Histomorphometry Analysis of Local Applicantion of Parathyroid Hormone in Rat Calvaria

Objectives: The aim of this study was to evaluate, by histomorphometric analysis, bone repair in critical defects in calvaria of rats after local application of PTH in a single dose.
Methods: Fourty-two male rats were divided into three groups: control group (C), Sponge Group (E) and PTH Group. A 5 mm critical-size defect was created in the calvaria of all animals. In Group C, the defects were filled only with blood clot, in Group E defects were filled with hydrolyzed collagen sponge and covered with bovine cortical membrane, while the PTH group defects were filled with hydrolyzed collagen sponge soaked in PTH and covered with bovine cortical membrane. The groups were subdivided for euthanasia at 15 and 60 days postoperatively. Histomorphometric analysis was held and the data were submitted to statistical analysis (Student's t test and Mann-Whitney test, p < 0.005).
Results: As a result, a significantly higher bone formation was obtained in the PTH group compared to the group E and in the group C when compared to group E at 15 days postoperatively. As for soft tissue, there was a larger amount in group E when compared to PTH group and the group C at 15 days postoperatively.
Conclusions: It is concluded that the local use of PTH Group promotes bone repair at 15 days postoperatively.