 |
|
|
 |
Reduction of Tumor Necrosis Factor Induced Nuclear Factor-kB Nuclear Translocation and DNA Binding by Dexamethasone in Human Osteoarthritic Synovial Tissue Explants THOMAS LEHMANN, CHRISTIAN MURPHY, DAVID G. ZAHRA, and MALCOLM L. HANDEL
ABSTRACT.
Methods. Explants of synovial tissue from patients undergoing joint replacement surgery for arthritis were placed in culture and treated with dexamethasone 10-6 M for 18 h and again at 30 min prior to stimulation with TNF for a further 30 min. NF-kB and AP-1 DNA binding activities were determined by electrophoretic mobility shift analysis of nuclear extracts prepared from 6 whole tissue explants. Nuclear localization of NF-kB was determined by quantitative immunohistochemistry for Rel-A(p65) in thin sections of 5 synovial tissue explants. Results. TNF induced NF-kB nuclear translocation and DNA binding in all OA synovial tissue explants, although there were no consistent effects on AP-1 DNA binding. Dexamethasone reduced TNF stimulated nuclear translocation of RelA(p65) in all 5 OA synovial explants analyzed by immunohistochemistry. Dexamethasone partially decreased NF-kB DNA binding in 5 of 6 TNF stimulated explants and 4 of 6 unstimulated explants. In cultured rheumatoid arthritis and OA fibroblast-like synoviocytes and Mono Mac 6 cells the effects of dexamethasone on NF-kB DNA binding were not evident. Conclusion. Dexamethasone partially inhibits TNF induced NF-kB DNA binding in human synovial tissue. It is feasible to use explants of intact fresh human synovium as a substrate for the action of antirheumatic drugs targeting a transcription factor. (J Rheumatol 2002;29:787-95) Key Indexing Terms:
NUCLEAR FACTOR-kB
|