Figure 5

A. Type X collagen mRNA expression levels in hypertrophic chondrocytes cultured in different sponges subjected to different overall strains. Quantifying ColX mRNA was performed using real-time quantitative RT-PCR. The mRNA levels were normalized to 18S RNA, which served as the internal control. Chondrocytes from the central region of sponges subjected to 7.5% overall strain (3.75% local strain) had a significant increase in type X collagen mRNA production compared to the central region of non-loaded (0% strain group) sponges (n = 3/group; #: p = 0.02). Chondrocytes from the end region of the sponges subjected to 5% or 7.5% overall strains had a significant increase in type X collagen mRNA production in comparison to the end region of non-loaded (0% strain group) sponge (n = 3/group; *: p < 0.01). B. Western blot analysis of type X collagen from hypertrophic chondrocytes cultured in different sponges subjected to different overall strains. β-actin was used as an internal control of a housekeeping protein. Note the increasing strains result in an increase of type X collagen protein level while the level of β-actin remains constant. C: the center region of sponge; and E: the end region of sponge. Data shown are representative of those from three independent experiments.