Estudo do efeito anabolico do paratormonio humano (1-34) em cultura de osteoblastos induzidos a apoptose / Study of anabolic effect of human parathyroid hormone (1-340 in culture of osteoblasts induced to apoptosis

AUTOR(ES)

Sonia Andrade Silveira Vaz

DATA DE PUBLICAÇÃO

2006

RESUMO

It is still not clear why sustained elevation of parathyroid hormone (PTH) stimulates bone resorption, whereas intermittent administration stimulates bone formation. Intermittent PTH administration was recently approved by the United States Food and Drug Administration as the first form of osteoporosis therapy that increases bone mass de novo, reverses the bone deficit, providing a proof-of-principle that osteoblast-targeted (anabolic) agents can effectively reduce osteoporotic fractures. Considering indications that attenuation of osteoblast apoptosis by daily injections of PTH in mice should account for the increased number of osteoblasts and, thereby, the increased bone formation produced by this treatment regimen, in the present study we aimed to investigate the anti-apoptotic ability of hPTH (1-34) in cultured osteoblastic cells through induction by TNF-? in association with PTH anabolic treatment using a calvariaderived osteoblastic cell line. Cells were cultured in MEM-?, supplemented with FBS, ascorbic acid, ?-glycerphosphate and gentamicin, and were divided in experimental groups that received different treatments. In group I, cells were induced to apoptosis, receiveing treatment with TNF-?; in group II, cells were not induced to apoptosis and received intermittent treatment with hPTH(1-34); in group III, cells were induced to apoptosis and received intermittent treatment with hPTH(1-34); and in group IV, cells were not induced to apoptosis and didn?t receive intermittent treatment with hPTH(1-34) (control). For determination of cell death, two methods were used: staining with Trypan Blue and flow cytometry. The results were statistically analyzed and demonstrated that intermittent treatment with hPTH(1-34) was able to inhibit apoptosis induction by 60%, thereby increasing osteoblast number even in the presence of TNF-?

ASSUNTO(S)

morte celular flow cytometry citometria de fluxo cell death

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