-3-oxoandrosta-1,4-diene-17 beta-carbothioates, carrying combinations of 6 alpha-fluoro, 9 alpha-fluoro, 16-methyl, and 16-methylene substituents, are described. Key synthetic stages were the preparation of carbothioic acids and their reaction with dihalomethanes. The carbothioic acids were formed from 17 beta-carboxylic acids by initial reaction with dimethylthiocarbamoyl chloride followed by aminolysis of the resulting rearranged mixed anhydride with diethylamine, or by carboxyl activation with 1,1'-carbonyldiimidazole (CDI) or 2-fluoro-N-methylpyridinium tosylate (FMPT) and reaction with hydrogen sulfide, the choice of reagent being governed by the 17 alpha-substituent. Carboxyl activation with FMPT and reaction with sodium hydrogen selenide led to the halomethyl 16-methyleneandrostane-17 beta-carboselenoate analogues. Anti-inflammatory potencies were measured in humans using the vasoconstriction assay and in rats and mice by a modification the Tonelli croton oil ear assay. Best activities were shown by fluoromethyl and chloromethyl carbothioates with a 17 alpha-propionyloxy group. S-Fluoromethyl 6 alpha, 9 alpha-difluoro-11 beta-hydroxy-16 alpha-methyl-3-oxo-17 alpha- (propionyloxy)androsta-1,4-diene-17 beta-carbothioate (fluticasone propionate, FP) was selected for clinical study as it showed high topical antiinflammatory activity but caused little hypothalamic-pituitary-adrenal suppression after topical or oral administration to rodents.