The biological characteristics of a water soluble porphyrin in rat lymph nodes

The biological characteristics of a radiolabeled metalloporphyrin, 5,10,15,20-tetrakis(4-carboxyphenyl)-porphinato [ 67Cu]copper (II) ([ 67Cu]TCPP), in rat lymph nodes, surrounding muscle, fat and blood were determined. Lymphatic tissue localized greater amounts of [ 67Cu]TCPP than did surrounding muscle and fat. Inflamed lymph nodes localized greater amounts of [ 67Cu]TCPP than did noninflamed lymph nodes. Time course studies suggest that the uptake of [ 67Cu]TCPP in noninflamed and in inflamed lymph nodes may involve different biological processes. The affinity of [ 67Cu]TCPP for inflamed lymph nodes may be influenced by the degree of inflammation. If further studies confirm these results, [ 67Cu]TCPP may be useful as a potential radiopharmaceutical for imaging inflamed lymph nodes.