To approach this problem, we focused on the gene ADAMTS5. In addition to being the aggrecanase principally responsible for the heightened degradation of the extracellular matrix molecule aggrecan seen in osteoarthritis [11], [12], its transcript is also strongly up-regulated in C2C12 cells after six days of differentiation (4.84-, 6.7-, 8.1-fold, 3 probes) [13]. This evidence concerns the gene ACAN and osteoarthritis.