Although the role of the abovementioned MMPs has already been examined in several experimental arthritis models, surprisingly there are only two studies focusing on MMPs (MMP-8 and -13) in the K/BxN serum-transfer murine arthritis, which is one of the most translational RA model (Garcia et al., 2010; Singh et al., 2013). This evidence concerns the gene MMP8 and rheumatoid arthritis.