Desenvolvimento de um modelo experimental para o estudo da osteoporose / Development of an experimental model to study osteoporosis

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Osteoporosis is a disease characterized by low bone mass and deterioration of the microarchitecture of the skeleton, leading to an accentuated bone fragility and a consequent increase in the risk of fractures. Nowadays osteoporosis is being considered one of the largest and more preoccupying health problems in the world, which strikes men and women. An animal model with mice (Rattus norvegicus) is being used because it allows the access to information on the quality and bone structure that otherwise would not be obtained in patients of clinical selection, being therefore fundamental agents to accomplish an effective and safe measurement of the bone quality. The proposal of this model is to cause osteoporosis through castration, glucocorticoid administration, or the association of both, in males and females, and to evaluate that moment the disease starts. For the accomplishment of the experiment 192 adult mice were used (96 males and 96 females). They were divided in eight groups with 24 animals in each: group I - male control; group II - castrated males; group III - males with glucocorticoid therapy; group IV - castrated males with glucocorticoid therapy; group V - female control; group VI - castrated females; group VII - females with glucocorticoid therapy; group VIII - castrated females with glicocorticóide therapy. The collections took place to the 14, 28, 42 and 56 days after beginning of the administrating glucocorticoid in all the groups. It was performed plasmatic analysis of calcium, phosphorus and total proteins; quantitative analysis of calcium, phosphorus and magnesium of the humerus; flexing biomechanic test in shinbone and compression biomechanic test in lumbar vertebra (L5). Comparing the obtained results, all the experimental groups presented normal plasmatic concentrations of calcium:phosphorus (1:1 to 2:1) and bone concentrations of calcium:phosphorus (2:1) inferior to the normal rate, except for the control groups. In regarding to the biomechanic tests with males, the group IV showed smaller resistance to bone fracture, following by the group III and the group II when compared to the control group. In the groups of females it was verified that the group VI had a minimum bone loss, indicated mainly by the unbalance of the concentration of calcium:phosphorus in the bone and by the reduction of the rigidity observed in the biomechanic tests. On the other hand, the groups VII and VIII, presented inadequate bone concentration of calcium:phosphorus and bone fragility, which was observed in the flexing and compression tests, considering that the group VII presented minor rigidity average and the group VIII smaller resistance to fracture vertebra L5 and in shinbone compared to the control group.

ASSUNTO(S)

osteoporose osteoporosis glucocorticoid glicocorticóides patologia animal

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