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EFFETS DES GLUCOCORTICOIDES SUR LA MISE EN PLACE DES CENTRES D'OSSIFICATION CHEZ L'EMBRYON DE RAT.
Implication de certains gènes du développement

Abstract : In the fetal rat in late gestation, the rate of glucocorticoid (GC) fetal shows a peak of secretion between the 16th and 20th days of embryonic life, a phenomenon concomitant with the appearance of ossification centers in the 17th 19th day of gestation for the calvaria and the nasal septum, respectively. In cartilage, GC modulate the effect of insulin-mimetic factors (IGF-I and-II) by complex mechanisms and poorly defined, which we are interested. Our results show that GC, in physiological concentrations, can induce biomineralization of the extracellular matrix of nasal septum chondrocytes and osteoblasts from calvaria of fetal rats in primary culture (increased alkaline phosphatase, the mineral deposit, and GAG Co I). In the nasal septum, this induction is associated with differential regulation of IGFBP and their degradation fragments. The molecular mechanisms governing the differentiation of craniofacial structures by GC, in particular, regulation of homeotic family Msx and Dlx by this hormone are poorly understood. Part of our work has been to decipher the effect of GC on the expression of genes Msx-2, Dlx-5 and RUNX-2 during the mineralization of calvaria of rat fetuses. Our results indicate that GC induce in vitro and in vivo in the calvaria of fetal rats, the expression of homeobox genes Msx-2 gene Dlx5 and master RUNX-2, required for the induction of a functional marker of biomineralization, osteocalcin. In our laboratory, the involvement of gene Msx-1 during amelogenesis and dentinogenesis and the presence of a natural antisense RNA of this gene have been shown in mice. We have identified a homolog of this RNA AS rats. Our results show that the latter is expressed in the biomineralization of calvaria of fetal rats, and will share further study the role of this AS RNA in models in vitro and in vivo, and other First, to address the mechanisms of action of this RNA AS.
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https://tel.archives-ouvertes.fr/tel-00414235
Contributor : Reem Nadra <>
Submitted on : Tuesday, September 8, 2009 - 2:13:01 PM
Last modification on : Tuesday, August 11, 2020 - 12:12:01 PM
Long-term archiving on: : Tuesday, June 15, 2010 - 11:20:37 PM

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  • HAL Id : tel-00414235, version 1

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Rim Nadra. EFFETS DES GLUCOCORTICOIDES SUR LA MISE EN PLACE DES CENTRES D'OSSIFICATION CHEZ L'EMBRYON DE RAT.
Implication de certains gènes du développement. Sciences du Vivant [q-bio]. université Paris VII, 2004. Français. ⟨tel-00414235⟩

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