The Effect and Mechanism of Continuous Passive Exercise Combined with Platelet-Rich Plasma on Rabbit Knee Osteoarthritis Model

Osteoarthritis (OA) is a disease in orthopedics. Continuous passive exercise (CPM) and intra-articular injection of platelet-rich plasma (PRP) have certain effects on OA. However, the effect of these two combination on OA remains unclear. The present study aims to evaluate the treatment efficacy of this combination on OA. 50 New Zealand white rabbits were randomly divided into control group, OA group, CPM group, PRP group and CPM+ PRP group followed by analysis of the pathological changes of chondrocyte by H&E staining and Mankin's score, level of IL-1 and TNF-alpha by ELISA, as well as MMP-1 and MMP-13 protein expression by western blot. Compared with control group, the Mankin's score of OA group was significantly increased (P < 0.05), along with increased expressions of MMP-1 and MMP-13 in the joint fluid, levels of IL-1 and TNF-alpha (P < 0.05). CPM group and PRP group presented significantly lower Mankin's scores, reduced IL-1 and TNF-alpha levels in synovial fluid as well as decreased MMP-1 and MMP-13 protein expression in articular cartilage compared with OA group (P < 0.05). Compared with CPM group and PRP group, the Mankin's score of CPM+ PRP group was significantly decreased (P < 0.05), along with reduced IL-1 and TNF-alpha levels in joint fluid, and decreased expression of MMP-1 and MMP-13 protein in articular cartilage (P < 0.05). The efficacy of CPM combined with PRP in treating OA is better than that of CPM or PRP alone, which may be related to the decreased expression of IL-1, TNF-alpha, MMP-1 and MMP-13.