Vitamin D Inhibits Activities of Metalloproteinase-9/-13 in Articular Cartilage In Vivo and In Vitro

Low levels of serum vitamin D have been shown to accelerate progression of osteoarthritis. However, the role of vitamin D in articular cartilage degradation and osteoarthritis development is still unclear. This study investigated the effects of vitamin D on articular cartilage degradation by testing matrix metalloproteinase (MMPs) activities in articular cartilage using the rat vitamin D deficiency model at the animal level and rat articular chondrocytes at the cell level. The in vivo study showed vitamin D deficiency increased the expressions of MMP-9 and MMP-13 in rat articular cartilage, and the increase was inhibited by 1 alpha,25(OH)(2)D-3 supplementation. The increased production of MMP-9 and MMP-13 in the articular chondrocytes induced by tumor necrosis factor-alpha (TNF-alpha) or phorbol-12-myristate-13-acetate (PMA) was significantly suppressed by concomitant treatment with 1 alpha,25(OH)(2)D-3 in vitro. The increased level of C-telopeptide of type II collagen (CTX-II) induced by TNF-alpha or PMA was also significantly suppressed by concomitant treatment with 1 alpha,25(OH)(2)D-3 in vitro. Thus, vitamin D intake may inhibit MMP activities and take part in the process of articular cartilage degeneration and osteoarthritis progression.