Increase of MT1-MMP, TIMP-2 and Ki-67 proteins in the odontogenic region of the rat incisor post-shortening procedure.

MT1-MMP and TIMP-2 are well known for their roles in remodelling of extracellular matrix components. However, reports are emerging on the involvement of these molecules in cell kinetics. In the rat incisor tooth, a shortening treatment increases the eruption and cell proliferation rates. However, the role of MT1-MMP and TIMP-2 proteins in these processes is still to be evaluated. Male Wistar rats were divided in two groups. In the normofunctional group (NF) the lower teeth of the rats remained in a normal eruption process. In the hypofunctional group (HP) rats their lower left incisor tooth was shortened every 2 days during 12 days. The eruption rate was estimated during the shortening period and MT1-MMP, TIMP-2 and Ki-67 protein expression from the odontogenic region was measured after the treatment. In HP groups an increase in eruption rate, and in MT1-MMP/TIMP-2 and Ki-67 expression were observed. We conclude that there is a relationship between the increase in eruption rate, and in levels of MT1-MMP, TIMP-2 and Ki-67 in the HP group. This suggests that MT1-MMP and TIMP-2 may have some role in cell proliferation during the eruption of the rat incisor tooth.