Apoptosis in the early involuting stellate reticulum of rat molar tooth germs

Apoptosis in the early involuting stellate reticulum of rat molar tooth germs

Autor Baratella, L. Google Scholar
Arana-Chavez, V. E. Google Scholar
Katchburian, E. Google Scholar
Instituição Universidade Federal de São Paulo (UNIFESP)
Universidade de São Paulo (USP)
Univ Ponta Grossa
Resumo When the enamel organ of the rat tooth germ is fully developed at the tip of the prospective cusp, amelogenesis begins, and at this site the overlaying stellate reticulum begins its involution. During the involution process, there is a gradual decrease in intercellular spaces, invasion by blood vessels, appearance of macrophage-like cells and reduction in the number of stellate reticulum cells. Since reduction or disappearance of cells during embryonic development in organs and tissues has been shown to occur by apoptosis, we decided to examine early involuting regions of the stellate reticulum in the hope of detecting apoptosis. for this purpose, upper first molars of Wistar newborn rats aged 1 and 3 days were fixed in formaldehyde for the TUNEL method and in glutaraldehyde-formaldehyde for light and electron microscopy. Paraffin sections revealed TUNEL-positive structures, i.e. brown-yellow-stained bodies, in the central portion of the stellate reticulum, and next to the outer enamel epithelium and stratum intermedium. Examination of ultrathin sections confirmed the TUNEL findings: some stellate reticulum cells showed nuclei containing crescent-like electron-opaque condensed masses of peripheral chromatin, typical of apoptosis. Also, apoptotic bodies of various sizes and appearances were frequently observed within stellate reticulum cells. We should like to suggest that apoptosis is associated with the reduction in the number of cells during regression of the reticulum.
Palavra-chave amelogenesis
programmed cell death
transmission electron microscopy
enamel organ
rodent molar teeth
Idioma Inglês
Data de publicação 1999-07-01
Publicado em Anatomy and Embryology. New York: Springer Verlag, v. 200, n. 1, p. 49-54, 1999.
ISSN 0340-2061 (Sherpa/Romeo, fator de impacto)
Publicador Springer
Extensão 49-54
Fonte http://dx.doi.org/10.1007/s004290050258
Direito de acesso Acesso restrito
Tipo Artigo
Web of Science WOS:000080685700005
Endereço permanente http://repositorio.unifesp.br/handle/11600/26102

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