OBJECTIVETo investigate the protective effect of LR-90 on articular cartilage in rabbit model of osteoarthritis.

METHODSThe cultured rabbits chondrocytes were assigned to be treated with IL-1β (10ng/ml) or IL-1β (10ng/ml)+LR-90 (50 mg/L). The mRNA expression of MMP-13, ADAMTS-5, aggrecan and collagen II in chondrocytes were assessed by real-time quantitative reverse transcription polymerase chain reaction (RT-PCR). Twenty male New Zealand white rabbits underwent bilateral anterior cruciate ligament transection (ACLT) to establish a animal model of osteoarthritis. Four weeks after model established, on the basis of randomization one knee of each rabbit was treated with 50 mg/L LR-90 in normal saline (NS) (experimental group) and the other knee was treated with same volume of NS (control group), 1/week × 5. Nine weeks after ACLT all rabbits were sacrificed and the knee joints were evaluated by gross morphology and histology. The mRNA expression of IL-1β, MMP-13, ADAMTS-5, aggrecan and collagen Ⅱ in articular cartilage was analyzed by RT-PCR.

RESULTSGross morphology and Mankin histological evaluation showed that the extent and grade of cartilage damage in the experimental group were less severe than those in the control group.Compared to IL-1β group, LR-90 treatment suppressed the mRNA expression of MMP-13 and ADAMTS-5, and enhanced aggrecan and collagen Ⅱ mRNA expression. Consistent with the in vitro results, the intraarticular LR-90 administration suppressed the mRNA expression of IL-1β,MMP-13 and ADAMTS-5 (all P<0.01), while enhanced mRNA expression of aggrecan and collagen Ⅱ in cartilage (all P<0.01).

CONCLUSIONLR-90 protects against cartilage degradation and inhibits the progression of osteoarthritis in rabbit mode1 of osteoarthritis, which is associated with the suppressing IL-1β, MMP-13, ADAMTS-5 and promoting aggrecan and collagen Ⅱ mRNA expression in cartilage.