Expression of MMP-2 and TIMP-1 during rapid maxillary expansion in rats

- Midpalatal expansion induced bone formation along the edges of the palatal bone.
- Expression of MMP-2 and TIMP-1 were significantly increased by expansion.
- The ratio of MMP-2/TIMP-1 was significantly enhanced during expansion.
- MMP-2 and TIMP-1 regulates midpalatal suture remodeling during maxillary expansion.

ObjectiveThe aim of this study was to investigate the expression of MMP-2 and TIMP-1 during midpalatal suture expansion in rats.Design72 male Wistar rats were randomly divided into 2 groups: the experimental group and the control group. In the experimental group, opening loops were applied across the midpalatal suture with an initial force of 50 g, whereas in the control group, rats were subjected to sham installation of opening loops without activation. On day 1, 4, 7 and 14, nine rats from each group were sacrificed, and the maxillae were dissected and prepared for Immunohistochemistry (IHC) and RT- PCR examination of MMP-2 and TIMP-1 expression.ResultsThe results of IHC and Real Time PCR revealed that both protein and mRNA expression of MMP-2 and TIMP-1 were significantly increased after midpalatal expansion, and the ratio of MMP-2/TIMP-1 was also significantly enhanced.ConclusionsThe data suggested that MMP-2 and TIMP-1 might play an important role during the mid-palatal suture remodeling process of maxillary expansion.