A viabilidade dos recursos de otimização do reparo ósseo com o uso da L-PRF e osso bovino em calvárias de ratos. Estudo histométrico e imunoistoquímico

Abstract

Autogenous bone is the only one capable of maintaining the properties of osteogenesis, osteoinduction and osteoconduction. So, one of the strategies used to restore, maintain or improve the function of living tissues is to use substances capable of inducing cellular and tissue proliferation, such as Platelets Rich in Fibrin and Leukocytes (L-PRF), an autologous non-thrombinized graft material that provides effective biological responses due to an increase in the release of cytokines and growth factors during the wound healing process. This study investigated the effect of L-PRF, compared to or associated with Bio-Oss® (bovine bone), an osteoconductive biomaterial, taking into account autogenous bone graft as a standard material for filling bone defects. A defect of 5 mm diameter was performed in the calvaries of 40 rats. These animals were divided into 5 groups of 8 animals each and received blood clot (CO), autogenous bone (AUT), bovine bone (BIO), platelets-rich fibrin and leukocytes (L-PRF) or associated bovine bone and L-PRF (BIO-L-PRF). The animals were euthanized after 4 and 8 weeks. Bone regeneration was assessed by histometric and immunohistochemical analysis. It was observed that the highest mean percentage of bone formation found in the 4 and 8 week was in the BIO-L-PRF group (54.05% ± 2.8349 and 63.58% ± 2.19115). The lowest mean percentage was observed in the CO group for 4 and 8 weeks (16.70% ± 2.4724 and 20.55% ± 0.9842) and with no statistically significant difference between the periods. The comparison between the groups showed statistical similarity between the autogenous group and the Bovine Bone and L-PRF groups. This reinforces the good performance as a filling material promoted by bone bovine and L-PRF, especially when associated in the quantitative and immunohistochemical aspect, since the expressions of OC, RUNX 2 and VEGF evidenced a favorable aspect in the formation of new bone. VEGF was the marker that presented greater expression to be related to the initial cicatricial process, promoting the migration and proliferation of endothelial cells in the region of the defect. Even after weeks, VEGF was found to maintain a moderate expression. It was concluded that the association of L-PRF to bovine bone allowed to improve the bone repair when these biomaterials were inserted in calvarial defects of rats.