Estudo dos mecanismos envolvidos no processo de diferenciação em linhagem osteogênica de células-tronco mesenquimais da medula óssea de ratos Wistar e ratos espontaneamente hipertensos (SHR)
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2014-03-07
Autores
Barros, Thamine Landim de [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Células-tronco mesenquimais (CTMs) obtidas a partir da medula óssea são capazes de se diferenciarem, sobretudo, em condrócitos, adipócitos e osteoblastos. Durante a osteogênese in vitro, alguns parâmetros são utilizados para caracterizar este processo, tais como atividade da fosfatase alcalina (FAL), mineralização e expressão de proteínas associadas à osteoblastos. Ratos espontaneamente hipertensos (SHR) são um modelo animal de hipertensão essencial humana e desenvolvem hipertensão após 4 semanas de idade. Esta linhagem apresenta alterações significativas no metabolismo ósseo. O objetivo do presente estudo foi investigar se, o genótipo hipertensivo poderia interferir na diferenciação osteoblástica das CTMs de ratos SHR e qual mecanismo está alterado quando comparadas com a linhagem progenitora, ratos Wistar. Para isso, nós obtivemos CTMs da medula óssea de ratos Wistar e SHR com 4 semanas de idade, sem a hipertensão estabelecida, afim de avaliar somente o possível efeito do genótipo hipertensivo na diferenciação osteogênica in vitro. Nós induzimos, ou não, a diferenciação osteogênica in vitro por meio da utilização dos indutores osteogênicos: ácido ascórbico, ?-glicerofosfato e dexametasona. Os resultados demonstraram que, CTMs indiferenciadas de SHR (SHRC) demonstraram taxa de proliferação aumentada em comparação a CTMs, na mesma condição, de Wistar (WC), e após a indução da osteogênica, a taxa de proliferação apresentou uma diminuição acentuada no grupo SHR (SHRMO) do que no grupo Wistar na mesma condição (WMO). Embora não fora observada diferença significativa na atividade da FAL entre SHRMO e WOM no 7° dia, a mineralização e a diferenciação osteoblástica foram menores no grupo SHRMO no mesmo período experimental. Os fatores de transcrição Osterix e ?-catenina parecem estar envolvidos na diferenciação reduzida no grupo SHRMO...
Mesenchymal stem cells (MSCs) from bone marrow are able to differentiate mainly into chondrocytes, adipocytes and osteoblasts. During in vitro osteogenesis, some parameters are used to characterize this process, such as the activity of alkaline phosphatase (ALP), mineralization and osteoblast-associated proteins expression. Spontaneously hypertensive rats (SHR) is an animal model of human essential hypertension. This animals developing hypertension after 4 weeks of age. This strain shows significant changes in bone metabolism. The aim of this study was to investigate whether the hypertensive genotype could influence the osteoblastic differentiation of MSCs from SHR and which mechanism are altered when compared to the parental strain, Wistar rats. For that, we have obtained bone marrow MSCs from Wistar and SHR rats at 4 weeks of age, without hypertension established in order to evaluate only the possible effect of hypertensive genotype on osteogenic differentiation in vitro. We induced or non-osteogenic differentiation in vitro using osteogenic inducers: ascorbic acid, dexamethasone and ?-glycerophosphate. The results demonstrate that undifferentiated MSCs SHR (SHRC) showed increased proliferation rate compared to MSCs, in the same condition Wistar (WC) and after osteogenic induction, proliferation rate showed a marked decrease in SHR (SHRMO) than in Wistar group in the same condition (WMO). Although it was not observed significant difference in ALP activity between WMO and SHRMO on day 7, mineralization and osteoblast differentiation were lower on group SHRMO in the same experimental period. The transcription factors Osterix and ?-catenin appear to be involved in reduced differentiation in SHRMO group because they showed lower expression in this experimental group. Furthermore, the decreased...
Mesenchymal stem cells (MSCs) from bone marrow are able to differentiate mainly into chondrocytes, adipocytes and osteoblasts. During in vitro osteogenesis, some parameters are used to characterize this process, such as the activity of alkaline phosphatase (ALP), mineralization and osteoblast-associated proteins expression. Spontaneously hypertensive rats (SHR) is an animal model of human essential hypertension. This animals developing hypertension after 4 weeks of age. This strain shows significant changes in bone metabolism. The aim of this study was to investigate whether the hypertensive genotype could influence the osteoblastic differentiation of MSCs from SHR and which mechanism are altered when compared to the parental strain, Wistar rats. For that, we have obtained bone marrow MSCs from Wistar and SHR rats at 4 weeks of age, without hypertension established in order to evaluate only the possible effect of hypertensive genotype on osteogenic differentiation in vitro. We induced or non-osteogenic differentiation in vitro using osteogenic inducers: ascorbic acid, dexamethasone and ?-glycerophosphate. The results demonstrate that undifferentiated MSCs SHR (SHRC) showed increased proliferation rate compared to MSCs, in the same condition Wistar (WC) and after osteogenic induction, proliferation rate showed a marked decrease in SHR (SHRMO) than in Wistar group in the same condition (WMO). Although it was not observed significant difference in ALP activity between WMO and SHRMO on day 7, mineralization and osteoblast differentiation were lower on group SHRMO in the same experimental period. The transcription factors Osterix and ?-catenin appear to be involved in reduced differentiation in SHRMO group because they showed lower expression in this experimental group. Furthermore, the decreased...
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Palavras-chave
Células mesenquimais estromais, Osteoblastos, Ratos endogâmicos SHR, Mesenchymal Stromal Cells
Como citar
BARROS, Thamine Landim de. Estudo dos mecanismos envolvidos no processo de diferenciação em linhagem osteogênica de células-tronco mesenquimais da medula óssea de ratos Wistar e ratos espontaneamente hipertensos (SHR). 2014. 75 f. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Odontologia de Araçatuba, 2014.