Platelet-rich plasma combined with ozone prevents cartilage destruction and improves weight-bearing asymmetry in a surgery-induced osteoarthritis rabbit model.

BACKGROUND Osteoarthritis (OA) is the most common degenerative disease in older adults and its treatment remains unsatisfactory. This study aimed to evaluate the effectiveness and explore the therapeutic mechanisms of the combination of platelet-rich plasma (PRP) and ozone (O3) for knee OA. METHODS Thirty male rabbits were randomly divided into five groups (Control group, OA group, PRP group, O3 group, and PRP + O3 group). Rabbit model of OA were induced by improved Hulth surgery. Gross articular observation, histopathological examination and cartilage scoring system were used to assess the articular cartilage destruction. The bone morphogenetic protein-2 (BMP-2) mRNA expression in joint fluid was determined by qRT-PCR. The expression of type II collagen, matrix metalloproteinase-1 (MMP-1) of cartilage was detected via Immunohistochemistry. Pain behavior was observed by percent ipsilateral weight-bearing (PIW) asymmetry. RESULTS The content of platelet in PRP was increased by 6.2-times that in whole blood. Among induced OA groups (the OA, PRP, O3 and PRP + O3 group), PRP + O3 significantly inhibited the surgically induced increase in gross articular alterations, histopathological damage of cartilage and Mankin score when compared to the OA, PRP and O3 groups (P<0.05). Observed pain behavior by weight-bearing asymmetry, in the PRP + O3 group was reversed at 3 and 6 weeks after the administration of PRP + O3 (PIW asymmetry: -10.66%±1.172%). In addition, surgery-induced BMP-2 mRNA expression was significantly downregulated after the treatment of PRP, O3 and PRP + O3 (P<0.01). PRP + O3 group significantly increased the expression of type II collagen but decreased MMP-1 of cartilage in comparison to OA, PRP and O3 groups (P<0.05) by immunohistochemical analysis. CONCLUSIONS PRP combined with O3 may prevent cartilage destruction and improve weight-bearing asymmetry by restoring homeostasis between anabolism and catabolism of extracellular matrix in progressive OA. Furthermore, a combination of PRP and O3 might achieve even better results than the two agents alone.