Effects of Sulforaphane on Human Chondrocytes Cultured In Vitro

Chondrocyte dedifferentiation is the one of the major factors that affect the clinic outcomes of autologous chondrocyte implantation (ACI) for cartilage repair due to fibrocartilage formation. Molecules in the extracellular matrix (ECM) like type II collagen and proteoglycans play a key role in the quality of newly-formed cartilage. Sulforaphane (SFN), as a plant-derived compound, was investigated for its effects on human chondrocyte cultured in vitro in the present study. We showed a concentration of 8 mu M SFN would change the expression pattern of the ECM molecules of chondrocyte, with the increased ratio of type II collagen/type I collagen, increased expression of SOX9, BMP2 and decreased expression of matrix metallopeptidase 13 (MMP13). The change of the gene expression level would benefit for the inhibition of chondrocyte dedifferentiation in vitro, thus helping hyaline cartilage regeneration after ACI surgery. However, microarray analysis revealed expressions of gene clusters relating to cell proliferation and growth significantly changed and cell number decreased after SFN treatment, suggesting its negative role in chondrocyte expansion. Therefore, optimizing SFN concentration and the culture time might be a promising way for chondrocyte culture for clinic use.