Intermittent Administration Of Parathyroid Hormone Improves The Repairing Process Of Rat Calvaria Defects: A Histomorphometric And Radiodensitometric Study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Background: The aim of this study was to evaluate the effects of intermittent treatment of parathyroid hormone (PTH (1-34)) on the bone regeneration of critically-sized rat calvarial bone defects. Material and Methods: Thirty-two male rats were trephined (4mm fullthickness diameter), in the central part of the parietal bones and divided into 2 groups of 16. The PTH group received subcutaneous injections of PTH (1-34) at 40 mu g/kg, 3 times a week and the control (CTL) group received the vehicle in the same regimen. The rats were sacrificed at 4 weeks post-treatment regimen, the parietal bones were extracted and samples were evaluated through histomorphometry and radiodensitometry. Results: The histological observations showed that the PTH group presented more "island-like" new bone between the defect margins with fibrous tissues than did the CTL group. The PTH group significantly exhibited greater histologic bone formation than did the CTL group (1.5mm +/- 0.7; 1.9 mm +/- 0.6, p<0.05/ for residual bone defect). The radiodensitometry analysis revealed significant differences among the PTH and CTL groups (2.1 Al eq. +/- 0.04; 1.8Al eq. +/- 0.06, p