Optical imaging of experimental arthritis using allogeneic leukocytes labeled with a near-infrared fluorescent probe

Eur J Nucl Med Mol Imaging. 2006 Sep;33(9):998-1006. doi: 10.1007/s00259-006-0081-y. Epub 2006 Jun 13.

Abstract

Purpose: The purpose of this study was to assess the feasibility of inflammation detection in an antigen-induced arthritis model using fluorescent leukocytes and optical imaging.

Methods: Antigen-mediated monoarthritis was induced in the right knee of 12 Sprague-Dawley rats. Six rats remained untreated and six rats were treated with cortisone. All rats received ex vivo fluorescent-labeled rat leukocytes. Optical images of both knees were acquired before and at 5 min, 1 h, 4 h, and 24 h after cell injection. Images were evaluated qualitatively and quantitatively by calculating signal intensity ratios between the right arthritic (A) and contralateral normal (N) knee. A/N ratios were tested for significant differences between baseline values and values after cell injection using a paired t test as well as between the untreated and cortisone-treated group using an unpaired t test. Synovial specimens were processed and evaluated for labeled cells with fluorescence microscopy.

Results: At 4 h and 24 h p.i., the A/N ratios of untreated arthritic knees showed a significant signal increase compared with baseline values (p<0.05) and a significant difference compared with A/N ratios of cortisone-treated animals (p<0.05). Fluorescent microscopy confirmed the presence of labeled cells in the arthritic synovium.

Conclusion: Inflammation in antigen-induced arthritis can be detected with ex vivo labeled allogenic leukocytes and optical imaging.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arthritis, Experimental / diagnosis*
  • Arthritis, Experimental / immunology
  • Arthritis, Experimental / pathology
  • Female
  • Fluorescent Dyes*
  • Image Processing, Computer-Assisted
  • In Vitro Techniques
  • Isoantigens
  • Leukocytes / immunology
  • Microscopy, Fluorescence / methods
  • Optics and Photonics
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Fluorescent Dyes
  • Isoantigens