The effect of dexamethasone on the expression of activated NF-kappa B in adjuvant arthritis.
The transcription factor NF-kappa B plays a significant role in inflammatory diseases. In this study we have investigated the expression of activated NF-kappa B p65 subunit in the rat adjuvant arthritis model in a 28-day time-course experiment using immunohistochemistry. The expression of p65 was detected in the synovial lining layer and around the blood vessels in the inflamed synovium as early as Day 3 post-adjuvant injection. The cells that expressed p65 in the synovial lining were thought to be macrophage-like synoviocytes. The expression was stronger in the injected hindpaw than that in the noninjected hindpaw. Dexamethasone treatment at 1 mg/kg p.o. (Days 0-20) suppressed both the hindpaw edema and increase in p65 expression. Withdrawal of the treatment caused increases in both p65 expression and paw volume. Together these suggest that activated NF-kappa B was specifically expressed in the arthritic synovium and may play a significant role in the development of arthritis.
Tsao
P W
PW
Department of Inflammatory Diseases, Tanabe Seiyaku Co. Ltd., Saitama, Japan.
Suzuki
T
T
Totsuka
R
R
Murata
T
T
Takagi
T
T
Ohmachi
Y
Y
Fujimura
H
H
Takata
I
I
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001169:Arthritis, Experimental / Q000378:metabolism*; D003907:Dexamethasone / Q000494:pharmacology*; D005260:Female; D007150:Immunohistochemistry; D016328:NF-kappa B / Q000096:biosynthesis*; D051381:Rats; D011917:Rats, Inbred Lew
D000893:Anti-Inflammatory Agents; D016328:NF-kappa B; D003907:Dexamethasone