Evaluation of the expression levels of Mmp3 in the subchondral bone of the E-Group and the S-Group using immunohistochemistry staining.

<p>The antibody against Mmp3 was used to assess the spatial and temporal expression of the protein by colorimetric detection (brown precipitate). The mononuclear cells of both groups appeared positive for the same levels of Mmp3 at 1, 2 and 4 weeks post-surgery. The polynuclear giant cells in the subchondral bone of the E-Group expressed Mmp3 in their cytoplasm 1 and 2 weeks post-surgery, but not at 4 weeks, wheras those of the S-Group appeared negative at all three time points post-surgery. Specifically, obvious differences were discovered in the E-Group between 1 week and 2 weeks post-surgery, including stronger positive signals and more positive cells at 1 week compared with 2 weeks post-surgery. All sections were counterstained with hematoxylin (blue stain). The scale bars for 10X, 40X and Cell-view are 200 µm, 50 µm, and 50 µm respectively.