Apoptosis and Local Expression of Matrix Metalloproteinases and Their Tissue Inhibitors in Human Cleft Lip and Palate Disordered Tissue

Development of secondary palate involves epithelial- mesenchymal interactions and extensive remodeling of the extracellular matrix of the palatal shelves. Investigations demonstrate that key regulators in mentioned processes are matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). However, the data on distribution and localization of various MMPs and TIMPs, as well as apoptosis in human cleft-affected tissues are still not clear. Therefore in this study we focuse on the relative abundance and localization of MMPs and TIMPs in cleft lip and palate - affected tissue.
Materials and methods: The research involved 17 patients with cleft lip and palate at the age from seven years to 49 years. Tissue samples were collected during the surgical nasal correction procedure from the cleft-affected nasal region. Material was proceed for detection of MMP-2, MMP-8, MMP-9, TIMP-2 and TIMP-4 with biotinstreptavidin immunohistochemistry. TUNEL method was applied for detection of apoptosis. Distribution of immunoreactive structures was detected semi quantitatively.
Results: Our results demonstrated that increased expression of MMP-2, variable expression of MMP-9 and slight expression of MMP-8 is characteristic for cleft lip and palate affected cartilage, while clefts disordered bone in general shows slight expression of MMPs and more pronounced apoptosis. Expression of TIMPs, especially - TIMP-4, was more characteristic for cleft lip and palate affected nasal cartilage.
Conclusions: Considered as a whole, our results suggested that the cleft lip and palate affected cartilage seems is more elastic in tissue remodelling, what can probably result in qualitative postoperative healing.