Bone healing in critical-size defects treated with bone marrow aspirate combined or not with low-level laser therapy: an imunohistochemical study in rat calvaria

Abstract

The purpose of this study is to immunohistochemically analyze the influence of bone marrow aspirate (BMA), low-level laser therapy (LLLT) or their combination on bone healing in surgically created critical-size defects (CSD) in rat calvaria. 80 rats will be divided into 4 groups: Group C (control), Group BMA, Group LLLT and Group BMA/LLLT. 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 Group BMA, the defect will be filled with BMA. In Group LLLT, the defect will receive laser irradiation (GaAIAs laser), will be filled with blood clot and then will be irradiated again. In Group BMA/LLLT, the defect will receive laser irradiation (GaAIAs laser), will be filled with BMA and then will be irradiated again. Mesenchymal stem cells (MSC) of the BMA samples will be quantified by flow cytometry. The animals will be euthanized at 15 or 30 days post-operatively. The area of the original surgical defect and the surrounding tissues will be removed en bloc. The specimes will be processed and embedded in paraffin. Serial sections 5 µm-thick will be cut in a longitudinal direction to the sagittal suture. Some sections will be submitted to immunohistochemical reactions for detection of proliferating cell nuclear antigen (PCNA), runt-related transcription factor - 2 (RUNX-2), BMP-2, osteocalcin (OC), osteopontin (OP) and vascular endothelial growth factor (VEGF). The results will be analyzed by light microscopy. The data will be submitted to statistical analysis. (AU)