Methotrexate-induced accumulation of fluorescent annexin V in collagen-induced arthritis

Mol Imaging. 2005 Jan-Mar;4(1):1-6. doi: 10.1162/15353500200504142.


We examined the accumulation of Cy5.5-labeled annexin V in the paws of mice with and without collagen-induced arthritis, with and without methotrexate (MTX) treatment, by near-infrared fluorescence imaging. Fluorescence reflectance imaging (FRI) of paws was performed 48 hr after MTX injection and at 10 min and 3 hr after the injection of Cy5.5-annexin V (1 nmol dye per mouse). With arthritic paws, MTX treatment caused a 7-fold increase in fluorescence intensity compared with the paws of untreated mice and a 4-fold increase compared to nonarthritic paws of MTX-treated mice (p < .001 each). Tissue samples of paws were examined histologically for Cy5.5 fluorescence and by TUNEL staining for apoptosis. Cy5.5-annexin V was seen in the hyperplastic synovia of MTX-treated mice, and TUNEL staining for apoptosis showed apoptotic cells in the hyperplastic synovia. Monitoring the uptake of Cy5.5-annexin V in arthritic paws by FRI provided a method of assessing a response to MTX, a response that was readily quantitated with simple instrumentation and that occurred before conventional measurements of treatment response.

MeSH terms

  • Animals
  • Annexin A5 / drug effects
  • Annexin A5 / metabolism*
  • Antirheumatic Agents / pharmacology*
  • Arthritis, Experimental / drug therapy
  • Arthritis, Experimental / metabolism*
  • Arthritis, Experimental / pathology
  • Carbocyanines / metabolism
  • Collagen / toxicity
  • Fluorescent Dyes / metabolism
  • Joints / drug effects
  • Joints / metabolism
  • Joints / pathology
  • Male
  • Methotrexate / pharmacology*
  • Mice
  • Mice, Inbred DBA
  • Molecular Biology / methods
  • Synovial Fluid / metabolism


  • Annexin A5
  • Antirheumatic Agents
  • CY5.5 cyanine dye
  • Carbocyanines
  • Fluorescent Dyes
  • Collagen
  • Methotrexate