Abstract： Objective To observe the influence of intra-articular injection of lovastatin on cartilage degeneration and mRNA expres-sion of matrix metalloproteiase-1,-3 (MMP-1,-3) in cartilage and synovium of osteoarthritis (OA) model. Methods Thirty New Zeal-and rabbits underwent unilateral anterior cruciate ligament transection (ACLT) were random divided into two groups. The rabbits in experi-mental group received 0.1 mg/ml intra-articular lovastatin injection at 0.2 ml/kg of body weight immediately after surgery , once a week. Those in control group were treated with intra-articular injection of normal saline. At the 6th week after surgery, all rabbits were sacrificed. The articular cartilage degeneration of medial femoral condyle was evaluated under microscopy. Gene expression of MMP-1,-3 was detected by reverse transcription-polymerase chain reaction (RT-PCR). Results Cartilage degeneration in untreated group was significantly more severe than that in experimental group. In cartilage, no significant difference on the expression of MMP-1 and MMP-3 mRNA was found be-tween the experimental group and control group. In synovium, the expression of MMP-1 and MMP-3 mRNA was significantly suppressed in experimental group compared with control group. Conclusion During the development of experimental OA, intra-articular administration of lovastatin reduces the expression of matrix degrading enzyme, thus alleviate cartilage degradation.