Nuclear pores in luteal cells during pregnancy and after parturition and pup removal in the rat: a freeze-fracture study
Biocell
; Biocell;34(2): 81-89, Aug. 2010. ilus, graf
Article
em En
| LILACS
| ID: lil-595042
Biblioteca responsável:
AR40.1
ABSTRACT
In a previous paper we described a pronounced increase of apoptotic nuclei in rat corpus luteum of pregnancy whose programmed chromatin degeneration was induced by the progesterone antagonist mifepristone. Those observations encouraged us to study the apoptotic nuclear membrane during pregnancy and after parturition and pup removal, by using a freeze-fracture technique which allows us to observe 'en face' the nuclear envelop and also permits nuclear pore counting. This study was complemented with the TUNEL assay (TdT-mediated dUTP nick-end labelling). Changes in nuclear pores during pregnancy begin with an intense reduction in number but still showing an even distribution on the nuclear membrane, never forming aggregations sharply separated from pore-free areas, which are characteristic of other apoptotic models. Electron microscopy of thin-sections shows, coincidently with findings in the freeze-fracture replicas, a moderately irregular aggregation of marginal heterochromatin condensations. After nuclear fragmentation and micronuclear formation, pores behave in the usual manner in other apoptotic models, i.e., mainly showing migrations of nuclear pores toward the chromatin-free areas. The present results support the hypothesis that nuclear pore complexes are dynamic structures, which permit their migration toward nuclear membrane areas devoid of chromatin aggregations that might block the nucleocytoplasmic transport in such areas.
Texto completo:
1
Índice:
LILACS
Assunto principal:
Corpo Lúteo
/
Poro Nuclear
/
Técnica de Fratura por Congelamento
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Pregnancy
Idioma:
En
Revista:
Biocell
Assunto da revista:
Clulas
Ano de publicação:
2010
Tipo de documento:
Article