Effect of platelet rich fibrin associated or not with synthetic bone graft on bone healing of critical-size defects in calvaria of ovariectomized rats: a histomorphometry, microtomography and immunohistochemical study

Abstract

The purpose of this study is to evaluate the effects of Platelet Rich Fibrin (PRF) on healing of bovine bone grafts (XENO) placed in surgically created critical-size defects (CSD) in calvaria of ovariectomized rats. 32 rats will be divided into 4 groups: C, PRF, XENO and PRF-XENO. The animals will be submitted to bilateral ovariectomies at baseline. After 3 months, a 5 mm diameter CSD will be created in the calvarium of each animal. In Group C, the defect will be filled by blood clot only. In PRF Group, the defect will be filled by PRF. In Group XENO, it will be filled with particulate bovine bone graft. In Group PRF-XENO, the defect will be filled with particulate bovine bone graft combined with PRF. All animals will be euthanized at 4 months after the start of the study. The following parameters will be analyzed: i) bone area, bone mineral density and bone volume (micro-CT); ii) The amount of newly formed bone and the histopathological features of the bone tissue with histomorphometric analysis; iii) expression of Vascular endothelial growth factor, Proliferating cell nuclear antigen, Runt-related transcription factor-2, Osteocalcin, Osteopontin and Bone morphogenetic protein-2 with immunohistochemical reactions (streptavidin-biotin-peroxidase). The data obtained will be subjected to statistical analysis (p < 0.05). (AU)