Efeito da deficiência de magnésio sobre o metabolismo do tecido ósseo
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Data
2012-03-23
Autores
Belluci, Marina Montosa [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O magnésio (Mg+2) é um mineral que possui um importante papel na homeostase mineral, podendo afetar diretamente a função das células ósseas e a formação da hidroxiapatita. Entretanto, até o presente momento existem poucos estudos avaliando os mecanismos relacionados à alteração do metabolismo ósseo frente à deficiência de Mg. O objetivo desse estudo foi avaliar, in vitro, o efeito da deficiência de magnésio sobre a osteoclastogênese e atividade de osteoclastos. Também foi objetivo avaliar, in vivo, o efeito da deficiência de magnésio na dieta sobre o metabolismo ósseo, doença periodontal e tecido ósseo ao redor de implantes com osseointegração estabelecida. Para o estudo in vitro, foram avaliadas células indiferenciadas da medula óssea de ossos longos e mandíbula de camundongos. As células foram cultivadas em plástico e sobre tecido ósseo, em meios de cultura com diferentes concentrações de Mg (0.8 Mm que é considerada a quantidade adequada de Mg; e meios com redução do Mg, 0.4 Mm; 0.08 Mm; e 0 Mm). Após 3 dias de cultura, foram avaliadas a viabilidade celular, a taxa de proliferação celular e a expressão gênica, por PCR, de genes relacionadas à osteoclastogênese (c-fms, RANK, DC STAMP, c-fos, TNF-α e IL-1β) e ao metabolismo do Mg (TRPM-7 e MRS2). Após 6 dias de cultura, foram avaliados os parâmetros: número de células osteoclásticas (coloração de TRACP), atividade (liberação de TRACP) e taxa de proliferação celular. Após 8 dias de cultura a atividade dos osteoclastos foi avaliada por análise de pit de reabsorção. Para o estudo in vivo, foram utilizados 30 ratos, divididos em 2 grupos: grupo controle (CTL), que recebeu dieta com conteúdo adequado de magnésio, e grupo Mg, que recebeu dieta...
Magnesium (Mg) deficiency is very common condition in the world population. This mineral has an important role on bone homeostasis. However, there has been little research regarding the mechanisms in which magnesium deficiency alters bone metabolism. Also, the understanding of the factors associated to bone metabolism is of interesting for the prognosis of oral therapies, such as on periodontal disease and on osseointegrated dental implants. The aim of this study was to evaluate, in vitro, whether Mg deficiency affects the formation and/or activity of osteoclasts. And also to evaluate, in vivo, the effect of Mg intake deficiency on bone metabolism, periodontal disease and the bone tissue around osseointegrated implants. For the in vitro study, bone marrow cells from long bone and jaw of mice were seeded on plastic and on bone in medium containing different concentrations of Mg (0.8 mM which is 100% of the normal value, 0.4, 0.08 and 0 mM). The effect of Mg deficiency was evaluated on cell viability after 3 days and proliferation rate after 3 and 6 days, as was mRNA expression of osteoclastogenesis-related genes (M-CSF, RANK, c-fos, DC STAMP, TNF-α and IL-1β) and Mg-related genes (TRPM7 and MRS2). After 6 days of incubation, the number of tartrate resistant acid phosphatase-positive multinucleated cells (TRACP+-MNCs) was determined, and the TRACP activity of the medium was measured. Osteoclastic activity was assessed at 8 days by resorption pit analysis. For the in vivo studies, 30 rats received an implant in the right tibial metaphysis. After 60 days for healing of the implants, the animals were divided into groups according to the diet received. Control group (CTL) received a standard diet with adequate... (Complete abstract click electronic access below)
Magnesium (Mg) deficiency is very common condition in the world population. This mineral has an important role on bone homeostasis. However, there has been little research regarding the mechanisms in which magnesium deficiency alters bone metabolism. Also, the understanding of the factors associated to bone metabolism is of interesting for the prognosis of oral therapies, such as on periodontal disease and on osseointegrated dental implants. The aim of this study was to evaluate, in vitro, whether Mg deficiency affects the formation and/or activity of osteoclasts. And also to evaluate, in vivo, the effect of Mg intake deficiency on bone metabolism, periodontal disease and the bone tissue around osseointegrated implants. For the in vitro study, bone marrow cells from long bone and jaw of mice were seeded on plastic and on bone in medium containing different concentrations of Mg (0.8 mM which is 100% of the normal value, 0.4, 0.08 and 0 mM). The effect of Mg deficiency was evaluated on cell viability after 3 days and proliferation rate after 3 and 6 days, as was mRNA expression of osteoclastogenesis-related genes (M-CSF, RANK, c-fos, DC STAMP, TNF-α and IL-1β) and Mg-related genes (TRPM7 and MRS2). After 6 days of incubation, the number of tartrate resistant acid phosphatase-positive multinucleated cells (TRACP+-MNCs) was determined, and the TRACP activity of the medium was measured. Osteoclastic activity was assessed at 8 days by resorption pit analysis. For the in vivo studies, 30 rats received an implant in the right tibial metaphysis. After 60 days for healing of the implants, the animals were divided into groups according to the diet received. Control group (CTL) received a standard diet with adequate... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Osseointegração, Implantes dentários, Deficiencia de magnesio, Periodontia
Como citar
BELLUCI, Marina Montosa. Efeito da deficiência de magnésio sobre o metabolismo do tecido ósseo. 2012. 100 f. Tese (Doutorado) - Universidade Estadual Paulista, Faculdade de Odontologia de Araraquara, 2012.