Effects of antiinflammatory drugs on arthritic cartilage: a high-frequency quantitative ultrasound study in rats.
OBJECTIVE
To evaluate the ability of 55-MHz quantitative ultrasound (US) to detect the in vivo effects of experimental arthritis, as well as those of two antiinflammatory drugs, naproxen (NPX) and dexamethasone (DEX), on cartilage and subchondral bone.


METHODS
Arthritis was induced in both knees of 108 rats by intraarticular injection of zymosan (ZYM). Two groups of arthritic rats (n = 36 per group) were treated daily with either NPX (10 mg/kg/day) or DEX (0.1 mg/kg/day). Using a 3-dimensional US microscope, patellae were explored in vitro on days 5, 14, and 21 after injections. US assessment included the analysis of quantitative indices of local modifications involving cartilage and bone: integrated reflection coefficient (IRC) from the cartilage surface and apparent integrated backscatter from the cartilage internal structure (cartilage matrix) (AIB(cartilage)) and the cartilage-bone interface (AIB(bone)).


RESULTS
ZYM induced articular surface fibrillation that resulted in a decrease in IRC at all times (P < 0.02) and in an increase in AIB(bone) on days 5 and 14 (P < 0.005). Fibrillation was not changed by NPX administration, while it disappeared following DEX treatment. Cartilage-bone interface alterations were prevented by DEX and partially compensated for by NPX. Cartilage matrix echogenicity decreased with time in all groups due to maturation (P < 0.05), except in DEX-treated rats.


CONCLUSIONS
Quantitative 55 MHz US allowed detection of early cartilage and bone lesions due to experimental arthritis, and also allowed detection of the effects of antiinflammatory drugs. NPX seemed to have an effect on subchondral bone lesions, but not on cartilage. DEX appeared to repair articular surface and bone, but prevented animal growth and cartilage maturation.
Jaffré
Britta
B
LIP, Unité Mixte de Recherches (UMR) 7623 CNRS-Université Paris VI, Paris, France.
Watrin
Astrid
A
Loeuille
Damien
D
Gillet
Pierre
P
Netter
Patrick
P
Laugier
Pascal
P
Saïed
Amena
A
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D001169:Arthritis, Experimental / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D002358:Cartilage, Articular / Q000000981:diagnostic imaging*; D003907:Dexamethasone / Q000627:therapeutic use*; D004195:Disease Models, Animal; D008297:Male; D009288:Naproxen / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D014463:Ultrasonography
D000893:Anti-Inflammatory Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D009288:Naproxen; D003907:Dexamethasone