| Research Abstract |
The purpose of this investigation is to clarify which MMPs are involved in the periodontal tissue remodeling during tooth movement and how the expression and activation of MMPs are regulated. Especially, direct induction of gene expression of any MMPs will be focused on, not only verify the indirect pathway through cytokine signaling.
1. We employed an animal model system to elucidate the histological changes during the tooth movement and changes in the gene expression patterns of MMPs by using in situ hybridization method. We found that the expression of MMPs-2, -8 and -13 were transiently promoted in the PDL cells, while the MMP-9 is only expressed in the osteoclasts.
2. Human PDL cells were subjected to two different type of mechanical stress ; tension-force and compressive-force, and showed similar pattern of mRNA expression. MMP-1 and -2 were up-regulated. Membrane type MMP, MT1-MMP was also detectable, and its expression level was not changed by mechanical stress. MMP-9 was not detected in this experiment. Only TIMP-1 mRNA Level was stable after mechanical stress. On the other hand, mRNA expression levels of TIMP-1, -2 were up-regulated. The changes of mRNA expression level showed similar pattern with the changes of mRNA level by the treatment of prostaglandin E2. Inducible prostaglandin synthase, COX-2 mRNA expression was also up-regulated by mechanical stress.
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