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International Journal of Inflammation
Volume 2011, Article ID 691587, 6 pages
http://dx.doi.org/10.4061/2011/691587
Research Article

MMP-Activated Fluorescence Imaging Detects Early Joint Inflammation in Collagen-Antibody-Induced Arthritis in CC-Chemokine Receptor-2-Null Mice, In-Vivo

1Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900, USA
2Veterans Administration Center for Research on AIDS and HIV-1 Infection and South Texas Veterans Health Care System, Audie L. Murphy Division, San Antonio, TX, USA

Received 8 February 2011; Revised 12 March 2011; Accepted 18 March 2011

Academic Editor: Bernhard Rintelen

Copyright © 2011 Jessica M. Ibarra et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The Standard measures of experimental arthritis fail to detect, visualize, and quantify early inflammation and disease activity. Here, we describe the use of an injectable MMP-activated fluorescence agent for in vivo quantification of acute inflammation produced by collagen-antibody-induced arthritis (CAIA) in CC chemokine receptor-2 (Ccr2−/−) null mice. Although Ccr2−/− DBA1/J mice were highly susceptible to and rapidly developed CAIA, the standard clinical assessment of fore or hind paw thicknesses was unable to detect significant acute inflammatory changes (days 3–10). Remarkably, noninvasive, in situ, MMP-activatable fluorescent imaging of Ccr2−/− DBA1/J mice with CAIA displayed acute joint pathology in advance of clinically measurable acute inflammation (days 5, 7, and 10). These results were confirmed by the histology of ankle joints, which showed significant inflammation, bone loss, and synovial hyperplasia, compared to control mice at postimmunization day 5. The MMP-mediated fluorescence technique holds tremendous implications for quantifiable examination of arthritis disease activity of acute joint inflammation.