Imunolocalização de CSF-1, OPG e RANKL no periodonto relacionado ao esmalte de incisivos de ratos em erupção normal e contida / Immunolocalization of CSF-1, OPG and RANKL in the enamel-related periodontium of rat incisors in normal and immobilized eruption

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

In the rat incisors the face of the socket related to the enamel is resorpted continually on the inner side and formed on the outer side. A study accomplished at our laboratory showed that in rat incisors immobilized by a period of 18 days, there is a replacement of bone resorption in the face of the socket related to the enamel by bone formation, where osteoclasts were substituted by osteoblasts. CSF-1 and RANKL stimulate the proliferation and osteoclast differentiation while OPG has a potent osteoclastogenesis inhibitory activity. The aim of this study was to analyze the distribution and intensity of CSF-1, RANKL and OPG in periodontal tissues related to the enamel (PRE) of rat lower incisors, in normal eruption and after the period of 18 days of containment, using immunohistochemical technique and associating the quantitative analysis of osteoclasts. Fifteen male Wistar rats had their left lower incisor immobilized by means of a steel wire attached to the first left lower molar for 18 days. Fifteen rats with the left lower incisor in normal eruption were used as control. The eruption rate was measured using landmarks in the labial face of the crown. The animals were killed on day 18th and the region of the alveolar crest of the incisor was split. The incisors of 12 rats (6 control and 6 immobilized) were fixed and processed for embedding in Paraplast and immunohistochemical assay was accomplished using primary antibodies anti-CSF-1, OPG and RANKL. The immunostaining of the dental follicle was quantified by measure of the optical density, using the image analysis software Leica QWin (Leica imaging systems, Cambridge, UK) and both groups were compared by test t. To verify osteoclast activity, the incisors of 18 rats (9 control and 9 immobilized) were fixed and processed for embedding in Historesin and to make the tartrate resistant acid phosphatase (TRAP) evident. Osteoclasts TRAP positive in the whole length of the alveolar bone surrounding the enamel were counted. The incisor immobilization with steel wire was efficient. The difference in the number of osteoclasts between both rat groups was significant (p<0.001). In the normal incisor, the number of osteoclasts was threefold greater than in the immobilized tooth. In the dental follicle, there wasn t significant difference in the immunostaining intensity for CSF-1 and OPG between the groups (p>0.05). The immobilized incisor group showed immunostained intensity smaller than the normal incisor group (p <0.01). The studied molecules were present in PRE, in the region of the alveolar crest of rat lower incisor, in normal and immobilized eruption. There was a decrease in the intensity of RANKL immunostaining and in the number of osteoclasts in the immobilized condition. Hence, we concluded that changes in tissues of PRE, in the immobilized incisor, modify the RANKL/OPG ratio altering the metabolism of cells that participate in the bone remodeling

ASSUNTO(S)

bone remodeling remodelação ossea incisivos (dentes) tooth immunohistochemistry dentes - erupção incisors (tooth) imunohistoquimica

ACESSO AO ARTIGO

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