Quantitative analysis of NF-kappaB-expression in cartilage and synovium of rat knee induced by intra-articular injection of synthetic lipid A.
OBJECTIVE
NF-kappaB expression in cartilage and synovium of rat knee after intra-articular injection of lipid A was investigated.


METHODS
Inflammation was evaluated in histological sections stained with hematoxylin and eosin, toluidine blue and immunostained with monoclonal anti-NF-kappaB antibody or monoclonal anti-TNF-alpha antibody.


RESULTS
Inflammatory cell infiltration into the synovium, hyperplasia of synovial lining layers, loss of metachromasia of cartilage, TNF-alpha-positive cells and NF-kappaB-positive cells in the synovium and cartilage were observed in all 26 rat knees intra-articularly injected with lipid A. The numbers of TNF-alpha-positive and NF-kappaB-positive synovial cells and chondrocytes after the injection were significantly greater than those in knees injected with triethylamine (p < 0.05). The amount of inflammatory cell infiltration into the synovium, synovial lining layers, TNF-alpha-positive synovial cells and NF-kappaB-positive synovial cells 12 h after the injection was significantly smaller than those after 1 day (p < 0.05).


CONCLUSIONS
Intra-articular injection of lipid A induced NF-kappaB expression in cartilage and synovium. Cartilage degeneration started earlier than synovitis in this model. Quantitative analysis of NF-kappaB in cartilage might be useful to evaluate the extreme acute phase of cartilage degeneration.
Tanimoto
M
M
macopp@ppp.bekkoame.ne.jp
Koshino
T
T
Takagi
T
T
Hayashi
T
T
Saito
T
T
D000818:Animals; D001169:Arthritis, Experimental / Q000139:chemically induced / Q000473:pathology; D002358:Cartilage, Articular / Q000737:chemistry / Q000378:metabolism*; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism; D007150:Immunohistochemistry; D007270:Injections, Intra-Articular; D007596:Joints / Q000737:chemistry / Q000378:metabolism*; D008050:Lipid A / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D016328:NF-kappa B / Q000032:analysis / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D013583:Synovial Membrane / Q000737:chemistry / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D008050:Lipid A; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha