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(Referência obtida automaticamente do Google Scholar, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Birefringence of the secretory-stage enamel organic extracellular matrix from rats submitted to successive injections of bisphosphonates

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Autor(es):
do Espírito Santo‚ A.R. ; Frozoni‚ M.R.S. ; Ramos-Perez‚ F.M.M. ; Novaes‚ P.D. ; Line‚ S.R.P.
Número total de Autores: 5
Tipo de documento: Artigo Científico
Fonte: Connective Tissue Research; v. 51, n. 3, p. 208-215, 2010.
Resumo

The aim of the present study was to assess birefringence of the secretory-stage enamel organic extracellular matrix (ECM) and mechanical properties of mature enamel from rats treated with bisphosphonates. Longitudinal sections were obtained from upper incisors of rats that had been submitted to injections of bisodic etidronate (8 mg/Kg/day), sodium alendronate (30 mu g/Kg/day), or sodium chloride as control (8 mg/Kg/day) for 42 days. Sections were immersed in 80% glycerin for 30 min and optical retardation of birefringence brightness in the secretory-stage enamel organic ECM was determined in nanometers. Etidronate-treated rats exhibited extensive morphological changes in the secretory-stage enamel organic ECM inclusive nonbirefringent conspicuous incremental lines, but presented optical retardation values similar to those showed by control rats (p > 0.05). Birefringence of secretory enamel organic ECM from etidronate rats presented an irregular aspect. Alendronate-treated rats did not show morphological alterations in the secretory-stage enamel organic ECM, however, they presented significant reduction in optical retardation of birefringence brightness when compared with control and etidronate rats (p < 0.01). Alendronate and etidronate groups exhibited reductions of approximate to 6-10% in mature enamel cross-sectional microhardness when compared with control group (p < 0.01). Scanning electron microscopy analysis showed extensive alterations in mature enamel only from etidronate group with absence of enamel rods. The present work shows that bisphosphonates can affect the birefringence of the secretory-stage enamel organic ECM. The results presented here suggest that alterations in the supramolecular organization of the secretory-stage enamel organic ECM are a plausible mechanism by which environmental factors may cause enamel defects. (AU)

Processo FAPESP: 04/13255-8 - Efeito de alterações genéticas e ambientais sobre a birrefringência da matriz orgânica do esmalte dentário
Beneficiário:Alexandre Ribeiro do Espírito Santo
Modalidade de apoio: Bolsas no Brasil - Doutorado
Processo FAPESP: 04/10994-4 - Defeitos na formação do órgão dental
Beneficiário:Sergio Roberto Peres Line
Modalidade de apoio: Auxílio à Pesquisa - Temático