Avaliação da qualidade óssea no reparo de defeitos ósseos sob a ação do risedronato e da deficiência estrogênica
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Data
2009-07-24
Autores
Senra, Giselle Segnini [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O aumento da expectativa de vida amplia as possibilidades de doenças como a osteoporose, que elevam a ocorrência de fraturas e demandam longo tratamento. Nos últimos anos, muita atenção tem sido dada aos efeitos potenciais dos medicamentos para a osteoporose na reparação de fraturas advindas desta doença. O objetivo deste trabalho foi avaliar o efeito do Risedronato (10,5 mg/kg/semana) na qualidade óssea do reparo ósseo em ratas com deficiência estrogênica. Para isso, 84 ratas foram submetidas à ovariectomia e 42 ratas à cirurgia sham. Após 35 dias, lesões de 2,5 mm foram realizadas nos fêmures quando, então, se iniciou a medicação. Os animais ovariectomizados foram divididos em dois grupos, um recebendo risedronato e o outro recebendo água filtrada como placebo. Os animais foram sacrificados com 18, 45 e noventa dias de reparo. Cortes centrais dos defeitos de metade das ratas receberam análise morfológica ao MEV, teste de microdureza Vicker’s e através do μED-XRF foi realizado mapeamento, micro-análise semi-quantitativa do Ca e P do mineral ósseo e relação Ca/P. A outra metade dos animais, com o fêmur esquerdo operado (O) e o direito não-operado (NO), teve esses ossos congelados até a realização de ensaio de flexão em três pontos gerando valores de força máxima, rigidez e energia da força máxima. Para a análise estatística foram utilizados os testes: t-Student, Análise de Variância ANOVA, Comparação Múltipla de Tukey e Correlação Linear, todos com nível de significância de 5%. A microdureza (HV) se mostrou fortemente relacionada com as concentrações de Ca e de P, e moderadamente correlacionada com Ca/P. A ovariectomia não afetou os valores de microdureza e módulo de elasticidade (E), mas diminuiu a concentração de Ca, de P e a relação Ca/P aos 18 dias. O tratamento com risedronato aumentou os valores de HV e E, mas não interferiu...
The increase in life expectancy is associated with a higher osteoporosis incidence, which elevates the occurrence of bone fractures, and demand long treatment. In the last years, it’s increasing de interest in the potential effects of osteoporosis medication on bone fractures healing. The aim of this work will be to evaluate the effects of Risedronate (10,5 mg/Kg/week) on bone quality in the femoral callus in rats with induced osteopenia. For that, 84 rats were subject to ovariectomy, and 42 were sham operated. After 35 days, 2,5 mm monocortical bone lesions were drilled on all animals femurs. Then, treatment began. The ovariectomized animals, divided in two groups, received Risedronate or drinking water as a placebo. The animals were sacrificed at 18, 45 and ninety days of bone repair. The central sections from bone defects from half of the rats were analyzed to determine their morphology using an SEM, electron probe microanalysis (μED-XRF) from bone mineral Ca, P and Ca/P ratio and Vicker’s microhardness. Another half of the animals had the left femur operated (O), and the right one, non operated (NO), both frozen till be tested in threepoint flexure to derive maximum load, stiffness and energy absorbed to maximum load. Statistical analyses were performed using t-Student, ANOVA, Tukey and Linear Correlation tests, considering 5% significance. Microhardness was strongly correlated to Ca and P concentrations but it was moderately correlated with Ca/P. Ovariectomy didn’t affect microhardness (HV) and Young modulus (E) but diminished, at 18 days, Ca/P, Ca and P concentrations. Risedronate treatment achieved increasing in HV and E without interference on Ca/P, Ca and P concentration of bone callus. Ovariectomy and healing time almost didn’t have influence on biomechanical properties of O, different from risedronate, which diminished these properties at 18 and 45 days. The HV and E from... (Complete abstract click electronic access below)
The increase in life expectancy is associated with a higher osteoporosis incidence, which elevates the occurrence of bone fractures, and demand long treatment. In the last years, it’s increasing de interest in the potential effects of osteoporosis medication on bone fractures healing. The aim of this work will be to evaluate the effects of Risedronate (10,5 mg/Kg/week) on bone quality in the femoral callus in rats with induced osteopenia. For that, 84 rats were subject to ovariectomy, and 42 were sham operated. After 35 days, 2,5 mm monocortical bone lesions were drilled on all animals femurs. Then, treatment began. The ovariectomized animals, divided in two groups, received Risedronate or drinking water as a placebo. The animals were sacrificed at 18, 45 and ninety days of bone repair. The central sections from bone defects from half of the rats were analyzed to determine their morphology using an SEM, electron probe microanalysis (μED-XRF) from bone mineral Ca, P and Ca/P ratio and Vicker’s microhardness. Another half of the animals had the left femur operated (O), and the right one, non operated (NO), both frozen till be tested in threepoint flexure to derive maximum load, stiffness and energy absorbed to maximum load. Statistical analyses were performed using t-Student, ANOVA, Tukey and Linear Correlation tests, considering 5% significance. Microhardness was strongly correlated to Ca and P concentrations but it was moderately correlated with Ca/P. Ovariectomy didn’t affect microhardness (HV) and Young modulus (E) but diminished, at 18 days, Ca/P, Ca and P concentrations. Risedronate treatment achieved increasing in HV and E without interference on Ca/P, Ca and P concentration of bone callus. Ovariectomy and healing time almost didn’t have influence on biomechanical properties of O, different from risedronate, which diminished these properties at 18 and 45 days. The HV and E from... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Osteoporose, Microscopia eletronica de varredura, Testes de dureza, Ossos - Regeneração, Osteoporosis, Rats, Spectrometry
Como citar
SENRA, Giselle Segnini. Avaliação da qualidade óssea no reparo de defeitos ósseos sob a ação do risedronato e da deficiência estrogênica. 2009. 176 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Odontologia de São José dos Campos, 2009.