Figure 4. Up-regulation of Wnt signaling and down-regulation of Klotho in chondrocytes treated by CTS. Chondrocytes were were pretreated with cyclic tensile strain (0.1-1Hz) for 48 hours Expression of Klotho, Wnt1, Wnt4 and Wnt7a in the cell supernatant and GSK3β, p-GSK3β, MMP2, MMP9 and β-catenin (cytoplasm/nucleus) in the cell of mouse cartilage. (A) Western blot analyses show that CTS induced these proteins expression in a tension-dependent manner. (B) Cytocol/nuclear separation was undertaken to assess the enrichment of β-catenin in the nuclei in chondrocytes treated by CTS. The upregulation level of β-catenin localized in nucleus was more obvious than that remained in cytosol in CTS groups than control group. Representative Western blots (A and B) and quantitative data (C and D) are presented. *P<0.05 versus controls (n=3). (E) The RT-PCR results showed periodic CTS dependent inhibition of Klotho expression. (F, G) The results of RT-PCR showed that the expression of MMP-2, MMP-9 was stimulated by periodic CTS dependent stimulation. Results were obtained via the expression of three individual experiments performed in triplicate for each condition. *P < 0.05, **P < 0.01.