Catabolic inflammatory cytokines are prevalent in osteoarthritis (OA). The purpose of this study was to evaluate an autologous protein solution (APS) as a potential chondroprotective agent for OA therapy. APS was prepared from platelet-rich plasma (PRP). The APS solution contained both anabolic (bFGF, TGF-b1, TGF-b2, EGF, IGF-1, PDGF-AB, PDGF-BB, and VEGF) and antiinflammatory (IL-1ra, sTNF-RI, sTNF-RII, IL-4, IL-10, IL-13, and IFNg) cytokines but low concentrations of catabolic cytokines (IL-1a, IL-1b, TNFa, IL-6, IL-8, IL-17, and IL-18). Human articular chondrocytes were pre-incubated with the antagonists IL-1ra, sTNF-RI, or APS prior to the addition of recombinant human IL-1b or TNFa. Following exposure to inflammatory cytokines, the levels of MMP-13 in the culture medium were evaluated by ELISA. MMP-13 production stimulated in chondrocytes by IL-1b or TNFa was reduced by rhIL-1ra and sTNF-RI to near basal levels. APS was also capable of inhibiting the production of MMP-13 induced by both IL-1b and TNFa. The combination of anabolic and anti-inflammatory cytokines in the APS created from PRP may render this formulation to be a potential candidate for the treatment of inflammation in patients at early stages of OA. ß