RESUMO
The aim of this study was to compare the immunohistochemical expression of matrix metalloproteinases (MMPs) 1, 2, and 9 in odontogenic myxomas and dental germ papillae. Twelve cases of odontogenic myxoma and eight tooth germ specimens were selected for analysis of the immunohistochemical expression and the pattern of distribution of MMPs 1, 2, and 9 in extracellular matrix (ECM), as well as of the number of MMP-positive cells. MMP-2 was expressed only in the ECM of myxomas (p<0.05). No significant difference was observed between ECM immunoreactivity for MMP-9 in myxomas and dental papillae (p>0.05). MMP-1 immunoreactivity was detected in most myxoma cases at a proportion similar to that observed in dental papillae (p>0.05). A significant difference was observed in the number of immunoreactive cells in myxomas (p<0.05), MMP-1 being present at higher proportions than MMPs 2 and 9. There was a gradient in the expression of MMPs in the ECM and in neoplastic cells of odontogenic myxomas, with higher immunoreactivity to MMP-1 and lower immunoreactivity to MMP-9. Taken together, our results suggest the existence of a coordinated mechanism between MMPs 1, 2, and 9 that aimed at the efficient degradation of extracellular matrix in odontogenic myxomas.
Assuntos
Papila Dentária/enzimologia , Imuno-Histoquímica , Neoplasias Maxilomandibulares/enzimologia , Metaloproteinase 1 da Matriz/análise , Metaloproteinase 2 da Matriz/análise , Metaloproteinase 9 da Matriz/análise , Mixoma/enzimologia , Tumores Odontogênicos/enzimologia , Matriz Extracelular/enzimologia , Humanos , Neoplasias Maxilomandibulares/patologia , Mixoma/patologia , Tumores Odontogênicos/patologiaRESUMO
Tooth germ development is associated with morphological and biochemical changes of the dental papilla and enamel organ. Enzymes with gelatinolytic activities were studied by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and enzymography in tooth germ of newborn to 15-day-old rats. Three major bands with gelatinolytic activity were detected at all periods and characterized as the latent and active forms of MMP-2 using their molecular weight and activity dependent on Zn++ and Ca++ ions as criteria. Expression and activity of MMP-2 increased progressively from 0 to 15 days after birth. Mechanical separation of the tooth germ from 10-day-old rats showed that the gelatinolytic activity was localized mainly in the dental papilla and not the dental organ. These data indicate that the expression and activity of MMP-2 varies during the development and maturation of rat first molar tooth germ.