Parâmetros mecânicos, físicos e químicos na avaliação de mandíbulas de ratos deficientes em esteróides sexuais

Autor: Luciana Armada Dias
Jazyk: portugalština
Rok vydání: 2009
Předmět:
Zdroj: Biblioteca Digital de Teses e Dissertações da UERJUniversidade do Estado do Rio de JaneiroUERJ.
Druh dokumentu: Doctoral Thesis
Popis: O aumento da expectativa de vida vem elevando a ocorrência das alterações degenerativas comuns à terceira idade, como a osteoporose. Essa doença sistêmica também freqüente no hipogonadismo, afeta o metabolismo ósseo comprometendo inclusive a mandíbula. O objetivo deste estudo foi avaliar de que forma a deficiência de esteróides sexuais, induzida por orquiectomia ou ovariectomia, influencia o processo de remodelação óssea da mandíbula de ratos por períodos experimentais crônicos. Ratos Wistar, com 3 meses, foram divididos em três grupos experimentais: controles (C), castrados (ORQ; OVX) e castrados com tratamento hormonal (ORQ + PT - propionato de testosterona, 0,4 mg/100g PC/dia; OVX + BE - benzoato de estradiol, 0,7 g/100g PC/dia). As fêmeas foram previamente avaliadas por citologia vaginal e somente as que apresentaram o ciclo estral regular foram utilizadas. A massa corporal foi verificada semanalmente e ao final dos períodos experimentais (90, 120 e 150 dias) os animais foram sacrificados. O sangue foi coletado e o soro armazenado para posterior análise. As mandíbulas, fêmures e colunas foram excisados, medidos e preparados para análises da densidade mineral óssea e das propriedades físicas e biomecânicas. Observamos que com a castração, machos apresentaram baixo ganho de massa corporal (90d: 12%, 120d: 24% e 150d: 13% a menos que C, p< 0,05), ao contrário das fêmeas (90d: 38% e 120d: 41% a mais que C, p< 0,05). As medidas de todos os ossos foram menores tanto em machos como em fêmeas (♂ - 90d: vértebra 11.8%, fêmur 4.4%, côndilo MD 9.4%, côndilo VL 16.6%; 120d: vértebra 13.6%, fêmur 4%, côndilo mandibular MD 9%, côndilo mandibular VL 22.2%; 150d: vértebra 16.8%, fêmur 6%, côndilo mandibular MD 21.6%, côndilo mandibular VL 29.1% e ♀ - 90d: vértebra 7.7%, fêmur 5.6%, côndilo mandibular MD 29.1 %, côndilo mandibular VL 11.8%; 120d: vértebra 15.9 %, fêmur 6.1%, côndilo mandibular MD 33.6%, côndilo mandibular VL 14.8%; 150d: vértebra 21.6%, fêmur 5.42%, côndilo mandibular MD 29.1%, côndilo mandibular VL 15.1% a menos que C, p< 0,05), em todos os períodos experimentais. Em ambos os sexos as concentrações séricas de esteróides sexuais, fósforo e fosfatase alcalina foram menores em relação ao grupo controle, p
The increase in the life expectancy has been raising the occurrence of common degenerative alterations in aging population, as osteoporosis. This systemic disease is also frequent in hypogonadism and affects the bone metabolism, included mandibular bone. The aim of this study was to evaluate how sex steroid deficiency, induced by orchiectomy (ORX) or ovariectomy (OVX), influences on mandible bone remodeling of rats, in groups of chronic experimental periods. Wistar rats, 3 mouths, had been divided in three groups: controls (C), castrated (ORX; OVX) and castrated with hormonal treatment (ORX+TP testosterone propionate, 0,4 mg/100g BW/day; OVX+EB - estradiol benzoate, 0.7 g/100g BW/day). Females were previously evaluated by vaginal cytology and only rats with regular estrous cycle were used. The corporal mass was weekly verified and after experimental periods (90, 120 and 150 days), the animals were sacrificed. The blood was collected and serum stored for posterior analysis. Mandibles, femurs and columns were excised, measured and prepared to analyses of bone mineral density and physical and biomechanical properties. After castration, males presented low gain in body mass (90d: 12%, 120d: 24% and 150d: 13% lower than C, p< 0,05), in contrast of females (90d: 38% and 120d: 41% upper than C, p< 0,05). The measures of all bones were lower in males and in females (♂ - 90d: vertebrae 11.8%, femur 4.4%, mandibular condyle MD 9.4%, mandibular condyle VL 16.6%; 120d: vertebrae 13.6%, femur 4%, mandibular condyle MD 9%, mandibular condyle VL 22.2%; 150d: vertebrae 16.8%, femur 6%, mandibular condyle MD 21.6%, mandibular condyle VL 29.1% and ♀ - 90d: vertebrae 7.7%, femur 5.6%, mandibular condyle MD 29.1 %, mandibular condyle VL 11.8%; 120d: vertebrae 15.9 %, femur 6.1%, mandibular condyle MD 33.6%, mandibular condyle VL 14.8% and 150d: vertebrae 21.6%, femur 5.42%, mandibular condyle MD 29.1%, mandibular condyle VL 15.1% lower than C, p< 0,05), in all experimental periods. Males and females presented serum concentration of sex steroid hormones, phosphate and alkaline phosphatase lower than control group, p< 0,05 (Testosterone - 90d: 87%,120d: 87.5%,150d: 90.4%; Estradiol - 90d: 85.8%, 120d: 80.8%, 150d: 71.5%; Phosphate - ORX - 120d: 7.5%, 150d: 9.2% and OVX 90d: 17.2%, 120d: 16%, 150d: 24%; Alkaline phosphatase - ORX - 90d: 7%, 120d: 6.8%, 150d: 9.5% and OVX 90d: 21.2%, 120d: 26.1%, 150d: 43.3%). No significant differences were found in the males calcium concentration, but it was lower in castrated females (90d: 13.1%, 120d: 11.7%, 150d: 26.2%, p< 0,05).The bone mineral density and biomechanical properties of vertebrae and femur were reduced earlier in females than in males (♀ - vertebrae from 90d and femur from 120d; ♂ - vertebrae from 120d and femur from 150d, p< 0,05). However, mandibles were affected only in 150d males. There werent significant alterations on the physical properties. In conclusion, gonadal function loss caused low bone mass, preferentially in trabecular bone, affected females earliest than males and its decreases more with aging. Mandibular bone is affected in chronic periods principally when associated with masticatory activities alterations. Bones alterations resulted from Hypogonadism were minimized, by estradiol benzoate or testosterone propionate treatment, in female and male, respectively.
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