Analysis of early biochemical markers and regulation by tin protoporphyrin IX in a model of spontaneous osteoarthritis.

Age-related changes in joint tissues lead to osteoarthritis (OA). Detection of early changes in OA patients may help to initiate treatments before the establishment of irreversible joint destruction. STR/ort mice develop with age a severe degenerative joint disease that resembles human OA thus allowing the investigation of biochemical markers as well as new treatments in an accelerated time frame. We have analyzed the changes in serum levels of different mediators during the early phases of idiopathic OA in STR/ort mice. Serum levels of matrix metalloproteinase-3 (MMP-3) but not those of tumor necrosis factor-α, interleukin(IL)-1β, IL-17 or prostaglandin E(2) correlated with histopathological changes in knees of STR/ort mice at 9 weeks. Treatment of animals with tin protoporphyrin IX (SnPP, 12 mg/kg/dayi.p.) for 4 weeks significantly reduced the progression of OA. Our data suggest that MMP-3 is a sensitive biomarker to detect early OA alterations and that SnPP could be a protective agent in OA.