Made available in DSpace on 2014-12-17T15:32:22Z (GMT). No. of bitstreams: 1 CassianoFWN.pdf: 2062817 bytes, checksum: d3cc1231e84c63282116f5950923db98 (MD5) Previous issue date: 2006-02-23 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The odontogenic myxoma shares cellular and structural aspects with dental papilla, which has been implicated as probable origin of this neoplasm. The aim of the present study was to perform a comparative immunohistochemical analysis for the expression of collagenase-1 (MMP-1) and gelatinases A (MMP-2) and B (MMP-9) in odontogenic myxomas and dental papilla of teeth germs. Twelve cases of odontogenic myxomas and eight specimens of teeth germs were selected. It was taken into consideration the presence or absence of immunoreactivity, the pattern of immunohistochemical distribution of proteases within extracellular matrix, as well as, the number of cells revealing immunostaining for matrix metalloproteinases (MMPs). It was verified a significant difference (p<0,05) in relation to MMP-2 immunoexpression, which was observed only within extracellular matrix of myxomas. Nevertheless, MMP-1 labeling was revealed by most of the cases of odontogenic myxoma, at levels close to those observed in dental papilla. In relation to the pattern of distribution, a significant difference was obtained between specimens (p<0,05), with neoplasms predominantly exhibiting a focal pattern for MMP-1. The quantitative analysis of neoplastic cells labeled for MMPs denoted a significant difference (p<0,05), demonstrating a higher proportion of MMP-1 in comparison to MMPs-2 and -9. It can be concluded that immunohistochemical expression of MMP-1 at levels comparable to those observed in dental papilla and quantitatively superior in relation to MMPs-2 and -9, suggest an implication of this protease on extracellular matrix degradation of odontogenic myxomas. Moreover, the possibility of interactions with receptors involved in cellular adhesion, particularly with integrins, suggests a plausible function on local invasiveness of such neoplasms. Additionally, the presence of a descent immunoexpression gradient for these MMPs on odontogenic myxomas, associated to substrate specificity inherent in each enzyme, suggest the existence of a coordinated mechanism between interstitial collagenase and gelatinases A and B in order to allow an efficient degradation of extracellular matrix and local invasion by neoplastic cells / O mixoma odontog?nico compartilha aspectos celulares e estruturais com a papila dent?ria, tendo-se implicado esta ?ltima como prov?vel origem deste neoplasma. O prop?sito desta pesquisa consistiu em analisar comparativamente a express?o imuno-histoqu?mica de colagenase-1 (MMP-1) e gelatinases A (MMP-2) e B (MMP-9) em mixomas odontog?nicos e papilas de germes dent?rios. Foram selecionados 12 casos de mixoma odontog?nico e 08 esp?cimes de germes dent?rios, para an?lise da presen?a ou aus?ncia de express?o imunohistoqu?mica e padr?o de distribui??o destas proteases em meio ? matriz extracelular, bem como, o n?mero de c?lulas positivamente marcadas para estas metaloproteinases de matriz (MMPs). Constatou-se diferen?a significativa (p<0,05) em rela??o ? imunorreatividade para MMP-2, apresentando-se expressa apenas em meio ? matriz extracelular dos mixomas. Para MMP-1 foi verificada imunorreatividade na maioria dos casos de mixomas, com propor??es semelhantes ?s constatadas nas papilas dent?rias. Em rela??o ao padr?o de distribui??o, evidenciou-se diferen?a significativa apenas para MMP-1 (p<0,05), com predomin?ncia do padr?o focal nos neoplasmas. Por sua vez, a quantidade de c?lulas imunorreativas ?s proteases, nos mixomas odontog?nicos, revelou diferen?as significativas (p<0,05), estando a MMP-1 presente em maiores propor??es, em compara??o com as MMPs-2 e -9. Concluiu-se que a express?o de MMP-1, em n?vel compar?vel ao constatado nas papilas de germes dent?rios e numericamente superior ?s MMPs-2 e -9, sugere a implica??o desta protease no processo de degrada??o da matriz extracelular nos mixomas odontog?nicos e, em decorr?ncia da possibilidade de associa??o das MMPs a receptores envolvidos no processo de ades?o celular, especialmente ?s integrinas, ainda um prov?vel papel na invasividade local destes neoplasmas. Adicionalmente, a evidencia??o de um gradiente descendente na express?o imuno-histoqu?mica das MMPs nos mixomas odontog?nicos, associada ? especificidade de substrato inerente a cada uma destas proteases, sugerem a exist?ncia de um mecanismo coordenado entre colagenase intersticial e gelatinases A e B, direcionado ? degrada??o eficiente da matriz extracelular e invas?o local por parte das c?lulas neopl?sicas