The inhibitory effect of Sr and/or Si ions on hedgehog pathway and metabolic activity in OA chondrocytes. (A) IHH gene, (B) Patched-1 gene, (C) Gli-1 gene, (D) Adamts-5 gene, (E) MMP3 gene, (F) MMP13 gene. In OA model, Sr or Si ions protected chondrocytes by inhibiting the hedgehog pathway and metabolic activity within the concentration range of Sr 0.25-4 mg/L or Si 0.5-8 mg/L. Furthermore, Sr and Si ions together inhibited the hedgehog pathway, as well as down-regulated MMP13 gene expression within the concentration range of Sr 0.25-4 mg/L and Si 0.5-8 mg/L to protect chondrocytes from OA. In addition, the inhibitory effect on hedgehog pathway was superior to that of SNAT-1 at the concentration of Sr 1 mg/L and Si 4 mg/L. IL-1β plays a key role in OA pathogenesis, SANT-1 is a hedgehog signaling inhibitor. The relative gene amount of CTR groups was set as 1, the value of expression gene was the fold change relative to CTR. Repeat number: n=3. (*p<0.05, **p<0.01, ***p<0.001).