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Macrophage infiltration into the rat knee detected by MRI in a model of antigen‐induced arthritis
Author(s) -
Beckmann Nicolau,
Falk Regina,
Zurbrügg Stefan,
Dawson Janet,
Engelhardt Petra
Publication year - 2003
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.10480
Subject(s) - infiltration (hvac) , medicine , magnetic resonance imaging , arthritis , dexamethasone , antigen , pathology , rheumatoid arthritis , cartilage , immunology , anatomy , radiology , physics , thermodynamics
Three‐dimensional (3D) MR images were obtained from the knees of rats in a model of antigen‐induced arthritis, elicited by the intraarticular administration of methylated bovine serum albumin (mBSA) to previously immunized rats. Superparamagnetic particles of iron oxide (SPIO) were administered i.v. 24 hr before each imaging session. Starting 4 days postantigen injection, images from arthritic knees exhibited distinctive signal attenuation in the synovium. This signal attenuation was significantly smaller in knees from animals treated with dexamethasone, a glucocorticosteroid, and completely absent in contralateral knees that had been challenged with vehicle. A significant negative correlation was found between the MRI signal intensity in the synovium and the histologically determined iron content in macrophages located in the same region. These results suggest the feasibility of detecting macrophage infiltration into the knee synovium in this model of antigen‐induced arthritis by labeling the cells with SPIO. This readout could provide an early marker of disease progression, before more aggressive changes like cartilage and bone erosion take place. Monitoring early changes associated with arthritis can have an impact in preclinical studies by shortening the duration of the experimental period and by facilitating the investigation of novel immunomodulatory therapies acting on macrophages. Also, the approach can be potentially adapted to clinical studies. Magn Reson Med 49:1047–1055, 2003. © 2003 Wiley‐Liss, Inc.