Structural and functional changes in the alveolar bone osteoclasts of estrogen-treated rats

Structural and functional changes in the alveolar bone osteoclasts of estrogen-treated rats

Author Faloni, Ana Paula de Souza Autor UNIFESP Google Scholar
Sasso-Cerri, Estela Autor UNIFESP Google Scholar
Godoy Rocha, Fernanda Regina Google Scholar
Katchburian, Eduardo Autor UNIFESP Google Scholar
Cerri, Paulo Sergio Autor UNIFESP Google Scholar
Institution UNESP Univ Estadual Paulista
Universidade Federal de São Paulo (UNIFESP)
Abstract This study investigated structural and functional features of apoptotic alveolar bone osteoclasts in estrogen-treated rats. for this purpose, 15 female rats 22 days old were divided into three groups: Estrogen (EG), Sham (SG) and Control (CG). the rats of EG received daily intramuscular injection of estrogen for 7 days. the SG received only the oil vehicle. Maxillary fragments containing alveolar bone were removed and processed for light and transmission electron microscopy. Area (OcA) and number of nuclei (OcN) and bone resorption surface per TRAP-positive osteoclasts (BS/OC) were obtained. Vimentin, caspase-3 and MMP-9 immunoreactions, TUNEL/TRAP and MMP-9/TUNEL combined reactions were performed. in EG, the OcA, OcN and BS/Oc were reduced. Moreover, osteoclasts showed cytoplasm immunolabelled by caspase-3 and a different pattern of vimentin expression in comparison with CG and SG. MMP-9 expression was not affected by estrogen and the TUNEL-positive osteoclasts were MMP-9-immunolabelled. in EG, ultrastructural images showed that apoptotic osteoclasts did not exhibit ruffled borders or clear zones and were shedding mononucleated portions. TRAP-positive structures containing irregular and dense chromatin were partially surrounded by fibroblast-like cells. in conclusion, the reduction in the BS/Oc may be due to reduction in OcA and OcN; these effects seem to be related to vimentin disarrangement rather than to an interference of estrogen with osteoclast MMP-9 expression. Osteoclast apoptosis involves caspase-3 activity and vimentin degradation; these cells release portions containing one apoptotic nucleus and, subsequently, undergo fragmentation, giving rise to apoptotic bodies.
Keywords apoptosis
Language English
Sponsor Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Fundação para o Desenvolvimento da UNESP (FUNDUNESP)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Grant number FAPESP: 04/09898-0
Date 2012-01-01
Published in Journal of Anatomy. Malden: Wiley-Blackwell, v. 220, n. 1, p. 77-85, 2012.
ISSN 0021-8782 (Sherpa/Romeo, impact factor)
Publisher Wiley-Blackwell
Extent 77-85
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000297947100008

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