Protective effect of lentivirus-mediated siRNA targeting ADAMTS-5 on cartilage degradation in a rat model of osteoarthritis

The etiology of osteoarthritis (OA) is complex and multifaceted. Osteoarthritis is a chronic and progressive disease of the joints that is characterized by the degradation of articular cartilage. A disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5) is the major aggrecanase in cartilage. The aim of this study was to evaluate the effect of ADAMTS-5 knockdown on cartilage degradation. Rat articular chondrocytes were transfected with lentivirus-mediated ADAMTS-5 small interfering RNA (siRNA) or with empty vector control plasmid DNA (as the control). The suppression efficiency was measured using real-time polymerase chain reaction (RT-PCR) and western blot analysis. We then selected the most effective siRNA (siRNA1) and constructed the lentivirus-mediated siRNA targeting ADAMTS-5 for stable transfection. An animal model of OA was created using male Sprague-Dawley rats. OA was induced by performing anterior cruciate ligament transection (ACL-T) and partial medial meniscectomy (PM). The animals (n=80, weight 250-300 g) received an intra-articular injection of the empty vector control plasmid DNA or lentivirus-mediated ADAMTS-5 siRNA1 (20 mu l, 1x10(8) TU/ml). The progression of OA was analyzed using Osteoarthritis Research Society International (OARSI) scores. Compared with the control, ADAMTS-5 gene expression was decreased by approximately 80% by siRNA1 in a monolayer culture of chondrocytes. The intra-articular injection of lentivirus-mediated ADAMTS-5 siRNA1 in vivo resulted in the downregulation of ADAMTS-5 protein expression and improved OARSI scores (p<0.05). A single injection of lentivirus-mediated ADAMTS-5 siRNA prevented the degradation of articular cartilage. This method may provide a novel therapeutic strategy for the treatment of human OA.